ANTISECRETORY ACTIVITY OF THE STEM BARK AQUEOUS EXTRACT OF KHAYA GRANDIFOLIOLA (MELIACEAE) IN RATS OCCURS THROUGH ANTICHOLINERGIC AND ANTIHISTAMINIC PATHWAYS

Désirée Sandrine Mbida Essama*, Gustave Lebeau Ndji Otto, Christophe Mezui and Paul Vernyuy Tan

ABSTRACT

Aim: The current study investigated the possible mechanism of antisecretory action of Khaya grandifoliola in rats. Methods: Carbachol and histamine-induced hypersecretion, associated with the pylorus ligation technique, were used. The aqueous extract (250-500 mg/kg) was administered by oral or duodenal route and gastric mucosal ulceration, mucus production, pH, gastric volume, and acidity were measured. Results: Histamine and carbachol raised gastric acidity to 68.89 and 60.00 mEq/L respectively in the control rats. The extract of K. grandifoliola (250 and 500 mg/kg), given by oral route significantly (p< 0.001) reduced histamine-induced gastric acidity to 41.80 and 40.60 mEq/L, and carbachol-induced gastric acidity to 24.42 and 16.40 mEq/L, with 100 percent inhibition of gastric ulceration by the 500 mg/kg dose in the carbachol model. Intraduodenally-administered extract (250-500 mg/kg) significantly (p < 0.001) reduced histamine-induced gastric acidity to 48.73 and 33.84 mEq/L, and carbachol-induced gastric acidity to 26.72 and 26.22 mEq/L. The extract (250-500 mg/kg) significantly reduced (p < 0.001) the volume of gastric secretion and significantly increased mucus production in carbachol-induced hypersecretion only. The ulcer inhibition potential in histamine-induced gastric lesion, at the two doses of the extract of K. grandifoliola, was low (20.79 % and 48.97 %) by oral route, but increased by intraduodenal route (53.92 % and 83.03 %). In carbachol-induced gastric lesion, 250 mg/kg of extract increased ulcer inhibition potential from 29.93 % by oral route to 67.49 % by duodenal route Conclusion: The aqueous extract of K. grandifoliola has both antisecretory and cytoprotective effects. This antisecretory effect may involve a mechanism common to both cholinergic and histaminic pathways with greater effects elicited through the cholinergic pathway.

Keywords: Khaya grandifoliola, gastric ulcer, gastric hypersecretion, antisecretory activity.