kinetic model for extraction of eugenol from leaves - BioIT ...

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)
ABSTRACT:
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: suyogkumartaralkar@yahoo.co.in
Phone no: +912030253500, Fax: +912030253799. Mobile: +919011332500
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 chainsubstituted
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 isoeugenol
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
other pharmacological effects, such as
antitumor, hepatoprotective, anti-inflammatory
(oral & topical), anti-ulcer, antimicrobial, antihyperlipidemic,
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.
[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 secondorder
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):
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 200 0 C. Nitrogen were used as
carrier gas.
(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
S. V. Taralkar, et al. 268

KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES
as:
85
------------------ (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)
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
Percent Extraction
(%)
E x tr a c t i o n o f e u g e n o l ( % )
80
75
70
0 20 40 60 80 100
Extraction time (min)
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
500 rpm
700 rpm
1000 rpm
S. V. Taralkar, et al. 269

KINETIC MODEL FOR EXTRACTION OF EUGENOL FROM LEAVES
Figure 4: Comparison between experimental and
model values of eugenol concentration at 700 rpm
agitation speed
Figure 5: Comparison between experimental and
model values of eugenol concentration at 1000
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.
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S. V. Taralkar, et al. 270