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).
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