1

Biological, Pharmacological and Therapeutic Activities of Kigelia africana1

(Lam.) Benth2

Sunday Ene-Ojo Atawodi * and Olufunsho Dayo Olowoniyi3

Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria4

Abstract5

Occurring widely in Africa and beyond is Kigelia africana Benth, a medicinal plant with several6

attributes and considerable potentials. Various parts of the plant are used locally to treat cancer,7

ulcer, gynecological disorders, genital infections, skin diseases, diabetes, epilepsy, bacterial and8

fungal infections as well as being used as cosmetics to enhance beauty. The antioxidant and anti-9

inflammatory properties of some parts of the plant have also been reported. Phytochemical10

analyses revealed the presence of naphthaquinones such as lapachol, kigelinol and isopinnatal in11

the root and iridoids such as specioside, verminoside and minecoside in the stem bark, while the12

leaves are reported to be rich in hydrocarbons like n-hentriacontane, 1-tricosene and esters like13

pentafluoroheptadecyl ester. The fruits are reported to contain iridoids such as jiofuran,14

jioglutolide and ajugol as well as flavonoids and steroids. Toxicological evaluation showed that15

the LD50 for the ethanolic extracts of the fruit and stem bark are 1.3g/kg and 4g/kg respectively,16

while the methanolic extract of the fruit had an LD50 of 3.98g/kg. A 50% methanol-water extract17

of the leaf gave an LD50 greater than 3g/kg. In this review we provide an up-to-date information18

on the established biological, pharmacological and toxicological properties as well as19

phytochemicals responsible for these activities in Kigelia africana.20

Keywords: Kigelia africana; sausage tree; Bioactive compounds; Biological activity;21Toxicological effects22

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1.0 Introduction25

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Kigelia africana (syn. Kigelia pinnata, Kigelia aethiopica) is commonly called sausage or26

cucumber tree because of its huge fruits. It belongs to the Bignoniaceae family. Due to its wide27

occurrence, it has vernacular names in many African languages: Rawuya (Hausa); Uturubein28

(Igbo); Pandoro, Iyan (Yoruba); Bechi (Nupe); Mwegea (Swahili); Umfongothi (Zulu) [1, 2] and29

Ebie in Igala. In Hindi it is known as Balmkheera [3]. Kigelia africana occurs throughout30

tropical Africa. It grows particularly well in wetter areas, spreading across the wet savannah and31

riverine areas [3].32

33

The tree can grow up to 20m tall. It is evergreen where rainfall occurs throughout the year, but34

deciduous where there is a long dry season. The leaves are opposite or in whorls of three, 30-35

50cm long, pinnate, with six to ten oval leaflets up to 20cm long and 6cm broad; the terminal36

leaflet can be present or absent. The flowers (and later the fruit) hang down from branches37

on long flexible stems. Flowers are produced in panicles; they are bell-shaped, orange to reddish38

or purplish green and about 10cm wide. Individual flowers do not hang down but are oriented39

horizontally, some birds are attracted to these flowers and the strong stems of each flower make40

ideal footholds. Their scent is most notable at night indicating their reliance on pollination by41

bats, which visit them for pollen and nectar [4].42

43

Kigelia africana is characterized by its huge fruits which can weigh between 5 to 10kg [5]. The44

fruit is a woody berry from 30 – 100cm long and up to 18cm broad, hanging down on rope-like45

peduncles [4]. The fruit is indehiscent, with woody wall and heavily marked with lenticels at the46

surface. It is grey-brown and many seeded when matured. Seeds are ovoid, ca. 10mm x 7mm47

with leathery testa, embedded in a fibrous pulp. The fruit is eaten by several species of48

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mammals, including baboons, bush pigs, savannah elephants, hippopotami, monkeys and49

porcupines. The seeds are dispersed in their dung. The seeds are also eaten by parrots and brown-50

headed parrots, and the foliage by elephants and greater kudu [4].51

52

This review on Kigelia africana is patterned into biological activities such as antiprotozoal,53

antibacterial, antifungal activities; pharmacological properties such as anti-inflammatory and54

analgesic, anticancer, antidiarrhoeal, anti-ulcer effects as well as toxicological effects with the55

responsible phytochemicals.56

57

2.0 Uses of Kigelia africana in traditional medicine and their pharmacological evaluation58

2.1 Anti-protozoal activity59

One of the several uses of Kigelia africana is for treating malaria. In-vitro studies revealed the60

efficacy of hexane, dichloromethane, ethyl acetate and ethanol extracts of the root bark against61

Plasmodium falciparum [6] and Trypanosoma brucei brucei and T.b. rhodesiense [3], the62

causative organisms for malaria and sleeping sickness respectively. The growth of Entamoeba63

histolytica was also inhibited by the stem bark butanol extract [7]. Four compounds that64

exhibited significant anti-plasmodial activity were isolated from the ethyl acetate extract of65

Kigelia Africana. Three of the four compounds showed good activity against all the different66

parasite strains, the chloroquine-resistant W-2 and two field isolates of Plasmodium falciparum,67

with IC50<5µM. Specicoside exhibited the highest activity on W-2 (IC50=1.5µM) followed by68

2β, 3β, 19α-trihydroxy-urs-12-en-28-oic acid (IC50=1.60µM) and atranorin (IC50=4.41µM) while69

p-hydroxycinnamic acid was the least active (IC50=53.84µM) [6]. Lapachol in the methanol70

extract of the root and another compound (aquinone) obtained from the wood show anti-malarial71

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activity [3]. In a study of the anti-amoebic activity of the butanol extract of the stem bark, three72

known iridoids, specioside, verminoside and minecoside were isolated, purified and identified to73

be responsible. Verminoside exhibited two fold anti-amoebic activities as compared to the74

standard drug while specioside showed comparable activity with metronidazole [7]. The anti-75

trypanosome activity of the stem bark and root bark extracts are attributed to 2-(1-hydroxyethyl)-76

naphtho-[2,3-b]-furan-4,9-quinone and three naphthoquinoids: isopinnatal, kigelinol and77

isokigelinol [3].78

79

2.2 Antibacterial and antifungal activities80

Various parts of Kigelia africana are employed to treat bacterial and fungal infections. In a study81

to verify these properties, crude extracts of stem bark and fruits were prepared with distilled82

water, ethanol or ethyl acetate. In the microtitre plate bioassay, the stem bark and fruit extracts83

showed similar antibacterial effects against Gram-negative and Gram-positive bacteria. A84

mixture of three fatty acids exhibiting antibacterial effects was isolated from the ethyl acetate85

extract of the fruits using bioassay-guided fractionation. Palmitic acid was the major antibacterial86

compound in this mixture thus supporting the traditional use of the plant in therapy of bacterial87

infections [3]. A biologically monitored fractionation of the methanolic extracts of the root and88

fruits led to the isolation of the naphthoquinones, kigelinone, iso-pinnatal, dehydro-α-lapachone89

and lapachol and the phenylpropanoids, ρ-coumaric acid and ferulic acid as the compounds90

contributing to the observed antibacterial and antifungal activities [4].91

92

In another antibacterial and antifungal study using the agar diffusion technique, Owolabi and co-93

workers reported that like amoxillin standard antibiotics, crude ethanolic extract exhibited94

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antibacterial and antifungal activities against Staphylococcus aureus and Candida albicans with95

zones of inhibition measuring 15.0±0.95 and 20.75±4.6mm respectively but the aqueous extract96

exhibited no antibacterial or antifungal activity. The minimum inhibitory concentration for the97

ethanol extract was found to be 6.25±1.07mg/ml for S. aureus and 7.92±1.52mg/ml for C.98

albicans. In another report, it was also established that the stem bark extract inhibited a number99

of harmful micro-organisms, including Escherichia coli (responsible for abscesses),100

Pseudomonas aeruginosa(which causes skin sepsis and infections), Staphylococcus aureus101

(which causes impetigo and skin abscesses) and Candida albicans, a fungal organism that causes102

thrush [4]. Similarly, evaluation of the antibacterial activities of ethanolic and aqueous extracts103

of Kigelia africana fruit against multi drug resistant Pseudomonas aeruginosa, both ethanolic104

and aqueous extracts showed antibacterial activity, with the ethanolic extract showing more105

potency [8-10].106

107

2.3 Anti-inflammatory and analgesic activity108

The use of the bark, stem, twigs, leaves and fruits of Kigelia africana to relieve rheumatism,109

tooth and headache has been documented [3, 11]. Picerno and co-workers [12] reported that the110

anti-inflammatory property of Kigelia africana fruit polar extract was due to the constituent111

verminoside which is known to cause significant anti-inflammatory effects inhibiting both iNOS112

expression and NO release in the LPS-induced J774.A1 macrophage cell line [12].113

114

The ethanolic extract of the stem bark has been evaluated for analgesic property using acetic acid115

induced mouse writhing and hot plate reaction time; and anti-inflammatory property using the116

carrageenan-induced paw oedema. The extract showed a dose dependent significant reduction of117

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the number of writhes (p<0.001) with 500mg/kg body weight dose giving the highest reduction.118

The extract showed an insignificant elongation of the hot plate reaction time (p>0.05). In the119

carrageenan-induced paw oedema, a dose dependent significant inhibition was observed120

(p<0.001) between the second and the fifth hour, confirming that the ethanolic stem bark extract121

has significant analgesic and anti-inflammatory properties. Inhibition of the synthesis of122

prostaglandins and other inflammatory mediators has been suggested to be responsible for the123

analgesic and anti-inflammatory properties [13].124

125

2.4 Anti-diarrhea activity126

One important local use of Kigelia africana is the use of the leaf for treating diarrhea. Scientific127

evaluation showed that administration at a dose of 100 or 200mg/kg of aqueous leaf extract to128

experimental animals caused anti-diarrhea activity, as evidenced by the reduced fecal output in129

castor oil – induced diarrhea in animals and remarkably decreased the propulsive movement of130

the gastro-intestinal contents [14]. On the isolated guinea pig ileum, the extract did not131

appreciably affect acetylcholine and histamine induced contractions. In an antidiarrheal activity132

studied in vivo using castor oil to induce diarrhea in rats and in vitro using isolated jejunum, 500133

and 1000mg/kg ethanol root extract significantly reduced the frequency of diarrheal stool and the134

spontaneous propulsive movement of isolated jejunum. Kigelia africana root extract also135

produced reversible inhibition of acetylcholine induced mobility of isolated rabbit jejunum. The136

observed spasmolytic effects of the extract may explain its continual use in the management of137

chronic abdominal pains associated with diarrhea [2] The intra-peritoneal LD50 of the extract in138

mice was estimated to be 785.65±24 mg/kg [15].139

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2.5 Anti-diabetic and antioxidant activities141

Like many other African food [16, 17] and medicinal plants [18 – 20], the use of Kigelia142

africana to manage diabetes is traditionally practiced and reported [2,3]. A decoction of the dried143

fruit is made by boiling in water for an hour. The anti-diabetic activity and the antioxidant effect144

were studied [21]. Also, in a polyherbal preparation, ADD-199, Kigelia africana is in145

combination with three other plants: Maytenus senegalenses, Annona senegalenses and Lannea146

welwitchii. The anti-diabetic and antioxidant effects were investigated in streptozotocin-induced147

diabetic C3H mice and results compared with two allopathic hypoglycaemic drugs,148

glibenclamide and metformin. Plasma glucose, insulin and lipids as well as liver glycogen and149

lipid peroxidation were measured following treatment for eight weeks. The results indicated that150

plasma insulin levels in normal controls at termination were about 76µmol/L compared to trace151

levels in untreated diabetic mice. Like glibenclamide, ADD-199 increased insulin levels in152

diabetic mice up to 70% of levels in untreated non-diabetic mice whilst metformin had no effect.153

Also, basal plasma glucose levels in diabetic controls (18.8 mM) were reduced to 14.0 mM by154

100 mg/kg ADD-199 in < 2 weeks compared to 4 to 6 weeks for glinbenclamide and metformin,155

respectively. This hypoglycaemic effect of ADD-199 was associated with the alkaloidal content156

of the extract. Treatment with ADD-199 or the hypoglycaemic agents reversed the observed157

elevation in plasma lipids but increased hepatic glycogen, triacylglycerol and cholesterol levels.158

Treatment also increased hepatic glucose uptake by isolated diaphragms and attenuated hepatic159

lipid peroxidation. These antihyperglycaemic and antioxidant actions of ADD-199 was160

comparable to those of the maximum daily therapeutic doses of glibenclamide (0.25 mg/kg) and161

metformin at 50 mg/kg [21].162

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Olaleye and Rocha, [22] carried out an in-vitro assessment of the antioxidant property of Kigelia164

africana extracts in rat liver homogenate. Increased formation of thiobarbituric acd reactive165

substances (TBARS) was stimulated by different pro-oxidants: 10µM iron (II) sulphate, (FeSO4),166

5µM sodium nitroprusside (SNP), and 2mM 3-nitropropionic acid administered, which indicates167

lipid peroxidation in the liver. Administration of Kigelia africana statistically (p<0.05) reduced168

the production of TBARS in a concentration-dependent manner in all the pro-oxidant-induced169

oxidative stress, suggesting that the use of the plant in the treatment of various diseases,170

especially liver diseases could be due to its ability to act as an antioxidant [22]. Saini and co-171

workers [3] attributed the antioxidant potential of Kigelia africana to caffeic acid derivatives and172

other compounds unique to the plant.173

174

2.6 Anti-ulcer effect of Kigelia africana175

The use of Kigelia africana fruit, bark and root to treat ulcer has been reported [3]. Owolabi and176

Nworgu [23] investigated the anti-ulcer activity of the ethanol extract of Kigelia africana stem177

bark in Wistar albino rats. In both preventive and curative models of ulcer respectively induced178

by absolute ethanol and indometacin, the extract caused marked inhibition of ulceration,179

suggesting a dose-dependent gastro-protective effect by the plant in the two models of ulcer [23].180

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2.7 Toxicity of Kigelia africana parts184

2.7.1 Acute toxicity185

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Acute toxicity tests of the fruits indicate they are non-toxic [2]. In a study on the diuretic activity186

of aqueous extract of the bark in experimental rats, Sharma and colleagues [24] reported that it187

was safe up to 5g/kg. A determination of acute toxicity of the methanol fruit extract using male188

Sprague Dawley rats showed that the extract was well tolerated by the animals as there were no189

observable signs of acute toxicity effects like restiveness, seizure or dizziness after the190

administration of 400mg/kg. However at 6400mg/kg, the animals showed signs of toxicity like191

jerks and writhes with 60% death. At 12,800mg/kg there was 80% death of the animals. The192

LD50 was estimated from a log-dose curve to be 3,981.07mg/kg [25-27]193

194

In another study using paracetamol (acetaminophen)-induced liver toxicity model, administration195

of 100mg/kg aqueous extract counteracted the effects of paracetamol on levels of aspartate196

transaminase (AST), alanine transaminase (ALT), superoxide dismutase (SOD), catalase (CAT),197

gluthathione peroxidase (GPx) and δ-aminolevulinate dehydrogenase (δ-ALA-D), suggesting198

that it can act as hapato-protective agent against toxicity possibly through its antioxidant action199

[22].200

201

2.7.2 Sub-chronic and chronic toxicity202

The sub-chronic toxicity of the aqueous anti-diabetic polyherbal extract ADD-199 containing203

Kigelia africana and three other plants which was administered at a daily dose of 100 or 500204

mg/kg body weight over 30 days, to male Wistar albino rats appeared to show no effect on many205

haematological, urinary and plasma biochemical parameters as well as on some modulators of206

some hepatic cytochrome P450 (CYP) isozymes normally measured as indices of organ specific207

toxicity or potential for drug interactions. Specifically ADD-199 containing Kigelia africana did208

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not affect plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline209

phosphatase (ALP) and albumin or creatinine kinase (CK) levels. It also did not affect plasma210

creatinine and urea levels. Furthermore, ADD-199 neither affected packed cell volume (PCV),211

nor red blood cells (RBC), reticulocytes, platelets, lymphocytes and granulocyte levels. It212

however, caused significant dose-dependent reductions in white blood cell counts at day 15 with213

varying degrees of recovery by day 30. Also, it reduced the rate of body weight increases after214

week 3. However, no changes were observed in organ weight at termination. The ADD-199 did215

not significantly affect zoxazolamine-induced paralysis and pentobarbital-induced sleeping times216

as well as certain CYP isozyme activities in rats, suggesting that ADD-199 had no overt organ217

specific toxicity and did not demonstrate a potential for drug interactions via CYP-mediated218

metabolism in rats following sub-chronic administration [26].219

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The protective effect of methanol extract of Kigelia africana fruit extract against cisplatin-221

induced renal toxicity in male rats has been studied [27]. Whereas over 28 days, cisplatin-treated222

rats suffered loss in body weight, elevation in blood urea nitrogen and serum creatinine levels as223

well as tubular necrosis, pre-treatment with Kigelia africana fruit methanol extract as a224

prophylaxis significantly prevented these changes. Though post-treatment of animals with the225

extract after cisplatin treatment did not completely restore serum catalase activity, it caused some226

alleviating effects, suggesting that Kigelia africana fruit extract may protect against cisplatin-227

induced renal toxicity, and hence might serve as a novel agent to limit renal injury [27].228

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2.7.3 Cytotoxic activity230

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The cytotoxicity of hexane, chloroform, ethyl acetate, ethanol and methanol extracts of different231

parts of Kigelia africana has been studied on Artemia salina using the brine shrimp lethality test232

(BSLT). Some workers [28] have reported moderate toxicity of the ethanol extract of the root233

and fruit at a dosage of 593 and 124µg/ml respectively while the ethyl acetate extract of the fruit234

was also moderately toxic at 495µg/ml. Other workers [11, 28, 29] reported a moderate235

cytotoxicity of ethanol extract of the fruit to Artemia salina at a dosage of 1000µg/ml.236

237

2.8 Molluscidal and piscicidal effects238

The molluscidal and piscidal effects of the aqueous extract of Kigelia africana bark has been239

reported [25]. In a study to evaluate the piscicidal effect of Kigelia africana aqueous bark extract240

against Clarias gariepinus fingerlings, graded concentrations of the extract, 40,80,120ppm were241

prepared into which twenty fingerlings were added in replicates. The toxicity test lasted 24242

hours during observations were made at 1, 2, 4, 8, 12, 16, 20 and 24 hours. Varying degrees of243

mortality was recorded, with 100% death after 4 hours in the tank of 120ppm concentration and244

the causative agent identified as coumarins.[30] Table 1 summarizes the toxic effects of Kigelia245

africana extracts on different species of animals.246

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2.9 Anticancer activity of Kigelia africana parts249

There are many reports in literature suggesting the use of Kigelia africana to either prevent or to250

treat cancer [4, 30, 31]. In a study to determine the effect of Kigelia africana seed oil on cell251

proliferation in culture, human colon adenocarcinoma (Caco-2) and human embryonic kidney252

(HEK-293) cells were maintained and treated with various concentrations (0, 20, 40, 80, 100 and253

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120mg/l) of Kigelia africana seed oil. The trypan blue dye exclusion method was used to254

determine cell growth 48 hours after oil treatment. The seed oil suppressed both Caco-2 and255

HEK-293 cell growth in a dose dependent manner. The seed oil did not cause increase cell death256

as the number dead cells remained unchanged under control and oil-treated conditions. The oil257

significantly suppressed Caco-2 cell growth compared to HEK-293 cell growth at all oil258

concentrations. The suppression of Caco-2 and HEK-293 cell proliferation by Kigelia africana259

seed oil suggest a potential antiproliferative effect of the oil on the two cell lines [11]260

Methanolic extract of the root of Kigelia africana contains the constituent lapachol [30] which is261

reported to be effective in the treatment of solar keratosis, skin cancer and Kaposi sarcoma, an262

HIV-related skin ailment [31]. Serial dilutions of standardized aqueous, ethanol and263

dichloromethane extracts of the stem bark and fruits of Kigelia africana were tested for their264

growth inhibitory effects against four melanoma cell lines and a renal cell carcinoma line (Caki-265

2) using two different assays (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide,266

MTT and Sulforhodamine B, SRB assays). Lapachol, a possible constituent of these extracts,267

together with known therapeutic anti-neoplastic agents evaluated this way, showed significant268

inhibitory activity of the dichloromethane extract of the stem bark and lapachol in a dose-269

dependent and time-dependent manner. Chemosensitivity of the melanoma cell lines to the stem270

bark was greater than that seen for the renal adenocarcinoma line, but in marked contrast271

sensitivity to lapachol was similar amongst the five cell lines, suggesting that lapachol is the272

active ingredient that exhibit anti-cancer property.273

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2.10 Effect on the Central Nervous System276

Among the variety of uses of Kigelia africana is in the treatment of epilepsy, CNS stimulating277

activity and as antidotes against snake poisons. Snake bite antidotes are made with an infusion of278

the fruits, stem, leaves, twig or bark taken orally or rubbed onto the bite [2]. The CNS stimulant279

activity of the ethanolic stem bark extract has been verified [9]. The barbiturate induced sleeping280

time and the Rota rod bar were used to study the effect of the extract on muscle coordination in281

mice. The results showed that the extract at all doses tested reduced the duration of sleeping time282

when compared to the control group that received distilled water. This difference in sleeping283

time was significant (p<0.0001 at all doses tested) and was found to be dose dependent. Its effect284

was also compared with caffeine (a known stimulant) and the extract gave a shorter duration of285

sleeping time compared to caffeine (p<0.05 at 400 mg/kg dose) indicating better stimulant286

properties. In comparison with diazepam, the extract at all doses tested also gave a statistically287

significant shorter duration of sleep (p<0.0001). On the Rota rod, the extract had no sedative288

effect as the animals maintained their balance on the rod through the entire period of the289

experiment [25].290

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2.11 Effects on animal reproductive organs and reproductive system292

In traditional medicine, sexual complaints such as infertility, poor libido, sexual asthenia and293

impotence are treated with herbal prescriptions containing the fruit, roots or leaves of Kigelia294

africana. A small amount of unripe fruit is chewed or an aqueous preparation of the fruit is taken295

orally as a sexual stimulant, and the intoxicating traditional beer to which they are added is drunk296

as an aphrodisiac [5]. The fruits are also applied on the breast to improve flow of milk in297

lactating women [3]. Kigelia africana fruit aqueous extract has been successfully used as fertility298

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enhancing agent in rats [32]. The steroidal components are thought to enhance reproductive299

ability since steroids as androgen and estrogen have shown to contain fertility properties300

necessary for the improvement and production of reproductive organs [33]. A study to301

investigate the effects of varying dietary supplementation of Kigelia africana on the sperm302

quality and fertility in African catfish, Clarias gariepinus showed that dietary inclusion of the303

plant positively affected some parameters of sperm quality in the fish, with increases in sperm304

counts, percentage motility, milt volume and motility duration [33].305

306

2.12 Use as cosmetics307

Traditionally, Kigelia africana is used as cosmetic to enhance beauty [5]. Some preparations308

contain extract of one or more parts of the plant, mainly the fruit, stem bark or the pendulum309

(where the fruit hangs from, or a product thereof). Typically, the preparation contains 50%310

extract mixed with carrier, excipients and colorants (SumobrainTM). Aqueous or alcohol extracts311

are ideal for water based cosmetic products such as gels, lotion, water or oil emulsions and312

creams. The products are used to make anti ageing and regenerating skin care products, skin313

tightening cosmetics such as bust firming products. Anti-inflammatory, antioxidant and314

antibacterial agents are other products that are commercially made from Kigelia Africa315

(PhytoTrade Africa).316

317

2.13 Diuretic activity318

The diuretic activity of Kigelia Africana aqueous bark extract was investigated by the319

determination of urine volume, electrolyte concentration and diuretic potency in male albino rats.320

Different concentrations of the extract, 250 and 500mg/kg were orally administered to hydrated321

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rats and their urine output was immediately measured after 5 hours of treatment. Fusemide322

(10mg/kg) was used as reference drug while normal saline (0.9%) solution was used as control.323

The result showed that the bark extract exhibited dose dependent diuretic property. The onset of324

diuretic action was within 1 hour and lasted up to 5 hours, with 500mg/kg displaying a potency325

of 0.8 and 250mg/kg gave 0.32. The extract also caused a marked increase in Na+, K+ and Cl-326

labels. The result suggests that the aqueous extract possess significant diuretic activity, justifying327

its use in folk medicine.328

329

3.0 Nutritional value of Kigelia africana330

Kigelia africana provides a nutritious source of food during times of famine when the seeds are331

roasted to eat. The fruit and bark are used in the brewing process to aid fermentation and enhance332

the flavor of traditional beer. The fruit pulp is not edible as it may cause blistering of the tongue333

and skin. However, fallen fruits along with leaves and flowers are browsed or foraged by334

livestock and game [5]. In a study of the effect of Kigelia africana fruit meal (KAFM) on sperm335

quality of African catfish, Clarias gariepinus, the KAFM supplement may have enhanced336

nutrient utilization which is reflected by improvement in weight gain by testes [33].337

338

The pro-fertility effect of dried fruit meal (KAFM) was investigated on reproductive339

performance of female Clarias gariepinus fed with increasing levels for 90 days in relation to340

egg production and quality (number, shape, structure, fecundity) and hatchability (%341

fertilization, % hatching, % survival). The decrease in % deformity in hatchlings of Clarias342

gariepinus fed dietary KAFM compared with the control diet suggest that KAFM improves the343

quality of larvae. The highest % survival of hatchlings was recorded in the fish fed with dietary344

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KAFM (100g KAFM/kg diet). Egg sizes for fish fed the control diet and dietary levels revealed345

no significant difference in egg size. The result showed that dried KAFM had greater fertility on346

male than on female Clarias garipinus [34].347

348

4.0 Chemical Constituents of Kigelia africana349

The large occurrence of secondary metabolites in different parts of Kigelia africana is350

responsible for its several medicinal applications. These compounds include naphthaquinones,351

iridoids, sterols, coumarins, flavonoids and alkaloids among others [3, 13, 35]. Structures of352

isolated compounds have been characterized and identified using gas chromatography,353

ultraviolet spectroscopy, infrared spectroscopy, nuclear magnetic resonance and other354

spectroscopic techniques like, mass spectrometry, or gas chromatography-mass spectrometry.355

The use of Kigelia africana in traditional African medicines has been verified by corresponding356

pharmacological properties.357

358

4.1 Chemical constituents of Kigelia africana fruit359

Gouda and colleagues [36] reported that a new furanone derivative formulated as 3-(2'-360

hydroxyethyl)-5-(2''-hydroxypropyl) dihydrofuran-2-(3H)one and four new iridoids named: 7-361

hydroxyviteoid II, 7-hydroxyeucommic acid, 7-hydroxy-10-deoxyeucommiol and 10-362

deoxyeucommiol have been isolated from the fruits in addition to seven known iridoids namely,363

jiofuran, jioglutolide,1-dehydroxy-3,4-dihydroaucubigenin, des-p-hydroxybenzoyl kisasagenol364

B, ajugol, verminoside and 6-transcaffeoyl ajugol. Further phytochemical investigation of the365

fruits of Kigelia africana yielded a new phenylpropanoid derivative identified as 6-p-366

coumaroylsucrose together with ten known phenylpropanoid and phenylethanoid derivatives and367

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a flavonoid glycoside [37]. A biologically monitored fractionation of the fruit led to the isolation368

and identification of the naphthoquinones, kigelinone, isopinnatal, dehydro-alpha lapachol and369

the phenylpropanoids p-coumaric acid and ferulic acid.370

371

4.2 Chemical constituents of Kigelia africana stem372

A study of the antimicrobial properties of the aqueous stem bark extract of Kigelia africana373

revealed the presence of two naphthoquinones kigelinone and isopinnatal [35,3].Three known374

iridoids: specioside, verminoside and minecoside have also been isolated from the stem bark375

[40]. The dichloromethane extract of the stem bark contain naphthoquinones which possess anti376

trypanosomal properties [3,4] while kigelin, β-sitosterol, 1,3-dimethylkigelin and ferulic acid377

have been isolated from the bark, while the isolation of kigeliol from the wood and balaphonin378

from the stem bark have been reported [38, 39].379

380

4.3 Chemical constituents of Kigelia africana root381

Earlier workers [40] reported the isolation and identification of the naphthoquinones, kigelinone,382

isopinnatal, dehydro-alpha-lapachol and the phenylpropanoids p-coumaric acid and ferulic acid383

from the root of Kigelia africana. Steroids, iridoids and coumarins have been isolated from the384

root bark [38] as well as three isocoumarins: 6-methoxymellein, kigelin and 6-demethylkigelin385

[41]. The isolation of kiglin and 6-methoxymellein together with two known compounds,386

stigmasterol and lapachol from the root has also been reported [43]. Naphthoquinones that387

possess anti-trypanosomal properties have been reported in the dichloromethane extract of the388

root [3,4] while two non-quinonoid aldehydes, norviburtinal and pinnatal have been obtained389

from the root bark [4, 43].390

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391

4.4 Chemical constituents of Kigelia africana leaf392

The hexane extract of the leaf of Kigelia africana has been reported to be rich in hydrocarbons393

and some volatile compounds. In a study that qualitatively and quantitatively analyzed the394

hexane extract for various chemical compositions, it was revealed to contain twelve compounds395

with the major ones identified as n-hentriacontane, 1-tricosene, 11-(2,2-396

dimethylpropylheneicosane, 2,6,10-trimethyldodecane, pentafluoroheptadecyl ester, 2-397

ethylhexyloctadecyl sulfurous acid ester, heneicosane and hexyloctylsulfurous acid ester. Others398

are 4,4-dimethylundecane, methyl-12-methyltetradecanoate, 1-iodohexadecane and 1-399

iododecane. Hentriacontane have been reported to have a possible anti-tumour activity while400

methyl-12-methyltetradecanoate has also been reported for its inhibition capacity on the401

development of coneal angiogenesis, which is responsible for blindness and other infections [35].402

Flavonoids and iridoids [36] and a 7-O-glucoside [42-44] have also been found in the leaves403

(Table 2). The structural formulae of some of the chemical constituents isolated from Kigelia404

africana are presented in Figure 1.405

406

5.0 Conclusion407

As a medicinal plant with a large array of secondary metabolites, Kigelia africana is applied in408

traditional medicine to treat a wide range of diseases. There is the need to scientifically verify the409

various healing attributes ascribed to it, following which establishment of the exact identity of410

the chemical constituent responsible for any confirmed biological activity would enrich the411

available chemical lead for new drugs.412

413

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414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

References435

436

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[1] Mann A, Gbate M. and Umar AN.Medicinal and Economic Plants of Nupeland, Jube-437Evans Books & Publications, Bida. 1st Edition. .2003; 277 pp438

439440

[2] Otimenyin SO. Uzochukwu DC. Spasmolytic and Anti-diarrhea effects of the bark of441Erythrina senegalensis and root of Kigelia africana, Asian J Pharm Clin Res 2012; 3 (4):44211-14443

444[3] Saini S, Kaur H,Verma,B.,Ripudaman, Singh S. Kigelia africana (Lam.) Benth. An445

overview. Nat Prod Rad 2009; 8 (2): 190-97.446447

[4] Olatunji AG. Atolani O. Comprehensive scientific demystification of Kigelia africana:a448review. Afr J Pure Appl Chem 2009; 3(9): 158-64.449

450451

[5] Oyelami OA. Yusuf KO. Oyelami AO. The use of Kigelia africana in the management of452polycystic ovary syndrome (PCOS). Chin Med 2012; 3, 1-3.453

454(6) Oyeku A. Oyelami, Kafayat O. Yusuf, Atinuke O. Oyelami. The Use of Kigelia455africana in the Management of Polycystic Ovary Syndrome (PCOS) Chin Med 2012;4563:1-3457

458(7) Bharti N, Singh S. Fermida N, Amir A. Isolation and in vitro antiamoebic activity of459

iridoids isolated from Kigelia pinnata, ARKIVOC 2006: 69-76460461

(8) Binutu OA. Adesogan KE. Okogun,JI. Antibacterial and antifungal compounds from462Kigelia pinnata, Planta Med 1996; 62 (4): 352-353.463

464(9) Owolabi OJ,Omogbai EKI. Obasuyi, O. Antifungal and antibacterial activities of the465

ethanolic and aqueous extracts of Kigelia africana (Bignoniaceae) stem bark. Afri J466Biotechnol 2007; 6 (15):1677-80.467

468469

(10) Tyagi A, Singh V. Bharadwaj M, Kumar A, Thakur K. Isolation and antibacterial470susceptibility testing of multi drug resistant Pseudomonas aeruginosa causing urinary471tract infection. J Chem Pharm Res 2011; 3(4): 342-347.472

473474

(11) Chivandi, E, Cave, E, Davidson, BC, Eriwanger, KH, Mayo, D and Madziva, MT.475Suppression of Caco-2 and HEK-293 cell proliferation by Kigelia africana, Mimusops476zeyheri and Ximenia caffra seed oils. In vivo 2012; Jan-Feb, 26 (1): 99-105. PubMed.477

478(12) Picerno P, Autore,G.,Marzocco,S.,Meloni,M..Sanogo R Aquino RP. Anti-479

inflammatory activity of verminoside from Kigelia africana and evaluation of480cutaneous irritation in cell cultures and reconstituted human epidermis. J Nat Prod4812005; 68:1610-16.482

UNDER PEER REVIEW

21

483(13) Owolabi OJ. Omogbai EKI. Analgesic and anti-inflammatory activities of the484

ethanolic stem bark extract of Kigelia africana (Bignoniaceae), Afri J Biotechnol4852007; 6 (5): 582-85.486

487(14) Hemamalini. K Suvidha. S, Anurag Bhargav2 And Uma Vasireddy488

Evaluation Of Anti-Ulcer Activity Of Methanolic Extracts Of Kigelia Africana,489Sophora Interrupta And Holoptelea Integrifolia Leaves In Experimental Rats. Int J490Curr Pharm Res, Vol 4, Issue 4, 61-66491

492[15]. K. Hemamalini , Anurag Bhargav, Uma Vasireddy, S. Suvidha, V. Ramya493Krishna G. L. Soujanya. Phytochemical And Anti-Cholinesterase Of Leaves Of494Different Herbs On Frog’s Experimental Models International Journal Of Biological495& Pharmaceutical Research. 2012; 3(3): 373-376.496

497[16]. Atawodi SE. Evaluation of the hypoglycemic, hypolipidemic and antioxidant effects of498methanolic extract of “Ata-ofa” polyherbal tea (A-Polyherbal) in alloxan-induced diabetic rats.499Drug Inv Today 2011; 3(11): 270-76500

501[17] Atawodi SE, Atawodi JC. Azadirachta indica (neem): A plant of multiple biological and502

pharmacological Activities. Phytochem Rev 2009; 8(3): 601–20503504505

[18] Gupta, R, Mathur, M, Bajai, VK. Katarachiya, P. Yadav, S. Kamal, R. Gupta, RS.506Evaluation of antidiabetic and antioxidant activity of Molinga oleifera in experimental507diabetes. J Diabetes, 2012; 4 (2): 164-171508

509[19] Gidado A, Ameh D.A. Atawodi, S.E and Ibrahim S. Antidiabetic Effect of Nauclea510

latifolia Leaf Ethanolic Extract in Streptozotocin-induced Diabetic Rats. Pharmacogn Res5112009;1(6): 392-95512

513[20] Okine LKN. Nyarko AK, Osei-Kwabena N, Oppong IV,Barnes,F. Ofosuhene,M. The514

antidiabetic activity of the herbal preparation ADD-199 in mice: a comparative study with515two oral hypoglycaemic drugs. J Ethnopharmacol 2004; 97 (1): 31-8.516

517[21] Nyarko AK. Okine LKN.Wedzi RK. Addo PA, Ofosuhene M. Sub-chronic toxicity518

studies of the antidiabetic herbal preparation ADD-199 in the rat: absence of organ519toxicity and modulation of cytochrome p450. J Ethnopharmacol 2005; 97(2): 319-25520

521[22] Olaleye MT. Rocha JB. Commonly used medicinal plants exhibit distinct in-vitro522

antioxidant activities against hepatotoxins in rat liver. Expl Toxicol Path 2007; 58 (6):523433-8.524

525526

.527528

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22

[23] Anvesh H, Vimal KV, Shailaja R . Antiulcer Effect of The Methanolic Extract of Kigelia529Africana.Lam, Benth (Bignoniaceae). Pharmacologyonline 2010; 1: 344-51530

531[24] Sharma US, Singh A. Agarwal V. Diuretic activity of Kigelia pinnata bark extract. J532

Pharmacol Res 2010; 1 (2): 17-20533534

[25] Ashraf, M. Ayub, M. Sajjad, T. Elahi, N. Ali, I. Ahmed, Z. Replacement of rotenone by535locally grown herbal extracts. Int J Agr Biol 2010; 12:77-80536

537[26] Azu OO, Duru FIO, Osinubi AA, Noronha CC, Elesha SO, Okanlawon AO. Protective538

agent, Kigelia africana fruit extract, against cisplatin-induced kidney injury in Sprague-539Dawley rats. Asian J Pharm Clin Res 2010; 3(2): 84-8.540

541

[27] Zofou D, Kengne AB, Tene M, Ngemenya MN, Tane P, Titanji VP. In vitro anti-542plasmodial activity and cytotoxicity of crude extracts and compounds from the stem bark543of Kigelia africana (Lam.) Benth (Bignoniaceae). Parasitol Res. 2011;108(6):1383-90544

545[28] Adoum, OA, Determination of toxicity effects of some savannah plants using brine546

shrimptest (BST) Int Jor P App. Scs 2008; 2(3): 1-5547548

549[29] Fafioye, OO. Plants with piscicidal activities in Southwestern Nigeria. Turk. J Fish Aquat550

sci. 2005; 5, 91-97.551552

[30] Hussain,H.,Krohn,K.,Ahmad,U.V.,Miana,G.A. and Green, I.R. Lapachol: an overview,553ARKIVOC 2007; 2:145-171.554

555[31] Jackson,S.J.,Houghton,P.J.,Retsas,S.,and Photiou, A Cytotoxicity of Norviburtinal and556

Isopinnatal from Kigelia pinnata against cancer cell lines, Planta Med 2000; 66: 758-761.557558

[32] Abioye AIR, Duru,FIO, Noronha CC. Okanlawon AO. Aqueous extract of the bark of559Kigelia africana reverses early testicular damage induced by methanol extract of Carica560papaya. Nig J Hlth Biomed Sci 2003; 2(2): 81-7561

562[33] Adeparusi EO, Dada,A.A. Alale OV. Effects of Medicinal Plant (Kigelia africana on563

Sperm Quality of African Catfish Clarias gariepinus (Burchell, 1822) Broodstock. J Agric564Sci 2010; 2(1): 193-99565

566[34] Dada AA, Adeparusi EO. Alale OV. Dietary dried Kigelia africana as fertility enhancer567

in female Clarias gariepinus (Burchell 1822). Agric Biol J North Am 2010; 1(5):791-95568569

[35] Atolani O, Olatunji AG. Epicuticular Wax and Volatiles of Kigelia pinnata Leaf Extract.570Ethnobotan Leafl 2010; 14: 797-06.571

572

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[36] GoudaYG, Abdel-baky AM., Darwish FM, Mohammed KM, Kasai R Yamasaki, K.573Iridoids from Kigelia pinnata DC. Fruits, Phytochem 2003; 63 (8) 887-92.574

575[37] GoudaYG, Abdel-baky AM, Mohammed KM, Darwish FM, Kasai R Yamasaki, K..576

Phenylpropanoid and phenylethanoid derivatives from Kigelia pinnata DC. Fruits, Nat577Prod Res 2006; 20(10): 935-939.578

579[38] Akunyili DN. Houghton PJ. Monoterpenoids and naphthoquinones from Kigelia pinnata580

bark, Phytochem 1993; 1015-1018.581582

[39] Akunyili DN, Houghton PJ. Raman A. Antimicrobial activities of the stem bark of583Kigelia pinnata J Ethnopharmacol 1991; 35(2), 173-177.584

585[40] Neelam B, Shailendra S, Fermida N, Amir A. Isolation and in vitro anti amoebic activity586

of iridoids isolated from Kigelia pinnata. General papers. ARKIVOC(x) 2006: 69-76587588

[41] Folashade O. Oyedeji, Olufunsho Samuel Bankole-Ojo589Quantitative evaluation of the antipsoriatic activity of sausage tree (Kigelia africana).590African Journal of Pure and Applied Chemistry Vol. 6(13), pp. 214-218, November 2012591

592[42] Moideen SVK, Houghton PJ, Rock P, Croft SL, Aboagye-Nyame F. Activity of extracts593

and naphthoquinones from Kigelia pinnata against Trypanosoma brucei brucei and594Trypanosoma brucei rhodesiense. Planta Med 1999; 65(6): 536-540.595

596[43] Houghton PJ, Photiou A, Uddin S, Shah P, Browning M, JacksonSJ. Retsas, S. Activity597

of extracts of Kigelia pinnata against melanoma and renal carcinoma cell lines. Plant Med5981994; 60 (5): 430-433.599

600601602603604605606607

.608

609

610

611

612

613

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614615616617

O

O

OOH

O

CH3

Kigelinone618619620621622623

HO

COOH

Coumaric acid624625626

O

OH

OHHO

OH OLuteolin627

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O

OH

OHHO

OH OLuteolin628

629630631

CH3

CH3O

O

OH

R

R'

OH

R=OH, R'=H PinnatalR=H, R'=OH Isopinnatal632

633634

O

O

O

CH3

OH

2-acetylnaphthao[2,3-b]furan-4,9-quinone635636637

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CH3

CH3

H3C

HH3C

HO

H

H

H3C

Stigmasterol638639640

CH3

CH3

H3C

HH3C

HO

H

H

H3C

CH3

Sitosterol641642643

CHOH3C

O

CH3

O

O

R

R

KigelinolIsokigelinol644

645646647

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648

COOH

OCH3

OH

COOH

OH

OH

O OH

CH3

H

O

O

O

O

Caffeic acid

Ferulic acid

2-(1-Hydroxyethyl)-2-acetylnaphtho-[2,3-b]-furan-4,9-dione

1,4 Benzoquinone649650651652653654

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O

O

CH3

CH3

OH

Lapachol655656657

O

CH3O

H3C

OH O

CH3

Kigelin658659660661

O

OHC

Norviburtinal662663664665666667668

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CCCOOHH

H

OCH3OH669

670Ferulic acid671

672673

O

C

HO

OHOH

OHOH

O674675

Quercetin676677678

Figure1: Structural formulae of some compounds found in Kigelia africana679680

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Table 1 Toxic effects of Kigelia africana extracts on different species of animalsS/N Animal Species Observed effect Plant part Extract Dose Route Reference:1 Artemia salina Moderate toxicity Root

FruitFruit

EthanolEthanolEthyl acetate

593µg/ml124µg/ml495µg/ml

Whole body Adoum,2008

2 Artemia salina Moderate cytotoxicity Fruit Ethanol 7500µg/ml Whole body Kolodziej,19973 Artemia salina Low toxicity Leaves Methanol 250µgml Whole body Ayuko et al,

20094 Fish Increased opercular

ventilation and tail finbeat leading toeventual fatique andeventual death

Bark Aqueous Oral/wholebody

Ufodike andOmoregie,1994

5 Sprague-Dawleyrats

Protective effectagainst cisplatin-induced kidneyoxidant injury

Fruit Methanol 500mg/kg100mg/kg

Oral Azu et al,2010

6 Wistar albinorats

No overt organspecific toxicity anddid not demonstrate apotential for druginteraction viacytochrome P450-mediated metabolism

Fruit Aqueous 100-500mg/kg Oral Nyarko et al,2005

7 Mice Reversed the effectsof severe hepaticnecrosis induced by alarge dose ofparacetamol

Leaves Aqueous 100mg/kg Oral Olaleye andRocha, 2008

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Table 2: Chemical Constituents of Kigelia Africana

S/No Compound Plant Part Bioactivity Reference

Kigelinone Stem bark Antibacterial,Antifungal

Akunyili and Houghton,1993;Akunyili et al,1991;Binutu etal, 1997

Isopinnatal Stem bark Antibacterial,antifungal, anti-malaria

Akunyili et al,1991; Weiss etal, 2000; Jackson et al, 2000,Binutu et al,1997

Kigelinol Stem bark Anti-malaria Weiss et al, 2000Isokigelinol Stem bark Anti-malaria Moideen et al,1999; Jackson et

al, 2000Lapachol Anti-cancer Binutu et al, 1997;Hussain et al,

2007Dehydro-alpha-lapachone Binutu et al,19972-(1-hydroxyethyl)naphtha[2,3-b]furan-4,9-quinineKigeliolBalaphoninΒ-SitosterolCaffeic acid

Stem bark

WoodStem barkBarkBark

Anti-trypanosoma

Cytotoxicity

Moideen et al, 1999

Houghton,2007Houghton,2007Desai et al,1971;Khan,1998Grace et al, 2002

Specioside Stem bark Antibacterial,Antifungal

Neelam et al, 2006

Verminoside Stem bark Neelam et al, 2006; Gouda etal, 2003; Picerno et al, 2005

MinecosideCarbohydrates, alkaloids, tannins, saponinsand glycosides

Stem barkBark

Neelam et al, 2006Owolabi and Omogbai, 2007

7-Hydroxyviteoid II Fruit Gouda et al, 2003

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7-Hydroxyeucommic acid Fruit Gouda et al, 20037-Hydroxy-10-deoxyeucomiol Fruit10-Deoxyeucommiol Fruit Gouda et al, 2003Jiofuran Fruit Gouda et al, 2003Jioglutolide Fruit Gouda et al, 20031-Dehydroxy-3,4-dihydroxy-3,4-dihydroaucubigenin

Fruit Gouda et al, 2003

des-p-hydroxybenzoyl kisasagenol B Fruit Gouda et al, 2003Ajugol Fruit Gouda et al, 20036-trans caffeoyl ajugol6-p-Coumaroyl sucroseβ-SitosterolQuercetinLuteolin3-(2'-hydroxyethyl)-5-(2''-hydroxypropyl)Dihydrofuran-2-(3H)one

FruitFruitFruitFruitFruitFruit

Gouda et al, 2003Gouda et al,2006Desai et al,1971;Khan,1998Grace and Davis,2002Grace and Davis,2002Gouda et al,2003

Isocoumarins6-Methoxymellein Root Govindachari et al,1971Kigelin Root6-Demethylkigelin Root3-Dimethylkigelin Root

Phenylpropanoidsp-Coumaric acid Root bark Antibacteria,

AntifungalBinutu et al, 1997; Grace et al,2002

Ferulic acid Root bark Binutu et al, 1997; Grace etal,2002

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Stigmasterol Root Govindachari et al, 1971

Non-quinonoid aldehydesNorviburtinal Root bark Joshi et al, 1982Pinnatal Root bark Joshi et al, 1982

Hydrocarbonsn-Hentriacontane Leaf Antitumour Atolani and Olatunji, 20101-Tricosene Leaf ,,11-(2,2-Dimethylpropyl)heneicosane Leaf ,,2,6,10-Trimethyldodecane Leaf ,,Heneicosane Leaf ,,4,4-Dimethylundecane Leaf ,,

,,

Pentafluoroheptadecyl ester Leaf ,,2-ethylhexyloctadecyl sulphurous acid ester Leaf ,,Hexyloctyl sulphurous acid ester Leaf ,,Methyl-12-methyltetradecanoate Leaf Inhibition of corneal

angiogenesisAtolani and Olatunji, 2010;Grace et al, 2002

1-Iododecane Leaf Atolani and Olatunji, 201011-Iodohexadecane Leaf ,,

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