Synthesis, characterisations, lipid lowering activity and antibacterial activities of some Benzoyl ester substituted Embelin derivatives

Article abstract of DOI:10.13005/ojc/330150

The research article represents the extraction of Embelin from its plant source and synthesis, characterisation, lipid lowering activities and antibacterial studies of some Benzoyl ester substituted derivatives of Embelin. The derivatives of Embelin, EL

Full text of DOI:10.13005/ojc/330150

ISSN: 0970-020 X
CODEN: OJCHEG
2017, Vol. 33, No. (1):
Pg. 430-438
ORIENTAL JOURNAL OF CHEMISTRY
An International Open Free Access, Peer Reviewed Research Journal
www.orientjchem.org
Synthesis, Characterisations, Lipid Lowering Activity and
Antibacterial Activities of Some Benzoyl Ester Substituted
Embelin Derivatives
ASHOK N. PATANGE
Department of Chemistry, Bhavan’s College, Munshi Nagar, Andheri (West),
University of Mumbai, Mumbai 400001, Maharashtra 400058, India.
*Coresponding author E-mail: ashokpatange78@gmail.com
http://dx.doi.org/10.13005/ojc/330150
(Received: December 06, 2016; Accepted: January 26, 2017)
ABSTRACT
The research article represents the extraction of Embelin from its plant source and synthesis,
characterisation, lipid lowering activities and antibacterial studies of some Benzoyl ester substituted
derivatives of Embelin. The derivatives of Embelin, EL-1 to EL-5 were prepared by treating Embelin
with Meta and Para substituted benzoyl chloride in presence of base pyridine and dichloromethane.
Benzoyl ester substituted derivatives of Embelin molecule also shows more or less medicinal
properties then the parent Embelin molecule. The synthesized compound were characterised and
identified on the basis of elemental analysis, UV, FTIR, Mass and NMR spectroscopy and their
antibacterial activities were studied against test organism viz B.subtilis gram positive, S.aureus Gram
positive, C.Albicans Antifungal and E.coli Gram negative. The lipid lowering activities of prepared
compound were also studied in percentage on pancreatic lipase inhibition simply on the basis of
change in international unit (IU).
Keywords: Embeliaribes, IC50 value, B.subtilis Gram positive,
S.aureus Gram positive, C.albicans antifungal and E.coli Gram negative.
INTRODUCTION
traditional Indian medicine Embelia ribes is used
as medicinal plant for the treatment of various
ailments. Embelin (3-undecyl 2, 5- dihydroxy
,1,4 –benzoquinone) was an important naturally
occurring alkyl substituted hydroxyl benzoquinone
product and one of the main constituent of embelia
ribes burm ,fruits of the plants contain a quinine
derivative embelinan alkaloid chiristembine4and
volatile oil vilangin ,its chemical constituent is 2,5-
It has been long recognised that natural
products acts as a lead structures for various
drug discovery1-2 because of their high chemical
diversity, biochemical specificity and other molecular
properties that make them favourable as a drug
which serve to differentiate them from libraries
of synthetic and combinatorial compounds3.Inthe

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PATANGE, Orient. J. Chem., Vol. 33(1), 430-438 (2017)
dihydroxy -4-undecyl- 3,6 –benzoquinone5. The
variety of biological activities of this compounds have
been studied and evaluated for anti spermatogenic
effect 6 and urinary tract infection7.Literature review
shows that the phytochemical and pharmacological
properties of embeliaribes as a medicinal plant had
studied. Embelin has antibacterial and antiprotozoal
properties and due to its cooling effects it is widely
used in skin related ailments . It also improves the
brain functioning and strengthens the nervous system.
It is normalises the digestive activities. It helps in
purifying the blood and also helpful in urine related
problems.Benzoylester substituted derivatives of
Embelin molecule also have the medicinal properties ii)
more or less then the parent Embelin molecule.In the
present study we were prepared some Benzoyl ester
substituted derivatives of Embelin. The synthesized
compound were characterised and identified on the
basis of elemental analysis, UV, FTIR, Mass and
NMR spectroscopy and their antibacterial activities
were studied against test organism viz B. subtilis
gram positive, S.Aureus gram positive, C.Albicans
Antifungal and E.Coli gram negative. The lipid
lowering activities of prepared compounds were also
studied in percentage [change in international unit
(IU)] on pancreatic lipase inhibition.
(0.003401 moles ,1 eq.) and 1.61g of pyridine
(0.02041 moles,6 eq.) in 30ml of Dichloro
methane.The reaction mixture was stirred at
room temperature for next 5 min. when clear
solution of reaction mixture was obtained.The
reaction mixture was kept in cooling bath (15-
180C) and to that 2.7 g (2.7ml) of 4-tert.butyl
benzoyl chloride (0.01306 moles,4.0 eq.) was
added drop wise through dropping funnel over
a period of 10 minutes. The reaction mixture
was stirred at room temperature for next 24
hours.The reaction mixture was monitored by
TLC for the completions of reaction.
Synthesis of 2,5-di-O-(4-methyl phenyl
carbonyl)-3-undecyl-1,4-benzoquinone (EL-2)
in a three neck 100ml round bottom flask fitted
with magnetic stirrer ,guard tube ,cooling bath
was charged a mixture of 1.0g of embelin
(0.003401 moles ,1 eq.) and 1.61g of pyridine
(0.02041 moles,6 eq.) in 30ml of Dichloro
methane.The reaction mixture was stirred at
room temperature for next 5 min. when clear
solution of reaction mixture was obtained.The
reaction mixture was kept in cooling bath (15-
18 0C) and to that 2.1 g (1.75ml) of 4-methyl
benzoyl chloride (0.01306 moles,4.0 eq.) was
added drop wise through dropping funnel over
a period of 10 minutes. The reaction mixture
was stirred at room temperature for next 24
hours.The reaction mixture was monitored by
TLC for the completions of reaction.
Synthesis of 2,5-di-O-(3-bromo phenyl
carbonyl)-3-undecyl-1,4-benzoquinone (EL-3)
in a three neck 100ml round bottom flask fitted
with magnetic stirrer ,guard tube ,cooling bath
was charged a mixture of 1.0g of embelin
(0.003401 moles ,1 eq.) and 1.61g of pyridine
(0.02041 moles,6 eq.) in 30ml of Dichloro
methane.The reaction mixture was stirred at
room temperature for next 5 min. when clear
solution of reaction mixture was obtained.The
reaction mixture was kept in cooling bath (15-
18 0C) and to that 3.0 g (1.76ml) of 3-bromo
benzoyl chloride (0.01306 moles,4.0 eq.) was
added drop wise through dropping funnel over
a period of 10 minutes. The reaction mixture
was stirred at room temperature for next 24
hours.The reaction mixture was monitored by
TLC for the completions of reaction. Similarly
the compound, 2,5-di-O-(3-chloro phenyl
MATERIAL AND METHODS
All chemicals used were of A.R Grade and
purchased from S.D Fine and Lobachem chemicals
(Mumbai) and were used further purification. The iii)
experimental part divided in to two parts
Isolation of Embelin
The parent molecule embelin (3-undecyl
2,5- dihydroxy ,1,4 –benzoquinone) was extracted
and isolated from the fine powered berries of embelia
ribes by the method explained by Gagan V.D &
et al8-9. The isolated Embelin further purified and
used for the synthesis of Benzoyl ester substituted
derivatives of Embelin.
Preparation of Benzoyl ester substituted
derivatives of Embelin (EL-1 -EL-5)
i)
Synthesis of 2,5-di-O-(4-tert.butylphenyl
carbonyl)-3-undecyl-1,4-benzoquinone (EL-1)
in a three neck 100ml round bottom flask fitted
with magnetic stirrer ,guard tube, cooling bath
was charged a mixture of 1.0g of embelin

PATANGE, Orient. J. Chem., Vol. 33(1), 430-438 (2017)
432
carbonyl)-3-undecyl-1,4-benzoquinone
(EL-4) also prepared by the above method.
Synthesis of 2,5-di-O- phenyl carbonyl-3-
undecyl-1,4-benzoquinone (EL-5) in a three
neck 100ml round bottom flask fitted with
magnetic stirrer ,guard tube, cooling bath
was charged a mixture of 1.0g of embelin
(0.003401 moles ,1 eq. ) and 1.61g of
pyridine (0.02041 moles,6 eq.) in 30ml of
Dichloro methane. The reaction mixture
was stirred at room temperature for next
5 minutes. when clear solution of reaction
mixture was obtained. The reaction mixture
Hitachi Perkin Elmer spectrophotometerin CDCl3
Using TMS as internal standard. FTIR spectra (in
4000–450 cm–1range) of Embelin and its derivate
were recorded in KBr pellets (2 mg / 200 mg KBr)
using a FTIR Perkin Elmer 1750 in department of
chemistry, University of Mumbai, Mumbai., the mass
spectra were recorded onTOF-MS-ES[Micromass:Q-
TOF micro(YA-105)] mass spectrophotometer.
iv)
1H NMR of compound ( EL-1) (300 MHz, CDCl3
dppm
1H NMR (300 MHz, CDCl3) dppm: 0.86
(t,3H,J=7.0 Hz),1.0-1.6 (m,36H),2.5(t,2H, J=7.5
Hz),6.75(S,1H),7.4-8.2 (m,8H).
0
was kept in cooling bath (15-18 C) and
to that 1.91 g (1.6ml) of benzoyl chloride
(0.01306 moles,4.0 eq.) was added drop wise
through dropping funnel over a period of 10
minutes. The reaction mixture was stirred
at room temperature for next 24 hours. The
reaction mixture was monitored by TLC for
the completions of reaction.
1
In the H NMR spectra of compound
(EL-1) a peak for side chain terminal methyl as
triplet appears at d 0.87 (J=7.5 Hz),the complex
unsymmetrical multiplate in the region between
d1.0-1.6 integrating for 36 protons were assign to
two tertiary butyl and side chain methylene group
(9 x –CH2) protons. The triplet at d 2.5 (J=7.5 Hz)
integrating for was assign to allylic methylene group.
The singlet for aromatic ring proton appears at d 6.75
and three sets of doublet resonating around d 7.55,
d 7.55 and d 8.09 corresponds to 2H, 2H and 4H.
RESULT AND DISCUSSIONS
1
The H NMR spectra were recorded on
R
O
Cl
O
OH
O
+
→
R
O
-(CH2)10 -CH3
O
HO
-(CH2)10 -CH3
O
O
O
R
Embelin (EL)
Cl
O
Cl
CH3
O
Where R =
,H
Schme 1: Synthesis of 2,5-di-O-(4-.substituited phenyl carbonyl)
-3-undecyl-1, 4-benzoquinone(EL-1,EL-2& EL-5)
O
O
O
Cl
O
O
X
OH
→
O
-(CH2)10 -CH3
O
+
HO
-(CH2)10 -CH3
X
O
O
Embelin(EL)Where X =
Br , Cl
X
Schme 2: Synthesis of 2,5-di-O-(3-.halophenyl carbonyl)
-3-undecyl-1, 4-benzoquinone(EL-3 & EL-4)

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Lipid lowering activity and Antibacterial prepared in 0.2M phosphate buffer,pH-8.0.this
activities
samples was used as test sample for all further
The synthetic derivatives of Embelin were assays.
subjected to lipid lowering activity to get a more
potent drug candidate in this domain. compounds Assays for lipase inhibitory activity: Lipase
(EL-1 –EL-5)10-11 were dissolved in 1ml DMSO to assay
obtain a 10mm stock solution and were vortexes
lipase assay was performed by method
to dissolution and stored at 4oC.the samples were described by Winkler and Stukmann, 1979 with
NMR ,FTIR and Mass Spectrum of Compound (EL-1) :
Fig.1: NMR spectra of El-1
Fig.2: Mass spectra of El-1
Fig.3: FTIR spectra of El-1

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PATANGE, Orient. J. Chem., Vol. 33(1), 430-438 (2017)
modification 12assays was designed using a 96-well ìM) of analogue at the conc., where the % inhibition
format.The substrate used in this assay was p-nitro of lipase was measured as 50% in two near straight
phenol plamitate (Sigma cat.no. N-2752) 4.5 mg points .the value of IC50 was derived from linear
p-nitro phenol palmitate was dissolved in 200ml regression.The value derived based on interpolated
of DMF and volume made up to 10ml with 0.1M data.The IC50 values of synthesized compounds (EL-
phosphate buffer at a conc. Of 5 mg/ml .the reaction 1 to EL-5) shows better pancreatic lipase inhibition in
mixture was incubated at 370C and optical density comparison with starting material embelin (Table-3)
was measured at405 nm after incubation .enzyme and can act as a lead in developing new drugs in
activity was presented in the form of international lipid altering domain.
unit (IU).
Antibacterial spectrum of Embelin and its
Lipase activity
One enzyme unit of lipase is defined as that
derivatives
Antibacterial activity of Embelin and its
quantity releasing 1nm of free phenol from substrate derivatives were tested against three bacterial strains
(p-nitro phenol plamitate) min-1/ml under the standard viz Escherichia coli (Gram-ve), staphylococcus
assay condition.
aureus(gram+ve),bacillus subistilis(Gram+ve) where
antifungal activity was tested against the yeast
candida albicans, stock solution of the compounds
Lipase inhibition assay
The conc. Of synthetic analogues checked were prepared at 10 mg/ml concentration in DMF.
were 100ìM and 200ìM. The assay was similar to Each compound was tested for its antibiotic activity
assay described above except 40ml of test sample at 250g concentration by agar diffusion method 13-15
was used instead of phosphate buffer in control. against the microorganism mentioned above. The
Optical density was measured at 0 hr and following antibacterial and antifungal activity of the embelin
incubation at 370C.
derivatives were determined and compared with that
of parent compound embelin(Table-3).While embelin
showed antibacterial activity against B.subtilis (Gram
Enzyme inhibition
Enzyme inhibition was presented in the + ve) and antifungal activity against C.albicans, the
term of relative activity and % inhibition simply on activity was completely knocked off in all compounds
the basis of change in international unit (IU).
indicates that the role of the –OH group at these
position in conferring the antibiotic activity.
IC50 calculation
IC50 of each compound was calculated
manually from dose dependent graph (6.25 mM -200
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