PHYTOCHEMICAL SCREENING AND ANTICONVULSANT STUDIES OF ETHYL ACETATE FRACTION OF ETHANOLIC EXTRACT OF THE LEAVES OF GLOBIMETULA BRAUNII (LORANTHACEAE) PARASITING ON PILIOSTIGMA THONINGII (FABACEAE)
PHYTOCHEMICAL SCREENING AND ANTICONVULSANT STUDIES OF ETHYL ACETATE FRACTION OF ETHANOLIC EXTRACT OF THE LEAVES OF GLOBIMETULA BRAUNII (LORANTHACEAE) PARASITING ON PILIOSTIGMA THONINGII (FABACEAE)
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Date
2013-03
Authors
MUHAMMAD, Kamal Ja'afar
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Abstract
The ethyl acetate soluble fraction of ethanol extract of leaves of Globimetula braunii, a plant
used in ethnomedicine for the treatment of epilepsy and diabetes among other ailments, was
subjected to phytochemical and anticonvulsant screening. The phytochemical techniques
employed were dry column vacuum chromatography and preparative thin layer chromatography.
The anticonvulsant activity was studied using maximal electroshock test, pentylenetetrazole and
4-aminopyridine-induced seizures. The result of preliminary phytochemical screening carried out
on the crude ethanol extract revealed the presence of saponins, carbohydrates, flavonoids,
tannins, anthraquinones and steroids. Similarly, tannins, flavonoids and steroids/terpenes were
found to be present in the ethyl acetate fraction. Extensive chromatographic separation of the
ethyl acetate soluble fraction using silica gel, dry column vacuum chromatography, followed by
crystallization led to the isolation of 3, 12-bis [2-(4-hydroxyphenyl) ethyl]-5, 7, 14, 16-
tetrahydroxy-2, 11-dioxacyclooctadecane-1, 10-dione. The structure of this compound was
established by spectral analysis including 1D and 2D NMR. In the pharmacological screening,
150 mg/kg of the fraction protected 83.33% of test animals against pentylenetetrazole-induced
seizure in mice whereas sodium valproate a standard anti-epileptic drug offered 100% protection.
In the 4-aminopyridine-induced seizure model, the fraction produced an increase in the mean
onset of seizure in unprotected animals. The fraction did not exhibit a significant activity against
maximal electroshock convulsion. The median lethal dose of the fraction was found to be
1261.91 mg/kg. These results suggest that the ethyl acetate fraction of Globimetula braunii
Leaves extract possesses psychoactive compound that may be useful in the management of petit
mal epilepsy.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE AWARD OF A MASTERS
DEGREE IN PHARMACEUTICAL CHEMISTRY
DEPARTMENT OF PHARMACEUTICAL AND MEDICINAL
CHEMISTRY,
FACULTY OF PHARMACEUTICAL SCIENCES,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
PHYTOCHEMICAL SCREENING,, ANTICONVULSANT STUDIES,, ETHYL ACETATE FRACTION,, ETHANOLIC EXTRACT,, LEAVES,, GLOBIMETULA BRAUNII,, (LORANTHACEAE),, PARASITING,, PILIOSTIGMA THONINGII,, (FABACEAE).