ABSTRACT
Ethanolic extract of Annona muricata L., Annonaceae, leaf (AML) was used to investigate its antinociceptive and anti-ulcerogenic activities and the involvement of the mechanism of ethanolic leaves extract of AML in various animal models. Antinociceptive activity of AML extract was done using acetic acid-induced abdominal writhing in mice, formalin test in rats and hot plate test in mice. Furthermore, the anti-ulcerogenic effect of AML extract was studied in ethanol-induced ulcer model in rats, ethanol-induced gastric lesions in L-NAME-pre-treated rats as well as ethanol-induced gastric lesions in NEM-pre-treated rats test model to determine its mechanism. AML exhibited significant and dose-dependent antinociceptive activity. It also significantly decreased the ulcerative lesion produced by ethanol in rats in a dose-dependent manner. Pre-treatment with N-ethymaleimide, a thiol blocker, including mucosal nonprotein sulfhydryl groups, reduced the anti-ulcerogenic effect of AML extract in the same ulcer model, suggesting that AML extract may have active substances such as tannins, flavanoids and triterpenes that increase the mucosal nonprotein sulfhydryl group content.