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INTRODUCTION

India is a land of immense biodiversity in which two (Eastern Himalayas and The

Western Ghats of India) out of twenty five hot spots of the world are located. This country

is perhaps the largest producer of medicinal herbs and is rightly called the botanical

garden of the world. It is generally estimated that in India over 6000 plants are used in

traditional, folk and herbal medicine, representing about 75% of the medicinal needs of

the Third World countries. Medicinal herbs as potential source of therapeutic aids has

attained a significant role in health system all over the world for both humans and animals

not only in the diseased condition but also as potential material for maintaining proper

health. The market share of herbal products made in developing countries remains

comparatively low due to lack of research and development and the huge investments in

making standardized products.

Though India has a rich biodiversity, the growing demand is putting a heavy strain

on the existing resources. While the demand for medicinal plants is growing, some of

them are increasingly being threatened in their natural habitat. For meeting the future

needs cultivation of medicinal plant has to be encouraged. Today there are at least 120

distinct chemical substances derived from plants that are considered as important drugs

currently in use in one or more countries in the world. Indeed, molecules derived from

natural sources (so-called natural products), including plants, marine organisms and

microrganisms, have played, and continue to play, a dominant role in the discovery of

leads for the development of conventional drugs for various diseases. In terms of a modern

research endeavor, drug development from plants must necessarily imply a multi-

displinary approach. Plants are used medicinally worldwide as sources of many potent

drugs. Traditional medical practitioners use a variety of herbal preparations to treat

different kinds of diseases including microbial infections. (Gunther, 1952; Chopra, 1956;

Gopalan, 1984; Bauddhaloka, 2005).

The World Health Organisation (WHO) estimated that 80% of the population of

developing countries relies on traditional medicines, mostly plant drugs, for their primary

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health care needs. Also, modern pharmacopoeia still contains at least 25% drugs derived

from plants and many others which are synthetic analogues built on prototype compounds

isolated from plants. Demand for medicinal plant is increasing in both developing and

developed countries due to growing recognition of natural products, being non-narcotic,

having no side-effects, easily available at affordable prices and sometimes the only source

of health care available to the poor. Medicinal plant sector has traditionally occupied an

important position in the socio cultural, spiritual and medicinal arena of rural and tribal

lives of India. Medicinal plants as a group comprise approximately 8000 species and

account for around 50% of all the higher flowering plant species of India. Millions of rural

households use medicinal plants in a self-help mode. Over one and a half million

practitioners of the Indian System of Medicine in the oral and codified streams use

medicinal plants in preventive, promotive and curative applications. There are estimated to

be over 7800 manufacturing units in India. In recent years, the growing demand for herbal

product has led to a quantum jump in volume of plant materials traded within and across

the countries. An estimate of the EXIM Bank puts the international market of medicinal

plants related trade at US $ 60 billion per year growing at the rate of 7% only (WHO,

2000).

Medicinal plants are important for pharmacological research and drug

development, not only when plant constituents are used directly as therapeutic agents, but

also as starting materials for the synthesis of drugs or as models for pharmacologically

active compounds. A significant number of modern pharmaceutical drugs are thus based

on or derived from medicinal plants. The need to document plant uses and attempt to

confirm their efficacy remains urgent. The term ethnopharmacology loosely describes the

field covering observation, identification, description and experimental investigation of

the effect of indigenous drugs and its ingredients is truly an interdisciplinary field of

research. Traditional medicine is a powerful source of biologically active compounds.

Ethnopharmacology has become a scientific backbone in the development of active

therapeutics based upon traditional medicine of various ethnic groups.

Ethnopharmacology is the survey of plants of a particular region or cultural tribe

depending on their use in traditional system by choosing a specific therapeutic target.

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Screening program based on ethnopharmacological information has more success rate

than random screening (Papiya Bigoniya and Rana, 2008). Pharmacognosy is closely

related to botany and chemistry, both originated from the earlier scientific studies on

medicinal plants. A field concerned with the description and identification of drugs both in

whole state and powder along with their history, commerce, collection, preparation and

storage (Trease and Evans, 2008).

Medicinal herbs are moving from fringe to mainstream use with a greater number

of people seeking remedies and health approaches free from side effects caused by

synthetic chemicals. Recently, considerable attention has been paid to utilize eco-friendly

and bio-friendly plant-based products for the prevention and cure of different human

diseases. Considering the adverse effects of synthetic drugs, the western population is

looking for natural remedies which are safe and effective (Dubey et al., 2004). It is

documented that 80% of the world’s population has faith in traditional medicine,

particularly plant drugs for their primary healthcare. India is sitting on a gold mine of

well-recorded and traditionally well-practiced knowledge of herbal medicine. This country

is perhaps the largest producer of medicinal herbs and is rightly called the botanical

garden of the world. There are very few medicinal herbs of commercial importance which

are not found in this country. India officially recognizes over 3000 plants for their

medicinal value. It is generally estimated that over 6000 plants in India are in use in

traditional, folk and herbal medicine, representing about 75% of the medicinal needs of

the Third World countries (Rajshekharan, 2002).

Undoubtedly, the plant kingdom still holds many species of plants containing

substances of medicinal value which have yet to be discovered. India is a land of immense

biodiversity in which two out of eighteen hot spots of the world are located. India is also

one of the twelve mega biodiversity countries in the world. The total number of plant

species of all groups recorded from India is 45,000 (the total number may be even close to

60,000, as several parts of India are yet to be botanically explored). Of these, seed-bearing

plants account for nearly 15,000–18,000. India enjoys the benefits of varied climate, from

alpine in the Himalaya to tropical wet in the south and arid in Rajasthan. Such climatic

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conditions have given rise to rich and varied flora in the Indian subcontinent. In order to

promote Indian herbal drugs, there is an urgent need to evaluate the therapeutic potentials

of the drugs as per WHO guidelines. Ironically, not many Indian products are available in

standardized form, which is the minimum requirement for introducing a product in the

western market (WHO, 2000).

The primary benefits of using plant derived medicines are that they are relatively

safer than synthetic alternatives, offering profound therapeutic benefits and more

affordable treatment. The use of medicinal plants in developing countries as a normative

basis for the maintenance of good health has been widely observed. Furthermore, the

increasing reliance on the use of medicinal plants in the industrialized societies has been

traced to the extraction and development of several drugs and chemotherapeutics from

these plants as well as from traditionally used rural remedies. Moreover, in these societies,

herbal remedies have become more popular in the treatment of minor ailments and also on

account of the increasing costs of personal health maintenance (Okigbo et al., 2009).

Some of the useful plant drugs include vinblastine, vincristine, taxol,

podophyllotoxin, camptothecin, digitoxigenin, gitoxigenin, digoxigenin, tubocurarine,

morphine, codeine, aspirin, atropine, pilocarpine, capscicine, allicin, curcumin,

artemesinin and ephedrine among others. In some cases, the crude extract of medicinal

plants may be used as medicaments. On the other hand, the isolation and identification of

the active principles and elucidation of the mechanism of action of a drug is of paramount

importance. Hence, works in both mixture of traditional medicine and single active

compounds are very important. Where the active molecule cannot be synthesized

economically, the product must be obtained from the cultivation of plant material. About

121 (45 tropical and 76 subtropical) major plant drugs have been identified for which no

synthetic one is currently available. The scientific study of traditional medicines,

derivation of drugs through bioprospecting and systematic conservation of the concerned

medicinal plants are thus of great importance (Joy et al., 2001).

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Phytochemical investigations in plants

Successful determination of biologically active compound from plant material is

largely dependent on the type of solvent used in the extraction procedure. Properties of a

good solvent in plant extractions include low toxicity, ease of evaporation at low heat,

promotion of rapid physiologic absorption of the extract, preservative action and inability

to cause the extract to complex or dissociate. As the end product in extraction will contain

traces of residual solvent, the solvent should be non-toxic and should not interfere with the

bioassay. Variation in extraction methods are usually depend on the length of the

extraction period, solvent used, pH of the solvent, temperature, particle size of the plant

tissues and the solvent-to-sample ratio. Another common method is serial exhaustive

extraction which involves successive extraction with solvents of increasing polarity from a

non polar (hexane) to a more polar solvent (methanol) to ensure that a wide polarity range

of compound could be extracted. Other researchers employ soxhlet extraction of dried

plant material using organic solvent (Das, 2010).

The classical method of obtaining constituents of dried plant tissue is to

continuously extract the powdered material in soxhlet apparatus with a range of solvents

to obtain wide range of compounds. Identification of plant constituents can be achieved

from its response to color test, solubility, spectral characteristics and spot formation in

TLC (thin layer chromatography) and PC (paper chromatography). Nowadays, precoated

plates of commercial manufacture are usually employed since these have more uniform

and provide more reproducible results. The most recent being TLC plates coated with

same fine microparticles of silica that are used in HPLC (high performance thin layer

chromatography). Such chromatography is called HPTLC and it usually gives more

efficient and rapid separations than conventional silica layers at shorter time with better

resolution. The basic difference between TLC and HPTLC lies in particle and pore size of

the sorbents. The criteria for phytochemical identification are based on chromatographic

and spectral comparison, the extent of which depends on the class of the compound

(Harbone, 1998; Kokate, 2008).

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Secondary metabolites are a group of compounds that do not get involved in

primary metabolism of the plant. But these compounds are now recognized to be involved

in adaptional and survival mechanism. They are produced in specially designed secondary

metabolic pathways. These compounds help the plants to face adversities, enemies and

competition. Studies on the dynamics of secondary metabolism indicated that here is a

definite turnover of these compounds evidenced by diurnal variation, seasonal variation

and different stages of development. Alkaloids are defensive agents dettering the

herbivore due to their bitter taste; volatile oils act as pheromone for pollination by insects

and protect the plant from microbes, competition, etc; diterpenes or triterpenes perform

wound healing and antimicrobial functions. Phenols act as antioxidant and protect cellular

membranes and tissues containing lipids against oxidation. Anthrocyanins and flavonoids

act as pollinator guide for insects as they are responsible for attractive coloration in

flowers. All sulfur containing compounds are antimicrobial in nature. Cardiac glycosides

are used by plants to protect from herbivore can be used in heart treatment. There are three

major classes of secondary metabolites, the largest group being that of alkaloids followed

by terpenoids and phenolics. Gums and mucilages are polysaccharides but considered as

secondary metabolite due to their function (Daniel, 2006).

Pharmacological action of different alkaloids (Daniel, 2006)

Scientific name Family Pharmacological action

Alkaloid

Papaver somnifreum Papaveraceae Analgesic and narcotics

Morphine and codeine

Campthoteca acuminata Nyssaceae Antitumor agents Campthotecin Strychnos toxifera Loganiaceae Muscle paralyzer Tubocurarine Erythroxylum coca Erythroxylaceae Local anesthetics Cocaine Mandragora officinarum Solanaceae Antispasmodic Atropine and

hyoscine Chinchona officinalis Rubiaceae Cardiac repressant Quinine

Alkaloids have been divided into three major classes depending on the precursors

and the final structure. The true alkaloids are derived from amino acids, are basic and

contain nitrogen in a heterocyclic ring for example, nicotine. Common alkaloid ring

structures include the pyridines, pyrroles, indoles, pyrrolidines, isoquinolines, and

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piperidines (Ncube et al., 2008). Alkaloids are basic plant products possessing nitrogen

containing heterocyclic ring system and exhibiting marked pharmacological activity.

Alkaloids form a heterogenous group and have an alkaline nature due to nitrogen. The

degree of basicity depends on position of nitrogen and other functional groups. They are

usually water insoluble and their salts exist in crystalline form. Almost all alkaloids absorb

UV lignt and have characteristic absorption spectra. Alkaloids are usually toxic at high

concentration and their physiological activity depends on the dosage. They are associated

with different pharmacological actions (Harbone, 1998; Daniel, 2006).

Pharmacological action of different glycosides (Kokate, 2008)

Plant Family Pharmacological action Glycoside Cassia acutifolia Hypericum perforatum

Leguminoceae Hypericaceae

Purgative Antidepressant

Anthracene glycosides

Digitalis purpurea Thevetia nerifolia

Scrophulariaceae Apocynaceae

Cardiotonic Cardiotonic

Cardiac glycosides

Mormodica charantia BAcopa moniera

Cucurbitaceae Scrophulariaceae

Hypoglycemic Nerve tonic

Saponin glycosides

Brassica nigra Cruciferae Counter irritant Isocyanate glycosides

Silybus marianum Gingko biloba

Asteraceae Gingkoaceae

Liver disorders Vascular disorders

Flavonoids glycosides

Ammi visnaga Psoralae corlifolia

Umbelliferae Leguminoceae

Muscle relaxant Luecoderma

Coumarin glycosides

Arctostaphylos uvaursi

Ericaceae

Diuretic

Phenol glycosides

Glycosides are organic compounds which on enzymatic and acid hydrolysis give

sugar (glycone) and non sugar (aglycone) moieties linked by glycosidic bonds. They may

be crystalline or amorphous. Some of their useful actions include cadiatonic, purgative,

analgesic, antirheumatic, demulscent, antiulcer, etc. Based on their aglycone moieties they

include anthracene glycosides, cardiac (steroid) glycosides, saponin glycosides,

isothiocynate glycosides, flavonoid glycosides, coumarin glycosides, phenol glycosides,

etc (Kokate, 2008).

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Terpenoids are based on isoprene molecule (C5 molecule) with different modes of

ring closure, unsaturation and functional groups and are lipid soluble located mostly in

cytoplasm of plant cell. Some are also found to be associated with growth regulating

properties. Terpenoids are classified based on carbon chain into hemiterpenoids (C5),

monoterpenoids (C10), sesquiterpenoids (C15), diterpenoids (C20), sesterterpenoids

(C25), triterpenoids (C30), tertaterpenoids (C40) and polyterpenoids. The terpenoid

essential oil includes monoterpenes and sesquiterpenes, found to be used in perfume and

food industry. Triterpenoids are a heterogeneous collection of biochemical substances

which are derived from squalene (acyclic C30 hydrocarbon) by ring closure and

substitution. They are crystalline compounds and exist as alcohols, aldehydes or

carboxylic acids. Triterpenoids are divided into triterpenes, steroids, saponins and cardiac

glycosides. Saponins are glycoside of triterpenes and sterols. The sugar component

consists of oligosaccharides with 2-5 sugar unit, gluconic acid and aglycone. Sapogenics,

the aglycone may be triterpenes. The foam formation during plant extraction can be

attributed to saponins which have the ability to haemolyse blood cells. Saponins are more

polar then sapogenics due to attachment to glycosidic linkages. Saponins are employed as

expectorant, antitussive and antimicrobial agents (Harbone, 1998; Daniel, 2006).

The term phenolic compound embraces a wide range of plant substances which

possesses a common aromatic ring bearing one or more hydroxyl constituents. These

compounds have a single aromatic ring and include all phenolic alcohols, aldehydes,

ketones and their glycosides. Phenolic substances are water soluble since they are

combined with sugar as glycosides and located in cell vacuoles. Polymeric substances like

lignins, melanins and tannins are polyphenols and occasionally phenolic units are

encountered in proteins, alkaloids and terpenoids. Phenolics are effective antioxidants and

antimicrobial agents. Detection of simple phenols by development of the intense green,

purple, blue or black colors in presence of ferric chloride can be obtained. Majority of

phenolic compounds and flavonoids can be detected with their colors of fluorescence in

UV (since they are aromatic) light. Phenolic compounds are visibly colored and hence can

be easily isolated and purified. This group includes metabolites derived from the

condensation of acetate units (tepernoids), those produced by the modification of aromatic

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amino acids (phenylpropanoids and coumarins), flavonoids, isoflavonoids and tannins.

Flavones, flavonoids and flavonols have been known to be synthesized by plants in

response to microbial infection so it is not surprising that they have been found, in vitro, to

be effective antimicrobial substances against a wide array of microorganisms (Bennet and

Wallsgrove, 1994).

The flavonoids form the largest group but simple monocyclic phenols,

phenylpropanoids and phenolic quinones exist in considerable numbers. Flavonoids are

water soluble phenolic compound derived from the parent substance flavone. They have

conjugated aromatic system and hence show absorption bands in UV and visible region.

Flavonoids are present in combination with glycosides and also in free state. The mixtures

of different flavonoid class of compounds (anthocyanins, proanthocyanidins, flavonols,

flavones, gycoflavones, biflavonyls, chalcones, aurones, neoflavanoids, flavonones and

isoflavonones) which give different colors and fluorescence with chemical and UV

treatment. The different classes are bases on oxidation pattern of C3, additional oxygen

heterocyclic rings and glycosylation. The spectra of properties exhibited by these

compounds include coloring of flowers and fruits, accessory pigments in photosynthesis,

astringency, estrogenic, etc (Harbone, 1998; Daniel, 2006).

Tannins are polyphenols having astringent taste and occur widely in vascular

tissues and associated with woody tissues. They react with proteins to form stable water

soluble polymers hence are capable to transform raw animal skin to leather. Plants rich in

tannins have astringent taste and thus act as major barrier to herbivores. Two main types

of tannins are condensed (flavolans) tannins found in ferns, gynosperms and angiosperms

while hydrolysable tannins found in dicots. Hydrolysable tannins are water soluble simple

phenolic acids esterified with sugar molecules while condensed tannins are water

insoluble polyphenols. Tannins have antifungal, antioxidant properties and are used as

medical astringents. Quinones are aromatic ketones and widely distributed in bark, roots,

etc. They exhibit structural and color variations, thus are largest class of natural coloring

compounds. They are found to be associated with purgative and cathartic action. They are

classified into benzoquinones, naphthaquinones, anthraquinones (mono, bi and tri cyclic

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ring system, respectively) and isoprenoid quinines. Coumarins are formed by lactonization

of o-hydroxy cinnamic acid. They exist in aromatic form and also associated with

glycosides. Furanocoumarins and pyranocoumarins have a furan or pyrano ring attached

to benzene ring of coumarins. Furanocoumarins are associated with spasmolytic and

vasodilating effects. Lignans are dimers formed by condensation or two cinnamic acid or

cinnamyl alcohols through β-carbons of their aliphatic side chains and found to be

extensively used as antioxidants and antimicrobial agents. They are used in treating

malagncies and associated with cathartic action (Harbone, 1998; Daniel, 2006).

Gums and mucilages include all hydrocolloids of plant and are anionic or non

inonic polysaccharides of many monosaccharides. Gums are pathologic compounds

produced in response to injury by gummosis to for a colloid of cell wall and their

ingredients which serve as act as protective layer on wounded tissue. They are amorphous,

translucent and water soluble compounds. Mucilages on the other hand are natural plant

products for the inhibition and retention of water since they form slimy mass with water.

They are esters of sulphuric acid wherin ester groups are polysaccharide complex. But

from a chemical point of view, gums and mucilages are almost identical and serve as

laxatives (Harbone, 1998; Daniel, 2006; Kokate, 2008).

Primary metabolites include carbohydrates, proteins and lipids, since they are

continuously synthesized and utilized. But their storage in tissue without any reason hence

marked as secondary metabolites. Carbohydrates are the major source of energy in plants

made entirely of carbon. They are polyhydroxy aldehydes or ketones and their derivatives.

They are classified as monosaccharide, disaccharides and polysaccharides based on

number of carbon. They are present in tannins, saponins and cardiac glycosides. Dietary

fibres consisit of pectin, cellulose, lignins, etc. They have important effects on gut

functions, ability to absorb water, constipation, diverticular diseases and appendicitis. The

plant world is made of 300 amino acids, wherein 20-26 form proteins while rest are non

protein amino acids. The non proteins occur free or as peptides and exhibit various

biological activity. They are classified into D-amino acids, non α-amino acids,

dicarboxylic acids, amides, sulfur containing amino acids, hydoxy amino acids,

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heterocyclic and alicyclic amino acids. They form important constituents of enzymes and

vitamins (Harbone, 1998; Daniel, 2006).

The identification of biologically active compounds is an essential requirement for

quality control and dose determination of plant-based drugs. A medicinal herb can be

viewed as a synthetic laboratory as it produces and contains a number of chemical

compounds. These compounds are responsible for medical activity of the herb, are usually

secondary metabolites. For example, alkaloids which are nitrogenous principles of organic

compounds combine with acids to form crystalline salts. In addition, herbs may contain

saponins, resins, oleoresins, lactones and volatile oils. Complete phytochemical

investigations of most of the medicinally important herbs of India have not been carried

out so far. This would be beneficial in standardization and dose determination of herbal

drugs. Further, there should be a quality control test for the entire preparation to ensure the

quality of the drug. There is no doubt that most herbs exhibit their effects on a variety of

constituents and the idea of synergy within and between them is also gaining acceptance.

It is not well-documented in most of the herbal medicines whether they are acting truly in

a synergistic way or by additive effects. Clinical evaluation is also difficult, without

knowing the extent to which synergy occurs within the herbal preparations. Some of the

components of the crude drugs may not have any biological activity, Ginger (Zingiber

officinale) is another example of a chemically unstable range of compounds being

responsible for the activity and probably acting synergistically (Dubey et al., 2004). St

John’s wort (Hypericum perforatum, family Hypericaceae) thus represents a good

example of a herb which may exhibit synergism and polyvalent action.

The isolation of physiologically active principles of indigenous plant materials and

the elucidation of their chemical structure and therapeutic status is most frustrating, may

be due to the lack of contribution between botanist, pharmacologist, chemist and

clinicians, because it is only through their cooperation that new therapeutic agents can be

established. Hence drugs of plant origin have failed to acquire full measure of their

importance in the pharmaceutical industry. In this context, American pharmaceutical

industry suggested that 47.2% of the total number of prescription in United States during

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1960 were based on natural products while 52.8% on synthetic drugs. It is quite evident

that studies on medicinal plants continue to offer vast and attractive field of research for

chemist and presently serve as mainstay for providing a big reservoir of physiologically

active constituents for human welfare. Interest in medicinal plants was recorded as a result

of isolation of new alkaloids from Rauwolfia serperntina which gained importance in the

treatment of cardiovascular diseases and mental ailments. Reserpine has been extensively

used in the treatment of hypotension and as an aid in psychotherapy. Discovery of life

saving drugs like vinblastine and vincristine from Vinca rosea, for treatment of of certain

types of cancers including leukemia and Hodkin’s disease have strengthened interest in

active principles of medicinal plants. These investigations have served dual purpose of

isolating new medicinally important substances and providing basis of therapeutic studies

directed towards the synthesis of drugs modeled on the chemical structure of natural

products (Ayatollahi and Malik, 1991).

Plants with antimicrobial activity

Plant derived substances have recently become of great interest owing to their

versatile applications. Medicinal plants have been used for centuries as remedies for

human diseases and offer a new source of biologically active chemical compound as

antimicrobial agent. Medicinal plants are the richest bio-resources of drugs of traditional

medicinal systems, modern medicines, nutraceuticals, food supplements, folk medicines,

pharmaceuticals, intermediate and chemical entitled for synthetic drugs. It has been

estimated that 14 - 28% of higher plant species are used medicinally and that 74% of

pharmacologically active plant derived components were discovered after following up on

ethno medicinal use of the plants. Recently the acceptance of traditional medicine as an

alternative form of health care and the development of microbial resistance to the

available antibiotics has led authors to investigate the antimicrobial activity of medicinal

plants. Substantial use of chemical pesticides induces problems of health and

environmental hazards in agricultural system. So, for human and plants natural products of

antimicrobial activity are best biorational alternatives today. Over the last two decades,

intensive effort has been made to discover chemically useful antibacterial or antifungal

drugs of plant origin. Medicinal plant based antimicrobials represent a vast untapped

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source of pharmaceuticals and further exploration of plant antimicrobials need to occur for

treatment of infectious diseases both in plants and humans while simultaneously for

mitigating many of the side effects that are often associated with synthetic antimicrobials.

Out of the several hundred thousand medicinal plant species around the globe, only a

small portion has been investigated both phytochemically and pharmacologically (Das et

al., 2010).

Existence of humans on the earth is made possible because of the vital role played

by the plant kingdom. Besides providing basic requirements of man, the plants offer

unique protection to mankind by providing innumerable drugs to prevent and treat various

disorders. Drugs used in modern medicine were initially used in crude form in traditional

or folk healing practices. The benefits of plant derived medicines are that they are

relatively safer than synthetic alternatives, offering profound therapeutic benefits and

more affordable treatment. Phytomedicines represent vast untapped sources of drugs

effective in treating infectious diseases simultaneously mitigating many of the side effects

of synthetic antimicrobials (Iwu et al., 1999). In a constant attempt to improve the quality

of life, men have used plants as source of food, shelter, clothing, cosmetic, medicine and

for seeking relief from hardship of life. Some plants are known as medicinal because they

contain active substances that cause certain reaction from relenting to the cure of diseases

of man (Sliva-Junor, 1994).

Knowledge of medicinal plants sometimes means the only therapeutic resource (Di

Stasi, 1996) of some communities and ethnic group (Odunbaku et al., 2008). Infectious

diseases are a major cause of morbidity and mortality worldwide (WHO, 2004). Clinical

microbiologists have two reasons to be interested in the topic of antimicrobial plant

extracts. First, it is very likely that these phytochemicals will find their way into the

arsenal of antimicrobial drugs prescribed by physicians; several are already being tested in

humans. It is reported that, on average, two or three antibiotics derived from

microorganisms are launched each year. After a downturn in that pace in recent decades,

the pace is again quickening as scientists realize that the effective life span of any

antibiotic is limited. Worldwide spending on finding new anti-infective agents (including

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vaccines) is expected to increase 60% from the spending levels in 1993. New sources,

especially plant sources, are also being investigated. Second, the public is becoming

increasingly aware of problems with the over prescription and misuse of traditional

antibiotics. In addition, many people are interested in having more autonomy over their

medical care. A multitude of plant compounds (often of unreliable purity) is readily

available over-the-counter from herbal suppliers and natural-food stores, and self-

medication with these substances is common place. The use of plant extracts, as well as

other alternative forms of medical treatments, is enjoying great popularity in the late

1990s. Earlier in this decade, approximately one-third of people surveyed in the United

States used at least one “unconventional” therapy during the previous year. It was reported

that in 1996, sales of botanical medicines increased 37% over 1995 (Cowan, 1999).

Medicinal plants have been used for centuries as remedies for human diseases and

offer a new source of biologically active chemical compound as antimicrobial agent.

Medicinal plants are the richest bio-resources of drugs of traditional medicinal systems,

modern medicines, nutraceuticals, food supplements, folk medicines, pharmaceuticals,

intermediate and chemical entitled for synthetic drugs (Hammer et al., 1999). The

evaluation for antimicrobial agent of plant origin begins with thorough biological

evaluation of plant extracts to ensure efficacy and safety followed by identification of

active principles, dosage formulations, efficacy and pharmacokinetic profile of the new

drug. Many plants have been used because of their antimicrobial traits and antimicrobial

properties of plants have been investigated by a number of researchers worldwide. Ethno

pharmacologists, botanists, microbiologists and natural product chemists are searching the

world for phytochemicals which could be developed for treatment of infectious diseases

(Tanaka et al., 2006).

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List of plants with antimicrobial activity (Cowan, 1999)

Common name Scientific name Compound Class Activity

Aloe Aloe barbadensis, Aloe vera Latex Complex mixture Corynebacterium,

Salmonella, Streptococcus

Apple Malus sylvestris Phloretin Flavonoid derivative General

Basil Ocimum basilicum Essential oils Terpenoids Salmonella, bacteria

Bay Laurus nobilis Essential oils Terpenoids Bacteria, fungi

Betel pepper Piper betel Catechols, eugenol Essential oils General

Black pepper Piper nigrum Piperine Alkaloid Fungi, Lactobacillus, Micrococcus, E. coli, E. faecalis

Blueberry Vaccinium spp. Fructose Monosaccharide E. coli

Buchu Barosma setulina Essential oil Terpenoid General

Buttercup Ranunculus bulbosus Protoanemonin Lactone General

Ceylon cinnamon

Cinnamomum verum

Essential oils, others Terpenoids, tannins General

Chili peppers, paprika

Capsicum annuum Capsaicin Terpenoid Bacteria

Clove Syzygium aromaticum Eugenol Terpenoid General

Fava bean Vicia faba Fabatin Thionin Bacteria

Garlic Allium sativum Allicin, ajoene Sulfoxide General

Henna Lawsonia inermis Gallic acid Phenolic Staphylococcus aureus

Olive oil Olea europaea Hexanal Aldehyde General

Onion Allium cepa Allicin Sulfoxide Bacteria, Candida

Papaya Carica papaya Latex Mix of terpenoids, organic acids, alkaloids General

Peppermint Mentha piperita Menthol Terpenoid General

Periwinkle Vinca minor Reserpine Alkaloid General

Quinine Cinchona sp. Quinine Alkaloid Plasmodium spp.

Turmeric Curcuma longa Curcumin Terpenoids Bacteria, protozoa

Plants have limitless ability to synthesize aromatic secondary metabolites, most of

which are phenols or their oxygen-substituted derivatives. Important subclasses in this

group of compounds include phenols, phenolic acids, quinones, flavones, flavonoids,

flavonols, tannins and coumarins. These groups of compounds show antimicrobial effect

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and serves as plant defense mechanisms against pathogenic microorganisms (Das et al.,

2010). Antimicrobial activity of Cassia alata was noticed against E. coli and fungi

(Ikenebomeh et al., 1988). Water extract of Senna alata showed antimicrobial activity

against B. subtilis only but other reports of antimicrobial activity exists (Adebayo et al.,

1991, Ibrahim and Osman 1995).

Standard criteria for in vitro evaluation of antimicrobial activity of plants differ

among authors. Results obtained from antimicrobial efficacy of plant extract is often

difficult to compare with published results due to the influence of several factors, that is,

environment and climatic conditions during plant growth, choice of plant extracts, choice

of extraction methods and antimicrobial tests employed and on test microorganisms

(Nostro et al., 2000 and Hammer et al., 1999). The beneficial medicinal effect of plant

materials basically results from the secondary products present in the plant and is not

usually attributed to a single compound but a combination of the metabolites (Parekh et

al., 2005). Because of available antimicrobials failure to treat infectious diseases, many

researchers have focused on the investigation of natural products as source of new

bioactive molecules. A variety of methods are found for this purpose and since not all of

them are based on same principles, results obtained will also be profoundly influenced not

only by the method selected, but also by the microorganisms used to carry out the test, and

by the degree of solubility of each test compound. The test systems should ideally be

simple, rapid, reproducible, inexpensive and maximize high sample throughput in order to

cope with a varied number of extracts and fractions. The complexity of the bioassay must

be defined by laboratory facilities and quality available personnel. The currently available

screening methods for the detection of antimicrobial activity of natural products fall into

three groups, including bioautographic, diffusion, and dilution methods. The

bioautographic and diffusion methods are known as qualitative techniques since these

methods will only give an idea of the presence or absence of substances with antimicrobial

activity. On the other hand, dilution methods are considered quantitative assays once they

determine the minimal inhibitory concentration. Antimicrobial activities reported in the

literature have been evaluated with diverse sets of methodologies, degrees of sensitivity,

17

amount of test compounds and microbial strains, often difficult to compare (Cowan,

1999).

Plants with antihelmintic activity

The World Health Organization estimates that a staggering two billion people

harbor parasitic worm infections. Parasitic worms also infect livestock and crops, affecting

food production with a resultant economic impact. Despite this prevalence of parasitic

infections, the research on anthelmintic drug is poor. As per WHO, only few drugs are

frequently used in the treatment of helminthes in human beings. Anthelmintics from the

natural sources may play a key role in the treatment of these parasite infections (Aswar

Manoj et al., 2008). Helminth infections are among the most common infections in

humans, affecting a large population of the world. Although the majority of infections due

to worms are generally limited to tropical regions and pose a great threat to health and

contribute to the prevalence of malnutrition, anaemia, eosinophilia and pneumonia

(Bundy, 1994). Parasitic diseases cause severe morbidity affecting mainly population in

endemic areas with major economic and social consequences (Tagbota and Townson,

2001). The gastro-intestinal helminthes becomes resistant to currently available

antihelmintic drugs therefore there is a foremost problem in treatment of helminthes

diseases (Sondhi et al., 1994), hence there is an increasing demand towards natural

antihelmintics.

Parasitic worms also infect livestock and crops, affecting food production with a

resultant economic impact. Also of importance is the infection of domestic pets. Indeed,

the animal market is a major economic consideration for animal health, thus companies

are undertaking drug discovery programmes. Despite the prevalence of parasitic worms,

anthelmintic drug discovery is poor in relation of the pharmaceutical industry. The simple

reason is that the nations which suffer most from these tropical diseases have little money

to invest in drug discovery or therapy. It comes as no surprise therefore that the drugs

available for human treatment were first developed as veterinary medicines. There is thus

a pitifully small repertoire of chemotherapeutic agents available for treatment. In some

respects, this situation has been exacerbated by the remarkable success of ivermectin over

18

the last twenty years (Geary, 2005), which has decreased motivation for anthelmintic drug

discovery programmes (Geary Patel et al., 1999). This prompts concern, as anthelmintic

resistance has been widely reported in livestock and it may also only be a matter of time

before this phenomenon occurs in parasites of humans.

Helminth infections are among the most common infections in man, affecting a

large proportion of population all over the world. In developing countries they pose a large

threat to public health and contribute to the prevalence of malnutrition, anaemia,

eosinophilia and pneumonia. Although the majority of infections caused due to worms are

generally limited to tropical regions. Parasitoses have been of concern to the medical field

for centuries and the helminthes still cause considerable problems for human beings and

animals. During the past few decades, despite numerous advances made in understanding

the mode of transmission and the treatment of these parasites, there are still no efficient

products to control certain helminths and the indiscriminate use of some drugs has

generated several cases of resistance. Furthermore, it has been recognized recently that

anthelmintic substances having considerable toxicity to human beings are present in foods

derived from livestock, posing a serious threat to human health (Patel et al., 2011). Some

workers have reported antihelmintic activity in the essential oils of Piper betle Linn.,

Anancardium occidentale Linn. and seed oils of Gynandropsis gynandra Linn., Impatiens

balsamina Linn., Celastrus peniculata Willd., Embelia ribes Burm. F. and Mucuna prurita

Hook. against the earthworm Pheretima Posthuma (Mali and Mehta, 2008).

Plants with potential anthelmintic activity (Behnke et al., 2008)

Species Enzymes known to be contained Papaya papain, chymopapain, caricain, glycyl endopeptidase Fig ficin, ficain Pineapple ananain, fruit bromelain, stem bromelain, comosain Kiwi fruit Actinidain Egyptian milkweed Asclepain Cowhage Mucunain

19

Plants providing protection against hepatic and renal disorders.

Several chemicals have been known to induce hepatotoxicity. Carbontetrachloride

(CCl4), Galactosamine, d-Galactosamine/Lipopolysachharide (GalN/LPS), Thioacetamide,

antitubercular drug paracetamol, arsenic etc are used to induce experimental

hepatotoxicity in laboratory animals. Liver injury due to CCl4 in rats was first reported in

1936 (Cameron et al., 1936) and has been widely and successfully used by many

investigators (Handa et al., 1990; Shirwaiker et al., 1996). Carbon tetrachloride is

metabolized by cytochrome P-450 in endoplasmic reticulum and mitochondria with the

formation of CCl3O*, a reactive oxidative free radical, which initiates lipid peroxidation

(Zimmerman et al., 1976; Agarwal et al., 1983).

CCl4 CCl3O- + O-

Administration of a single dose of CCl4 to a rat produces, within 24 hrs, a

centrilobular necrosis and fatty changes (Cameron et al., 1936). The poison reaches its

maximum concentration in the liver within 3 hrs of administration. Thereafter, the level

falls and by 24 hrs there is no CCl4 left in the liver (Dawkins, 1963). The development of

necrosis is associated with leakage of hepatic enzymes into serum. Dose of CCl4 that

induces hepatotoxicity ranges from 0.1 to 3 ml/kg administered intraperitoneally.

Nature has provided an excellent storehouse of remedies to cure all the ailments of

mankind. In ancient days, almost all the medicines used were from natural sources,

particularly from plants. Plants continue to be an important source of new drugs even

today. The importance of botanical, chemical and pharmacological evaluation of plant-

derived agents used in the treatment of human ailments has been increasingly recognized

in the last decades. Herbal remedies are widely used for the treatment and prevention of

various diseases and often contain highly active multitude of chemical compounds.

Modern research is now focusing greater attention on the generation of scientific

validation of herbal drugs based on their folklore claim. In this modern era, a large number

of Indian population still relies on the traditional system of medicine, which is mostly

20

plant based. Free radical initiating auto oxidation of cellular membrane lipids can lead to

cellular necrosis and is now accepted to be important in connection with a variety of

pathological conditions. Liver is an aerobic organ which generates reactive oxygen species

that induce oxidative tissue damage. These radicals react with cell membranes and induces

lipid per oxidation or causes inflammation, which may result as important pathological

mediators in many clinical disorders such as heart disease, diabetes, gout and cancer.

Reduction of these radicals by antioxidant molecules is crucial for the protection of cells

against various disorders. Development of life threatening diseases like cancer and also

liver disorders are linked to the availability of these antioxidants (Vadivu et al., 2008).

Classification of hepatotoxins

Category of agent Mechanism Histological lesion Examples 1.Intrisic toxicity a) Direct

Membrane injury destruction of structural basis of cell metabolism

Necrosis (zonal)and /or steatosis

CCl4

CHCl3

Phosphorus

b)Indirect Cytotoxic Interference with specific metabolic pathway leads to structural injury

Steatosis or Necrosis

Ethionine Thioacetamide Paracetamol Ethanol

c) Cholestatic Iinterference with hepatic excretory pathway leads to cholestasis

Bile duct injury

Rifampicin Steroids

2.Host idiosyncrasy a) Hypersensitivity

Drug allergy Necrosis or cholestasis

Sulfonamides Halothane

b)Metabolic Abnormality

Production of hepatotoxic metabolites

Necrosis or cholestasis

Isoniazide

Liver is the largest organ in the vertebrate body and also an important organ

actively involved in metabolic functions such as production and secretion of bile,

prothrombin and fibrinogen. The liver is also responsible for detoxifying poisonous

substances in the body by transforming and removing toxins, waste, and pollutant

21

xenobiotics. A large number of medicinal preparations are recommended for the treatment

of liver disorders and quite often claimed to offer significant relief which would not be

possible in absence of reliable liver-protective drugs in modern medicine, (Jain et al.,

2009). Carbon tetrachloride also known as tetra chloromethane is known to have

hepatotoxic effects. On exposure, the liver is inflamed and the hepatocytes destroyed

(Sanni et al., 2007). Though CCL4 is a potent hepatotoxin, in addition to hepatic problems

CCL4 also causes disorders in kidney. Exposure to CCL4 causes acute and chronic renal

injuries (Manna et al., 2006). Herbal drugs are prescribed widely even when their

biologically active components are unknown because of their effectiveness, fewer side

effects and relatively low cost (Krishna Mohan et al., 2007). Certain toxic chemicals and

medicines can cause damage to organs, which has been recognized as a toxicological

problem. However, herbal medicines are known to play an important role in the treatment

of various ailments. Many traditional practitioners have claimed that numerous medicinal

plants and their formulations can be effectively used for the alleviation of different types

of liver and kidney diseases (Vadivu et al., 2008). Casuarina equisetifolia, Cajanus cajan,

Glycosmis pentaphylla, Bixa orellana, Argemone mexicana, Physalis minima, Caesalpinia

bonduc were observed to provide dose-dependent protection against CCl4 induced

hepatocellular injury (Ahsan et al., 2009).

Alterations in kidney structure and function are frequently found in severe liver

disease and once liver function falls below a critical threshold, sodium retention occurs

followed by ascites, associated with profound disturbances of splachnic and systemic

hemodynamics which in turn may affect renal function (Schrier, 1988; Weinberg, 1991).

As disease progresses, constriction of intrarenal vascular system favors marked sodium

and water retention, leading to refractory ascites, a progressive rise in plasma creatinine

levels and reduction of renal clearances (decompensated cirrhosis). Persistent renal

hypoxia may also induce tubular damage (Gentilini et al., 1999). Development of renal

failure in patients with liver failure is frequent, it occurs in approximately in 55% of the

patients. This complication may result when the cirrhotic individual is exposed to

xenobiotics, either therapeutic drugs or environmental pollutants, especially heavy metals.

Renal function is rarely restored in the absence of hepatic recovery (Moore, 1999).

22

Administration of carbon tetrachloride (CCl4) to rats results in a reproducible experimental

model of cirrhosis that resembles the disease in humans and provides a tool to study liver-

kidney interrelationships (Mclean et al., 1969; Perez, 1983). Previously experimental

model of acute liver and renal damage was produced by intragastric administration of a

single dose of CCl4 to cirrhotic rats. In this experimental model there were hemodynamic

and renal functional alterations similar to those observed in the human with

decompensated cirrhosis. This model is useful to study the pathogenesis of renal failure

associated with liver damage when the hepatic function decrease after an acute liver

damage (Rincon et al., 1999).

In spite of tremendous advances in modern medicine no effective drugs are

available, which stimulates liver functions and offer protection to the liver from the

damage or help to regenerate hepatic cells. In absence of reliable liver-protective drugs in

modern medicine, a large number of medicinal preparations are recommended for the

treatment of liver disorders and quite often claimed to offer significant relief. Attempts are

being made globally to get scientific evidences for these traditionally reported herbal

drugs (Jain et al., 2009). In view of severe undesirable side effects of synthetic agents,

there is growing focus to follow systematic research methodology and to evaluate

scientific basis for the traditional herbal medicines that are claimed to possess

hepatoprotective activity. A single drug cannot be effective for all types of severe liver

diseases. Therefore, indigenous medicinal plants are being investigated (Samundram et

al., 2009).

In the status of normal metabolism, the levels of oxidants and antioxidants in

humans are maintained in balance, which is important for sustaining optimal physiological

conditions. Overproduction of oxidants in certain conditions can cause an imbalance,

leading to oxidative damage to large biomolecules such as lipids, DNA, and proteins (Jie

Sun et al). Oxidative stress results from either a decrease of natural cell antioxidant

capacity or an increased amount of reactive oxygen species (ROS) in organisms. When the

balance between oxidants and antioxidants in the body is shifted by the overproduction of

free radicals, it will lead to oxidative stress and DNA damage. When left unrepaired, it can

23

cause base mutation, single- and double-strand breaks, DNA cross-linking, and

chromosomal breakage and rearrangement (Yi-Fang Chu et al., 2002). The importance of

natural antioxidants has been clarified by studies which have demonstrated that the

consumption of foods rich in such phytochemicals can exert beneficial effects upon

human health, possibly by interfering in the processes involved in reactive oxygen and

nitrogen species mediated pathologies. This has resulted in resurgence in phyto-

pharmacognosy with extensive attention upon the role that plant secondary metabolites

may have in preventative medicine (Damein-Dorman et al., 2003).

Plants having hepatoprotective activity (Khabiya and Joshi, 2010)

Plant Scientific name Plant Part Holy Milk Thistle Silybum marianum Seed, fruits Amla Phyllanthus niruri Whole plant Indian bearberry Berberis aristata Root stem bark Turmeric Curcuma longa Rhizome Liquorice Glycyrrhiza glabra Root Tulsi Ocimum sanctum Whole plant, roots, seed.

Plants with antidiabetic activity

Diabetes mellitus has been known since ages and the sweetness of diabetic urine

has been mentioned in Ayurveda by Sushruta. Its pharmacotherapy however is over 80

years old. The word diabetes was coined by a Greek physician in the first century A.D. In

the 17th century, Willis observed that the urine of diabetics as wonderfully sweet as if

imbued with honey or sugar. The presence of sugar in the urine of diabetics was

demonstrated by Dobson in 1755. Diabetes is a chronic disease affecting around 2-3 % of

the population worldwide. Unfortunately, after the introduction of sulfonylurea and

metformin about 50 years back no major lead has been obtained in this direction of finding

a proper drug for diabetes. Plant materials which are being used as traditional medicine for

the treatment of diabetes are considered one of the good sources for a new drug or a lead

to make a new drug. Plant extract or different folk plant preparations are being prescribed

by the traditional practioners and also accepted by the users for diabetes like for any other

diseases in many countries especially in third world countries. Now a days more than 400

plants are being used in different forms for hypoglycaemic effects all the claims

24

practitioners or users are neither baseless nor absolute. Therefore, a proper scientific

evaluation for screening of plant by pharmacological tests followed by chemical

investigations is necessary. Diabetes mellitus is wide spread disorder, which has long been

in the history of medicine. Before the advent of insulin and oral hypoglycaemic drugs the

major form of treatment involved the use of the plants. But now from the last two decades

there has been a new trend in the preparation and marketing of herbal drugs. Further it has

been estimated that in the U.S. 25% of all prescription dispensed from community

pharmacies contain plant extracts (Wadkar et al., 2008).

On the basis of etiology two main categories of diabetes are recognized, viz.

primary diabetes and secondary diabetes. Primary diabetes is divided into two types i.e.

Juvenile onset diabetes which is also referred as Type 1 or Insulin dependent diabetes

mellitus (IDDM) and Maturity onset diabetes which is also referred as Type II / Non-

insulin dependent diabetes mellitus (NIDDM). In Juvenile onset diabetes there is a

profound decrease in the number of b cells in the islet of Langerhans and thus there is

absolute deficiency of insulin. The main treatment for this type is insulin. The NIDDM

patients are usually obese and the treatment is usually dietary, though supplementary oral

hypoglycaemic drugs. It is diagnosed by blood or urinary glucose measurement. Insulin

resistances as well as loss of insulin secretion contribute to the onset of disease. The

symptoms of secondary diabetes are pancreatic dysfunction (pancreatitis,

pancreatectomy), hormonal imbalance (eg : acromegaly, pheochromacytoma), Cushing’s

syndrome, glucagonoma, and drugs or chemical induced reactions (eg: glucocorticoids,

anticancer agents, streptozotocin or diazoxide, thiazide, some psychoactive agents).

Diagnosis of early Diabetes Mellitus in diabetes are hyperglycemia, glycosuria, loss of

weight due to increased breakdown of fat and tissue protein, increased production of

ketone bodies by liver and their incomplete utilization by the tissue leading to their

accumulation in blood (Ketosis) and elimination in urine (Ketonuria), lowering of PH of

blood due to circulating keto acids (acidosis), dehydration due to elimination of large

amounts of water with glucose in urine, increased levels of lipid, fatty acids and

cholesterol in blood (lipemia) and increased tendency to develop cataract in the eye and

atheromatous and artherosclerotic lesions of blood vessels (Wadkar et al., 2008).

25

Diabetes mellitus is a metabolic disorder of the endocrine system. The disease is found

in all parts of the world and is rapidly increasing worldwide. People suffering from

diabetes cannot produce or properly use insulin, so they have high blood glucose. Type 2

diabetes, non–insulin-dependent diabetes mellitus, in which the body does not produce

enough insulin or properly use it, is the most common form of the disease, accounting for

90%–95% of cases. Type 2 is nearing epidemic proportions as a result of an increased

number of elderly people and a greater prevalence of obesity and sedentary lifestyle. The

cause of diabetes is a mystery, although both genetic and environmental factors such as

obesity and lack of exercise appear to play a role. According to World Health

Organization projections, the diabetic population is likely to increase to 300 million or

more by the year 2025. Currently available therapies for diabetes include insulin and

various oral antidiabetic agents such as sulfonylureas, biguanides, a-glucosidase

inhibitors, and glinides, which are used as monotherapy or in combination to achieve

better glycemic regulation. Many of these oral antidiabetic agents have a number of

serious adverse effects; thus, managing diabetes without any side effects is still a

challenge. Therefore, the search for more effective and safer hypoglycemic agents has

continued to be an important area of investigation. The hypoglycemic effect of several

plants used as antidiabetic remedies has been confirmed, and the mechanisms of

hypoglycemic activity of these plants are being studied. New natural products reported

from 2001 to 2004 with antidiabetic potential that have potent medicinal activities with

diverse structures (Jung et al., 2006).

Diabetes mellitus is a disease in which blood vessels of glucose (sugar) are high

because the body does not produce or properly use insulin. There are two major forms of

diabetes mellitus. Type 1 diabetes develops when the pancreas does not produce insulin.

Type 2 diabetes occurs when the body cell resist insulin’s effect (Microsoft Encarta,

2009). This condition leads to elevated levels of blood glucose. The normal range of blood

glucose level for blood glucose level is between 70-110mg/dl. Insulin is a hormone that

helps to maintain normal blood glucose level by making the body’s cell absorbs glucose

(sugar) so that it can be as a source of energy. In people with diabetes glucose levels build

26

up in the blood and urine causing excessive urination, thirst, hunger and problems with

fats and protein metabolism because the body cannot convert glucose into energy, it

begins to break down stored fats for fuel. This produces increasing amounts of acidic

compounds in the blood called ketone bodies which interfere with cellular respiration

energy producing process in cells. Alloxan induces diabetes mellitus in rats. Alloxan, a

beta cytotoxin, induces diabetes in a wide variety of animal species through damage of

insulin secreting cell. These animals develop characteristic similar to type 1 diabetes in

humans. Hypercholesterolemia and hypertriglyceridemia are common complications of

diabetes mellitus (Rerup, 1999).

Coopertein and Watkins (1978), Lazarow (1964) have shown that alloxan probably

exerts toxic effect on the beta-cells by selectively interacting with certain components of

the plasma membrane. This results in an altered permeability which permits the diffusion

of extra cellular fluid markers such as D-mannitol and insulin into the surrounding

incubation medium. However, the fact that only beta-cell components of intermediate cells

are affected by alloxan suggests that there is no comparable damage to their plasma

membrane as occurs in the beta-cell (Cooperstein, 1964), but is consistent with the

possibility that alloxan interacts with the membranes of the beta-cell cytoplasmic

organelle. In intermediate cells this imitates the remarkably selective recognition and an

autophary of these organelles. The same considerations probably apply to the effects of

streptozotoxia on the intermediate cells. Alloxan is known to induce diabetic renal

changes as well as causing nephrotoxic alterations however. No ultra structural study has

been performed to differentiate diabetic verses toxic effect of tubules and glomerulus

(Andrew et al, 1992).

Diabetes mellitus is a debilitating and often life-threatening disorder with

increasing incidence throughout the world. Diabetic complications arise partly from

glycosylation damage to structural and functional proteins and reflect chronic failure to

maintain blood glucose homeostasis. Other complications such as diabetic nephropathy,

diabetic retinopathy, diabetic neuropathy and diabetic cardiomyopathy prevail as a result

of hyperglycemia. A scientific investigation of traditional herbal remedies for diabetes

27

may provide valuable leads for the development of alternative drugs and strategies.

Alternatives are clearly needed for better management of diabetes because of high cost

and poor availability of current therapies for many rural populations, particularly in

developing countries. Diabetic nephropathy is one of the microvascular complications of

diabetes. The pathophysiology involves an interaction between metabolic and

hemodynamic factors. Metabolic factors include advanced glycation, increased formation

of polyols and activation of protein kinase-C. Hemodynamic factors include systemic

hypertension, intraglomerular hypertension and the role of vasoactive hormones, such as

anglotensin II. Clinical course progresses from microalbuminuria to overt proteinuria and

then to renal failure. The field of herbal medicines research has been gaining significant

importance in the last few decades and the demand to use natural products in the treatment

of diabetes is increasing worldwide. The available literature shows that there are more

than 400 plant species showing antidiabetic activity. Although some of these plants have

great reputation in Ayurveda, the indigenous Indian system of medicine, many remain to

be scientifically established (Rao and Nammi, 2006). Diabetes mellitus is one of the

common metabolic disorders and 1.3% of the population suffers from this disease

throughout the world. Insulin and oral hypoglycemic agents like sulphonylureas and

biguanides are still the major players in the management of the disease. Due to lack of

insulin, hyperglycemia and glycosuria almost invariably occur. The search for a curative

agent against this disease resulted in the introduction of several hypoglycemic agents.

Some of which are used therapeutically. However, various harmful side effects and weak

effectiveness of them made their use limited and the search to find more effective agents

continues. Investigation in the plant kingdom culminated in the discovery of many herbal

hypoglycemic agents (Tatiya et al., 2011).

Traditional medicines from readily available medicinal plants offer great potential for

the discovery of new antidiabetic drugs. Many traditional plant treatments for diabetes

exist, a hidden wealth of potentially useful natural products for diabetes control.

Nonetheless, few traditional antidiabetic plants have received scientific or medical

scrutiny, despite recommendations by the World Health Organization in 1980 that this

should be undertaken. Medicinal plants that are the most effective and the most commonly

28

studied in relation to diabetes and its complications are: Gentiana olivieri griseb

(Gentianaceae), Bauhinia forficata koeingii (Leguminosae), Eugenia jambolana L.

(Myrtaceae), Lactuca indica L. (Compositae), Mucuna pruriens Bak. (Leguminosae),

Tinospora cordifolia W. (Menispermaceae), Momordica charantia L. (Cucurbitaceae),

Aporosa lindleyana Baill (Euphorbiaceae), Cogent db, Myrtus communis L. (Myrtaceae),

Rhizoma Polygonati Odorati (Liliaceae), and Terminalia pallida Brand. (Combretaceae).

Most of these plants have shown varying degrees of hypoglycemic and anti-

hyperglycemic activity. Among active medicinal herbs, Momordica charantia L.

(Cucurbitaceae), Pterocarpus marsupium Roxb. (Leguminoceae), and Trigonella foenum

greacum L. (Leguminosae) have been reported to be beneficial for treatment of type 2

diabetes (Jung et al., 2006).

Some plants having hypoglycemic activity (Grover, 2002; Srinivasa, 2005)

Plant Plant Part Type of Test Sample Trigonella foenum-gracecum seed Alcohol ,water extract Nephoelepsis tuberose bulb juice Costus specious rhizome juice Plantago ovata husk Powder Allium sativum bulb juice Hemidesmus indicus root alcoholic extract Allium cepa bulb juice

Plants with anticancer activity

Cancer, a major public health problem worldwide, is a group of diseases

characterized by uncontrolled growth and spread of abnormal cells. It affects all people,

the young and old, the rich and poor, men, women and children. Cancer is one of the

leading causes of death in the world and its incidence is still increasing, particularly in

developing countries. It is the second leading cause of death in developed countries, and is

among the three leading causes of death for adults in developing countries (Parkin et al.,

2001). External factors such as tobacco, chemicals, radiation, infectious organisms and

internal factors such as inherited mutations, hormones and immune status can be able to

cause cancer. These risk factors may act together or in sequence to initiate or promote

carcinogenesis (American Cancer Society, 2005). Many different types of chemical

29

exposures can increase the incidence of tumors in humans (Wogan et al., 2004). The only

types of radiation proven to cause human cancer are high-frequency ionizing radiation and

ultraviolet radiation. Exposure to sunlight causes almost all cases of basal and squamous

cell skin cancer and is a major cause of skin melanoma (Moan et al., 2008). Cancers

triggered by infections are more prevalent in the developing world. Both DNA and RNA

viruses were documented as a causative factor of experimental carcinogenesis (Shillitoe,

1991). More than 100 oncogenes have been identified to date, and many among them have

been implicated in carcinogenesis, including ras, c-myc, erb-B2 and epidermal growth

factor receptor (Duesberg and Liu, 2003; Carbone and Pass, 2004). Cancer can be treated

by surgery, radiation therapy, chemotherapy and immunotherapy. Cancers that are most

often cured are breast, cervix, prostate, oral, colon and skin, if they are diagnosed early.

Improving the quality of life of patients living with cancer and dying from cancer is

therefore an urgent humanitarian need. Indian sub-continent is rich in its diversity of flora,

being a tropical country with a large spread of rain forests and river basins. It is

floristically rich with about 33 percent of its botanical wealth (over 15,000 species of

higher plants) being endemic. Numerous bioactive compounds have been isolated from

plant sources and several of them are currently in clinical trials. Plant-derived compounds

have been a vital source of varied clinically useful anti-cancer agents: Camptothecin

derivatives (Kepler et al., 1969), Topotecan and Irinotecan, Etoposide, derived from

Epipodophyllotoxin (Utsugi et al., 1996), and Paclitaxel (taxol) (Cragg and Newman,

2005). Furthermore, other potent molecules include Vinca rosea alkaloids (Vinblastine,

Vincristine) (Johnson et al., 2001), Flavopiridol, a semi-synthetic analogue of the

chromone alkaloid and Rohitkine, a pyridoindole alkaloid derived from leaves of

Ochrosia species (Arguello et al., 1998). The research on anticancer drug development is

largely dependent on exploring potential phytochemicals.

Polycyclic aromatic hydrocarbons (PAHs) are products formed by incomplete

combustion of organic matter. Sources of PAHs include industrial and domestic oil

furnaces, gasoline, and diesel engines. PAHs are widely distributed in our environment

and are implicated in various types of cancer. Enzymatic activation of PAH’s leads to the

generation of active oxygen species such as peroxides and superoxide anion radicals,

30

which induce oxidative stress in the form of lipid peroxidation. The PAH 7,12-dimethyl-

benz(a)anthracene (DMBA) acts as a potent carcinogen by generating various reactive

metabolic intermediates leading to oxidative stress. It is therefore imperative to search

alternative drugs for the treatment of liver disease to replace the currently used drugs of

doubtful efficacy and safety (Bishayee et al., 2000). Most tumor initiating agents either

generate or are metabolically converted to electrophilic reactants which bind covalently to

cellular DNA (Slaga et al., 1987; DiGiovannio, 1992). For a number of PAH's, including

DMBA the ultimate carcinogen is so called Bay-region dihydrodiol epoxide, produced

during cellular metabolism (Harry, 2001). Free radicals and these modified DNA bases

have been strongly implicated in carcinogenesis in general (Floyd, 1990; Mollins, 1993).

A high correlation has been found to occur between the dose of administered DMBA and

the levels of total DNA adducts in liver and target organ epithelial cells. Presumably this

is due to the fact that liver cells have a greater capacity of metabolizing PAHs, as

compared with the target cells for tumorigenicity, which become more readily saturated

(Izzotti et al., 1999). DMBA is the most well known polycyclic aromatic hydrocarbon that

is used as a chemical inductor of model mammary carcinogenesis (Huggins et al., 1961).

The main advantage of using DMBA as chemical carcinogen in rodent model is that it

closely mimics human breast disease. Both of these cancers arise from ductal epithelial

cells. Histopathological characterization of DMBA-induced mammary hyperplastic,

premalignant and malignant lesions shows that rat mammary adenocarcinomas and the

most common human breast carcinomas share several histological and morphological

similarities (Costa et al., 2002).

Chemical carcinogen like DMBA binds with DNA which is considered to be

essential for its tumor inducing ability. Inhibitory effect of any chemopreventive agent

against DMBA induced tumorigenesis correlates with decreased binding of DMBA to

DNA. Cell proliferation has important role in carcinogenesis as cancer proceeds through

inactivation of negative regulators of cell proliferation and activation of positive regulators

of cell proliferation (Coleman and Tsongalis, 2006). Toxic manifestation of DMBA is

associated with its oxidative metabolism leading to the formation of reactive metabolites

(epoxides and quinines) capable of generating free radicals. Metabolism of PAHs like

31

7,12-dimethyl benz(a)anthracene by the mixed function oxidases system (MFO) often

results in the formation of oxy-radicals “O2−, 1O2, H2O2, OH,” which bind covalently to

nucleophillic sites on cellular macromolecules thereby eliciting cancerous responses (Giri

et al., 1995). Oxidative stress induced due to the generation of free radicals and/or

decreased antioxidant level in the target cells and tissues has been suggested to play an

important role in carcinogenesis (Huang et al., 1999). Increased incidence of oxidative

stress and lipid peroxidation are implicated in carcinogenic processes (Khanzode

Khanzode 2004).

Cancer cachexia is a common clinical problem that substantially impacts upon the

quality of life and survival of cancer patients. The pathophysiology of this syndrome

implicates tumour induced metabolic changes and immune response. Clinical

manifestations include anorexia, chronic nausea and change in body image. (Nayak,

2002). Vinblastine isolated from the Catharanthus rosesus (Farnsworth and Blowster,

1967) is used for the treatment of Hodgkins, choriocarcinoma, non-hodgkins lymphomas,

leukemia in children, testicular and neck cancer. Vincristine is recommended for acute

lymphocytic leukemia in childhood advanced stages of hodgkins, lymophosarcoma, small

cell lung, cervical and breast cancer (Farnsworth and Bingel, 1977). Among several

potential benefits of ayurvedic medicine, relief from cancer cachexia is the most valuable.

Herbs used in cancer therapy provide not only total healing, but also reduces the side

effects and cancer associated complications. It also avoids the need for supplemental

therapy to manage cancer. Each herbal product contains multiple active principles that

may operate synergistically, producing therapeutic benefits and lowering the risks on

adverse effects. The anorexia or weight loss could be effectively managed by Withania

somnifera, Sida cordifolia, Asparagu sracemosa, Vitis vinifera, Plumbago zeylenica,

Tinospora cordifolia, Zingiber officinale, Coptidis rhizoma, etc. These herbs have been

shown to improve appetite, food intake, malnutrition, fatigue and sensation of well-being

which could elicit body weight gain. These herbs may even stimulate the flow of digestive

juices, thereby improving digestion and increasing the appetite. Aegle marmelos,

Holarrhena antidysenterica, Punica granatum, Cyperus rotundus, Emblica officinalis, and

Plumbago zeylanica can be used as anti-diarrhoeals when diarrhoea becomes one of the

32

complications of cancer cachexia. Terminalia chebula could be useful against chronic

constipation and digestive disorders which are common in cancer patients resulting in loss

of appetite. Eclipta prostrata, Emblica officinalis, Withania somnifera and Piper longum

can be directed to correct nausea and vomiting (Nayak, 2002). Among the above-

mentioned herbs, Withania somnifera (Agarwal et al., 1999) and Tinospora cordifolia

(Mathew, 1999) are also proven to be powerful immunostimulants, which could increase

body resistance power during cancer associated immuno suppression. The therapy

includes recommendations for lifestyle and use of specific foods and herbs which are very

helpful not only in preventing the progression of the disease but also makes the patients

feel better and comfortable in overcoming the symptoms. Allium sativum (garlic) could be

helpful to manage pain and ache. Bacopa monniera strengthens mental faculties and helps

to manage insomnia or sleeplessness due to stress (Bakhru, 2000). An herbal combination

of Withania sominifera, Asparagus racemosa, Hydrocotyle asiatica, Nardostachys

jatamamsi, Elettaria cardamomum, Tribulus terrestris, Zingiber officinalis and Eclipta

alba could also be useful in the treatment of anxiety, tension and insomnia. Ocimum

sanctum is beneficial against stress and depression during cancer. Curcuma longa,

Zingiber officinale, Glycyrrhiza glabra, Terminalia chebula, Ocimum sanctum and

Adhatoda vasica are used to control cough and shortness of breathe especially for lung

cancer patients (Nayak, 2002). Thus, ayurvedic therapeutic regimen rejuvenates the body

tissues, tones up the systems and act as a tonic to the body against cancer cachexia. This

kind of orientation toward total healing and health promotion makes approach to cancer

therapy promising.

Nutritional supplement and/or diet modification alone may not be sufficient to

control risk of mammary cancer. Thus there is a necessity to combine dietary factors/life

style factors with well known chemopreventive agents and use them in combinations for

cancer prevention. A single chemopreventive agent is unlikely to be effective for the

prevention of cancer. There is convincing evidence that the combination approach does

indeed provide greater efficacy than the administration of individual agent at higher doses.

It really holds better promise to use multiple agents that can hit multiple targets in

carcinogenesis. This particular combination chemoprevention approach is more preferred

33

because: (a) combination treatment can hit more than one critical molecular target, (b)

lower dose requirement lessening the concern of associated toxicities, and (c) acceptability

in human (Larson et al., 2004). Dietary and endogenous antioxidants prevent cellular

damage by reacting with and eliminating oxidizing free radicals. However, in cancer

treatment, a mode of action of certain chemotherapeutic agents involves the generation of

free radicals to cause cellular damage and necrosis of malignant cells. So a concern has

logically developed as to whether exogenous antioxidant compounds taken concurrently

during chemotherapy could reduce the beneficial effect of chemotherapy on malignant

cells. The importance of this concern is underlined by a recent study which estimates 23

percent of cancer patients take antioxidants (VandeCreek et al., 1999). The study of

antioxidant use in cancer treatment is a rapidly evolving area. Antioxidants have been

extensively studied for their ability to prevent cancer in humans (Singh and Lippman,

1998). It was suggested that antioxidants might interfere with the oxidative mechanisms of

alkylating agents (Labriola and Livingston, 1999). Antioxidants have been shown to

increase cell death by this mechanism (Chinery et al., 1997; Mediavilla et al., 1999).

34

List of herbs commonly used in cancer treatment

No. Name of the herb Method and use

1 Vitis vinifera The mixture of Terminalia chebula, grape juice and

sugar cane juice has been used (Hartwell, 1969).

Resveratrol, a natural product derivative from grape

juice has been proved to possess cancer

chemopreventive activity (Jang, 1997).

2 Baliospermum montanum The paste comprising of Baliospermum montanum,

Plumbago zeylanica, Euphorbia neriifolia, Calotropis

procera, jaggery, Semecarpus anacardium applied

over the tumours (Bhishagratha, 1991).

3 Moringa oleifera The paste of Moringa oleifera seeds, Solanum

xanthocarpum, Sinapis dichotoma, Holarrhena

antidysenterica and Nerium odorum roots prepared

with buttermilk is used for arbuda tumours (Murthy.

2001).

4 Ficus bengalensis Application of mixture of Ficus bengalensis and

Saussurea lappa pacify tumour growth on bone

(Murthy, 2001).

5 Curcuma domestica The Curcuma domestica powder in combination with

Symplocos racemosa, Soymida

febrifuga, is mixed with honey and this is used as an

external remedy (Murthy, 2001).

35

Bridelia retusa Spreng.

Plant Description

Bridelia species belong to the family Euphorbiaceae, and comprise approximately

60-70 species distributed in Asia, Africa and Australia. Chemical and pharmacological

studies of Bridelia species have resulted in the identification of flavonoids, sesquiterpenes,

triterpenoids, and phenolic compounds, as well as a wide variety of biological activities

including antiamebic, antianemic, antibacterial, anticonvulsant, anti-diabetic,

antidiarrhoeal, antihelmintic, anti-inflammatory, antimalarial, antinociceptive, antiviral,

and hypoglycemic activities (Ngueyem et al., 2009; Khiev et al., 2010).

Bridelia retusa Spreng (Bridelia airyshawii) is a moderate sized tree or a shrub

belonging to Euphorbiaceae family growing up to 18-20 meters in height with conical

spines 7 cm long when young. Bridelia retusa (airyshawii) commonly known as Asana,

36

Kasai or Khaja is a shrub, found to be distributed through out the hotter parts of India. The

tree is dioceious with leaves 7.5- 15 cm long, simple, alternate, ovate, elliptic or oblong

acute or acuminate, pubescent and with prominent veins, and are used as fodder. Stem is

armed and the dark grey bark is used for tanning (Tatiya et al., 2011 and Shahid et al.,

2009). The flowers are greenish yellow in color with lateral appearing from May to July

(Jain S. K., Pal D. C. 1982). Flowers are in axillary spikes, small and unisexual (Shahid et

al., 2009). Fruits drupes, 5 mm in diameter, and edible, purple black in color and contains

a single, 5 mm in diameter, reddish brown seed. Fruit ripens in December to January (Jain

and Pal, 1982). The seeds have brownish papery testa and 1 or 2 seeds with fairly thick

bony shells.

Synonyms and classification (Jain and Pal, 1981; Trease and Evans, 2008)

Synonyms Classification

Hindi Khaja Kingdom Plant

Kannada

Malayalam

Asana

Kukaryim

Division

Phylum

Angiosperms

Dicotelydon

Marathi

Sanskrit

Tamil

Telugu

Kantakauchi

Mahavira

Mulluvengai

Bontayegi

Subclass

Order

Family

Archichlamydae

Geraniales

Euphorbeaceae

37

Habitat and Ecology

The species are found growing throughout India; in Southeast Asia usually have

primary and secondary forest vegetation either as big trees or as smaller trees or shrubs. It

is found to be growing throughout India up to an altitude of 1,000 m except in very dry

regions (Banerjee and Kulkarni, 2009), in Himalayas from Nepal to the hills of Assam,

Meghalaya, Manipur, Arunachal Pradesh, and also in South-India and Sri Lanka (Tatiya et

al., 2011; Shahid et al., 2009).

Medicinal Properties

Various plants from this family have been investigated for their medicinal

properties. B. retusa and B. ferruginea are known to contain compounds that possess

antifungal and anti-inflammatory properties (Jayasinghe et al., 2003; Olajide et al., 2003).

The roots and bark of Bridelia species have been used for the treatment of headache,

abnormal pain, indigestion, astringent, and purgative (Mostafa et al., 2006). Previous

studies on Bridelia species have reported the occurrence of sesquiterpenes, megastigmane

glucosides in B. glauca (Sueyoshi et al., 2006), flavonoids in B. ferruginea and B.

tomemtosa (Addae-Mensah and Achenbach, 1985; Hui, et al., 2006), phenolic derivatives

in B. ferruginea B. retusa and B. ndellensis (Cimanga et al., 1999; Jayasinghe et al., 2003;

Mostafa et al., 2006), and triterpenoids in B. monoica, B. tomemtosa and B. ovata (Hui

and Fung, 1968; Boonyaratavej, 1990; Boonyaratavej et al., 1992) as the chemical

constituents, as well as biological activities including snake venom phosphodiesterase-I

inhibitory (Mostafa et al., 2006), antibacterial (Ramesh et al., 2001), and antifungal

(Jayasinghe et al., 2003) activities. The LD50 of the B. retusa (EE4965000) administered

by i.p. was observed as 1 gm/kg when investigated in mice (CSIR, 1971).

Plant pacifies vitiated vata, pitta, diarrhea, dysentery, hemorrhoids, hemorrhage,

menorrhagia, leucorrhea, arthritis, diabetes, wounds, ulcers and poison. Plant also has

contraceptive action. Decoction of stem bark with country liquor is used for diarrhea, ear

38

ache and prevents pregnancy. Extract from the stem bark has antiviral, anticancer and

hypotensive properties. Paste of the stem bark is applied to wounds and bark juice taken

internally in case of snake bite (Joshi, 2006). Bridelia retusa is used in the indigenous

system of medicine for treatment of rheumatism and as an astringent and it also pacifies

vitiated vata, pitta, diarrhea, dysentery, hemorrhoids, hemorrhage, menorrhagia,

leucorrhea, arthritis, diabetes, wounds, ulcers and poison (Shahid et al., 2009). A survey

of ethno medicinal records revealed that the bark is pungent, bitter, heating; useful in

‘vata’ lumbago, hemiplegia. The bark is good for the removal of urinary concretions .The

root and the barks are valuable astringents. The bark is used as a liniment with gingerly oil

in rheumatism (Banerjee and Kulkarni, 2009). The bark extract is used by the tribal to

develop sterility and it is used as a contraceptive. One or two drops of fruit extract are

poured in ear to cure earache (Tatiya et al., 2011). Bark is a valuable astringent and used

in the form of a liniment in rheumatism. It exhibited antiviral, hypoglycemic, hypotensive,

antifertility activity and removal of urinary concretions properties in pharmacological

trials. It is reported as anti inflammatory activity in animal model (Mehare and Hatapakki,

2003; Tatiya et al., 2011). Earlier work was reported for wound healing activity on leaves

of Bridelia retusa (Udegbunam et al., 2011).

Phytochemical analysis has revealed the presence of steroids, triterpenoids, tannins

and flavonoids as major constituents by Tatiya et al. (2011). The presence

phytoconstituents reported by Banerjee and Kulkarni (2009) includes steroids,

carbohydrates, flavanoids, tannins, phenols, glycosides triterpenoids and saponins while

absence of alkaloids, reducing sugar, proteins, amino acids, gums and resins were

detected. The bark of Bridelia retusa was screened for estimation of phytochemical

standards like: phenolic, flavonoid, tannins, carbohydrates and mucilage content. In

addition to its acetone fraction i.e. tannins rich fraction, were also subjected to in vitro

antioxidant activity using standard procedures. The effects of extracts of Bridelia

ferruginea on Bacillus subtilis, Eschericia coli, Staphylococcus aureus, Aspergillus niger

and Fusarium solani were examined and the results revealed that methanol extract was the

most effective on Bacillus substilis and Escherichial coli while ethanol extract was most

effective on Staphylococcus aureus. In the fungal isolates the ethanol extracts had the

39

highest growth inhibition though the values obtained were considerably lower than those

of the control experiments (Jose and Kayode, 2009).

Phytochemical standards analysis of B. retusa revealed the presence of bioactive

components comprising phenolics (2.92-3 g of GAE/100 g of dry sample), total tannins

(33-43 % w/w as tannic acid equivalence), proanthocyanidin content (2.98-4 % w/w as

catechin equivalent), ellagic acid (0.135 % w/w), mucilage (3-4 % w/w), flavonoids (257

mg of Rutin equivalence/100 g dry plant) and carbohydrates (7 – 7.1g /100g of plant). The

acetone exhibited IC50 values of 47.20, 110.76, 48.81 44.15 and 50.42 μg/ml, respectively

in DPPH (1,1 Diphenyl-2-picryl-hydrazyl free radical scavenging activity), ALP (anti-

lipid peroxidation effect), hydroxyl, hydrogen peroxide and nitric oxide radical inhibition

assays while acetone had effective reducing power. The results showed that tannins rich

fractions of bark had strong antioxidant activity by inhibiting DPPH, ALP, reducing

power, hydroxyl radical and hydrogen peroxide and nitric oxide scavenging. These results

suggest strong antioxidant potentials of the acetone extracts of Bridelia retusa. These

bioactive compounds may be responsible for antioxidant properties of B.retusa that form

the basis of their use in herbal medicine in India (Tatiya and Saluja, 2010).

Extract of Bridelia retusa leaves was investigated as corrosion inhibitor of mild

steel in 1 N H2SO4 using conventional weight loss, electrochemical polarizations,

electrochemical impedance spectroscopy and scanning electron microscopic studies. The

weight loss showed that the extract of Bridelia retusa leaves had excellent corrosion

inhibitor and electrochemical polarizations data revealed the mixed mode of inhibition.

While the results of electrochemical impedance spectroscopy showed that the change in

the impedance parameters, charge transfer resistance and double layer capacitance, with

the change in concentration of the extract was due to the adsorption of active molecules

leading to the formation of a protective layer on the surface of mild steel. Scanning

electron microscopic studies provided the confirmatory evidence of improved surface

condition, due to the adsorption, for the corrosion protection (Patel et al., 2010).

40

List of antifugal sesquiterpenes reported from B. retusa (Jayasingh et al., 2003).

In certain studies carried out using aqueous and alcohol extracts of the bark of

Bridelia retusa (Linn.) Spreng (Euphorbiaceae) were investigated for acute anti-

inflammatory activity in carrageenan-induced rat paw oedema. Both the extracts exhibited

significant dose-dependent inhibition of rat paw oedema in dose of 50 mg/kg, orally and

100 mg/kg, orally, when compared to control group. The activity was compared with a

standard drug, diclofenac (15 mg/kg, orally) sodium (Mehare and Hatapakki, 2003).

Wound healing property of B. ferruginnea has been reported with significantly enhanced

41

wound contraction and epithelization (Udegbunam et al., 2011). Aqueous and alcoholic

extracts of its bark were investigated earlier for acute antiinflammatory activity in

carrageenan-induced rat paw oedema (Tatiya et al., 2011).

Antifertility activity of previous investigation of ethyl acetate and methanol

extracts of Aegle marmelos and Bridelia retusa and isolation of alkaloids from A.

marmelos and fatty acids and flavonoid from B. retusa (Gurulingappa, 2002, 2005, 2009).

In the type 2 diabetic model rats, the ethanol extract of stem bark of Bridelia ndellensis

showed an anytihyperglycemic effect comparable to that of glibenclamide when fed

simultaneously with glucose (Sokeng et al., 2005). The results of this study suggest that

Bridelia ferruginea bark extract achieved a reduction in plasma glucose levels especially

in glucose induced hyperglycemic rats. This implies that the methanol extract has anti-

diabetic properties and may thus be useful in the management and treatment of diabetes

mellitus (Kolawole et al., 2006). The methanolic stem bark extract of B. grandis, has

hypoglycaemic effects in type 2 diabetic mice (Njamen et al., 2011). The ethanolic

extracts of six plants including Bridelia ovate showed cytotoxic activity against lung and

prostate cancer cell lines (Saetung et al., 2005). B. cambodiana Gagnep. methanolic

extract was found to be cytotoxic against HL-60 cell line (Khiev et al., 2009).

In Pharmacological trials the bark of Bridelia retusa exhibited anti-viral,

hypoglycemic and hypotensive properties. According to Ayurveda, the bark is good for

removal of urinary concretions, useful in lumbago and hemiplegia. The bark is used as

liniment with gingelly oil in rheumatism (Kirtikar and Basu, 1999). The bark is

documented to be used ethno botanically to promote antifertility. The presence of

triterpene ketone (4- desmethyl eupha 7, 24 (28) - diene-3-one) in the bark has been

reported and also contains 16-40% of tannins (Chopra and Nayer, 1992). Phenolics

including tannins are the natural products present in abundant amount and possess various

biological properties related to antioxidant mechanisms (Christel et al., 2000). The bark of

B. retusa exhibited variations in their contents of phytoconstituents depending upon the

geographical location from where they were collected which was evident and supported

from their extractive values and total polyphenol content. The methanolic extract of the

42

plant collected from Maharashtra and Andhra Pradesh regions and the plant collected from

the region of Maharashtra was found to be superior with respect to extraction yield and

radical scavenging activity. These differences may possibly be related to the natural

climatic differences which occur over a particular geographical area to be influenced by

several climatic factors (Banerjee and Bonde, 2011). Therefore, the need to investigate the

pharmacological properties of this plant becomes necessary Hence, the present

investigation was undertaken to elucidate phytochemical and pharmacological

investigation of stem bark extract of Bridelia retusa S. with emphasis on qualitative

phytochemical screening, antimicrobial, antihelminthic, invivo antioxidant,

hepatoprotective, nephroprotective, antidiabetic and anticancer activity of the stem bark

extracts.