KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES OF OCIMUM

International Journal of Pharmaceutical Applications ISSN 0976-2639. Vol 3, Issue 1, 2012, pp 267-270 http://www.bipublication.com

KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES OF OCIMUM SANCTUM LINN (TULSI)

D. J. Garkal, S. V. Taralkar*, Prasanna Kulkarni,

Sujitkumar Jagtap, and Archana Nagawade Chemical Engineering Department, MAEER’s Maharashtra Academy of Engineering,

Alandi (D), Pune-412105. Maharashtra. India. *Corresponding Author: [email protected]

Phone no: +912030253500, Fax: +912030253799. Mobile: +919011332500 ABSTRACT:

Herbs are well known for their medicinal values and they are used for the same purpose since many years. Ocimum Sanctum Linn (Tulsi) is one of the common herbs for its various medicinal applications. Eugenol is the important ingredients found in tulsi. In this work, efforts have been made to extract eugenol by solvent extraction from tulsi leaves. The extracted samples were analysed with GC for determination of eugenol content. Kinetic model has been used to analyze the experimental data.

Keywords: Eugenol, Ocimum Sanctum Linn, Kinetic Model.

[I] INTRODUCTION Herb is a plant that is valued for flavour, scent, medicinal or other qualities. Herbs are used in cooking, as medicines, and for spiritual purposes. Herbs have a variety of uses including culinary, medicinal, or in some cases even spiritual usage. General usage differs between culinary herbs and medicinal herbs [1]. Among the plants known for medicinal value, the plants of genus Ocimum belonging to family Labiatae are very important for their therapeutic potentials. Ocimum sanctum L. (Tulsi), Ocimum gratissium (Ram Tulsi), Ocimum canum (Dulal Tulsi), Ocimum basilicum (Ban Tulsi), Ocimum kilimandscharicum, Ocimum ammericanum, Ocimum camphora and Ocimum micranthum are examples of known important species of genus Ocimum which grow in different parts of the world and are known to have medicinal properties. Ocimum sanctum L., known as ‘Tulsi’ in Hindi and ‘Holy Basil’ in English, is an erect softy hairy aromatic herb or under shrub found throughout India. Tulsi is commonly cultivated in gardens [2].

Leaves of tulsi contain number of active ingredients having very good medicinal value[3,4,5]. Eugenol is an allyl chain-substituted guaiacol [3]. Eugenol is a member of the phenylpropanoids class of chemical compounds. It is a clear to pale yellow oily liquid extracted from certain essential oils especially from Holy basil (Tulsi) and bay leaf, clove oil, nutmeg, cinnamon etc. It is slightly soluble in water and soluble in organic solvents. It has a spicy, clove-like aroma [6]. Eugenol is used in perfumeries, flavorings, essential oils and in medicine as a local antiseptic and anesthetic [7]. It is a key ingredient in Indonesian kretek (clove) cigarettes. It was used in the production of iso-eugenol for the manufacture of vanillin, though most vanillin is now produced from phenol or from lignin. When mixed with zinc oxide, eugenol forms a material which has restorative and prosthodontic applications in dentistry. Eugenol derivatives or methoxyphenol derivatives in wider classification are used in perfumery and flavoring [8]. They are used in formulating insect attractants and UV absorbers, analgesics, biocides, and antiseptics. Several

KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES

S. V. Taralkar, et al. 268

other pharmacological effects, such as antitumor, hepatoprotective, anti-inflammatory (oral & topical), anti-ulcer, antimicrobial, anti-hyperlipidemic, and anti-viral activities, have also been attributed [9]. They are also used in manufacturing stabilizers and antioxidants for plastics and rubbers [10]. It is also used in mouse traps.

[II] MATERIALS AND METHODS 2.1. Materials

Leaves of Ocimum Sanctum Linn. (Tulsi) collected from near by area of Alandi, Pune, Maharashtra, methanol (AR grade) was used as solvent. 2.2. Batch Extraction setup The extraction of eugenol was carried out with batch extraction setup (Figure 1). It consists of a 500 ml reactor in which extraction is to be carried out; a turbine type four blade agitator connected with motor (REMI, maximum speed of 1200 rpm) was used.

Figure 1: Batch extraction setup

2.2. Analysis Extracted samples were analysed by gas chromatography technique (GC) with TCD as detector and capillary column of 25 m long. The oven, injector and detector temperatures were maintained at 2000 C. Nitrogen were used as carrier gas.

[III] MATHEMATICAL MODEL Kinetic Model: Many reserchers used various models to describe solid-liquid extraction process [11,12,13] Adamou Harouna-Oumarou et al. [12] shows, in the study of the mechanisms and kinetics in the extraction process of water soluble compounds from tilia sapwood, that a model based on a second-order extraction process was the most suitable model for a solid–liquid extraction process. It was then possible to build the kinetic models of a solid–liquid extraction and the extraction order and rate constant remained to be determined by experiments. According to a second-order rate law Rakotondramasy-Rabesiaka, et. al. [13] described the rate of dissolution for the solute contained in the solid from plant cells to solution by Eq. (6):

------------------- (6) Where k is the second-order extraction rate constant (L g−1 min−1), Cs the extraction capacity (concentration of solute at saturation in mg L−1) and Ct is the concentration of solute in the suspension at any time t (min). By considering the initial and boundary conditions, t=0 to t and Ct =0 to Ct, the integrated rate law for a second-order extraction was obtained:

-------------------- (7) By transforming Eq. (7), a linear form shown in Eq. (8) can be obtained and the extraction rat can be written as Eq. (9):

-------------------- (8)

------------- (9) The initial extraction rate, h, as Ct/t when t approaches 0, can be defined as: ----------------------- (10) and, the concentration of solute at any time can be expressed after rearrangement



as:

------------------ (11) The initial extraction rate, h, the extraction capacity, Cs, and the second-order extraction rate constant, k, can be determined experimentally from the slope and intercept by plotting t/Ct versus t. [III] RESULTS AND DISCUSSION 3.1. Batch Extraction Fresh leaves of Ocimum sanctum were washed under tap water and then kept 36 h for drying. After draying, those leaves were cut into small pieces. 10 g of small pieces were weighed. Those weighed pieces were then fed to the stirred type batch reactor with 150 ml methanol. The speed of agitation was kept at 500, 700 and 1000 rpm. The extracted samples at known interval of time was analysed with GC for eugenol content. The percentage of eugenol was calculated from the final concentration and the initial concentration present in leaves. Table 1 shows the percent extraction of eugenol from tulsi leaves at different agitation speed and room temperature. From Figure 2 and table 1, its is clear that as agitation speed increases the extraction of eugenol also increases this increase in extraction is mainly due to the external mass transfer coefficient. but the values are not that much higher. The difference is very small. Table 1: Extraction of eugenol at 500 rpm

Time (min.)

Agitation speed (rpm)

Percent Extraction (%)

30 500 74.48 60 500 75.74 90 500 76.56 30 700 73.77 60 700 76.67 90 700 77.94 30 1000 75.77 60 1000 78.49 90 1000 80.94

70

75

80

85

0 20 40 60 80 100

Extraction time (min)

Extra

ctio

n of

eug

enol

(%)

500 rpm700 rpm1000 rpm

Figure 2: Effect of agitation speed on extraction of eugenol

3.2 Kinetic Model Second order kinetic model was used to describe the solid liquid extraction process of eugenol from tulsi. The model was solved and programmed with Polymath software. Figure 3, 4, 5 shows that the comparison of experimental and model values of concentration of eugenol at 500, 700 and 1000 rpm agitation speed. The model values matches with experimental values with very less difference and can be neglected in all experiments.

Figure 3: Comparison between experimental and model values of eugenol concentration at 500 rpm agitation speed





[III] CONCLUSIONS

Extraction of eugenol from leaves of Ocimum Sanctum Linn (Tulsi) was done with methanol as solvent. Agitation speed not influencing much on extraction capacity of eugenol. The kinetic model used fits very well with experimental data. ACKNOLEDGEMENTS The authors are thankful to AICTE for providing financial assistance in terms of MODROD project. Authors are also thankful to management of MAE, Alandi for providing the research facilities to carry out this work.

REFERENCES [1] K R, Kirtikar, B D Basu, “Ocimum sanctum in

Indian Medicinal Plants” (Published by LB Basu, Allahabad), 1965.

[2] Cambridge Advanced Learner’s Dictionary, Cambridge University Press, headword “herb”.

[3] S. Anandjiwala, J. Kalola, M. Rajani, “Quantification of eugenol, luteolin, ursolic acid, and oleanolic acid in black (Krishna Tulasi) and green (Sri Tulasi) varieties of ocimum sanctum linn using high-performance thin layer chromatography”, J AOAC Int, 89 (6), 1467-1474, 2006.

[4] J.F. Carris, and K.S.Bhaskar, (1955), (Periodical Experts Book Agency)Vol 3.

[5] P. D Nadig, S. Laxmi, “Study of anti-tussive activity of ocimum sanctum linn in guinea pigs”, Indian J. Physiol Pharmacol, 49 (2), 243-245, 2005.

[6] P. Prakash, N. Gupta, “Theruptic uses of Ocimum Sanctum Linn.(Tulsi) with a note on eugenol and its pharmaceutical actions: A short review”, Indian journal of Physiol Pharmacol, pg.125-131, 2005.

[7] B.K. Jadhav, K.R Khaandelwal, A.R Ketakr, S.S. Pisal, “Formulation and evaluation of mucoadhesive tablets containing eugenol for treatment of periodontal diseases”, Drug dev. Ind. Pharma 30, pg. 195-203, 2004.

[8] A. Bennett, I. F. Stamford, I.A. Tavares, S. Jacobs, F. Capasso, N. Macolo, G. Autore, V. Romono “ The biological activity of Eugenol, a major constituent of nutoncy ; studies on protsaglandins, the intestine and other tissus.” Phytotherapy Research, 2, pg. 124-130, 1998.

[9] D.A. Right, J.P. Payne, “A clinical study of intravenous anaesthesia with a eugenol derivative”, British Journal of Anasthesia 34, pg. 379-385, 1962.

[10] Eugenol oil overdose, New York Times Health Guide.

[11] S. V. Taralkar, D.J. Garkal, “Solid-liquid extraction process of active ingredients from medicinal plants–mathematical models”, International Journal chemical sciences and applications, vol. 1, pg. 82-85, 2010.

[12] H. Adamou, Harouna- Ocmarou, H. Fauduet, Cambridge Porte, “Kinetic and model building of leaching of water soluble compounds of Tilia Sapwood”, Separation and Purification Technology 45, pg. 169-173, 2005.

[13] L. Rakotondramasy-Rabesiak, J. Havet, C. Porte, H. Fauduet, “Solid-liquid extraction of protopine from Fumaria officinalis L.-experimental study and process optimization”, Sep. and Puri. Tech. 59, 253-261, 2008.

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KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES OF OCIMUM