Antinociceptive, anti-inflammatory and antipyretic effects of solanum incanum (linnaeus), craterostigma pumilum (Hochst) and euclea divinorum (Hiern) in animal models
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Date
2016-10
Authors
Mwonjoria, John Kingori
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Solanum incanum, Craterostigma pumilum and Euclea divinorum have been used
for generations as folklore medicine for various ailments associated with pain and
inflammation in humans in Kenya. However, there is scarcity of data on scientific
studies done on their effectiveness, modes of action, toxicity and their
phytochemical composition. The aims of this study was to evaluate the
antinociceptive, anti-inflammatory and antipyretic potential of these plants crude
extracts, to determine the antinociceptive and anti-inflammatory mechanisms of
action, toxicity as well as the phytochemical composition of alkaloid rich
fractions of these plants. Antinociceptive and anti-inflammatory effect assays
were carried out using formalin test and formalin induced paw edema in rats.
Pyrexia was induced in rats using lipopolysaccharid and rectal temperature taken
using a digital thermometer. Alkaloid rich fractions of S. incanum and E.
divinorum were screened using formalin pain and inflammation tests in mice
while antipyretic effect of S. incanum alkaloids was tested on rats. The
antinociceptive mode of action assays involved injection of various receptor
agonists and antagonists which included atropine an antagonist for M2 muscarinic
receptors, and ketamine an N-methyl D-aspartate receptor blocker. Evaluation of
anti-inflammatory mode of actions involved carrageenan leukocyte migration
assay and histamine induced pedal edema. Phytochemical assay was carried out
using standard procedures while LC-QToF MS was used in identification of the
metabolites in alkaloid rich fractions. Extracts from the three plants caused
significant (p < 0.05) anti-inflammatory effects while only the S. incanum and E.
divinorum extract exhibited significant (p < 0.05) antinociceptive effect. The
alkaloids rich fraction of S. incanum exhibited significant antipyretic effect.
Antinociception was significantly attenuated by atropine and ketamine in S.
incanum and E. divinorum alkaloids treated animals respectively. Alkaloids from
S. incanum showed no toxic effect unlike those from E. divinorum. The extracts
contained several types of metabolites of varying quantities. QToF-MS results for
S. incanum showed presence of tri- and tetra glycosides identified as solamargine
and its derivatives E. divinorum contained an unidentified xylose containing
glycosidic alkaloids. Hence S. incanum and E. divinorum contains alkaloids and
perhaps other metabolites with analgesic and anti-inflammatory effects. The
analgesic and anti-inflammatory of S. incanum alkaloids involved inhibition of
M2 receptors and leukocyte migration respectively. E. divinorum alkaloids
inhibited pain via NMDA receptors and inflammation via either or both H1
and H4 receptors. The finding lenders support to traditional use of these plant
parts for relief of pain pain and inflammation. Further investigation may lead to
development of novel drugs for management of these conditions.
Description
A thesis submitted in fulfilment of the requirements forthe award of the degree of doctor of philosophy (medical biochemistry) in the school of pure and applied sciences of Kenyatta University. October; 2016