Antimicrobial and antidiarrhoeal activities of aqueous and methanolic extracts of Mangifera indica Linn stem bark (Anarcadiaceae) in Wistar rats

Abstract

Diarrhea is one of the leading causes of infant mortality in developing country. It has been reported that Mangifera indica is used as an antidiarrhoeal agent in traditional medicine. Thus, the aim of this study was to evaluate the antimicrobial and antidiarrhoeal activities of aqueous and methanolic extracts of Mangifera indica Linn stem bark. The extracts were tested in vitro on the growth of bacteria and fungi; and in vivo at doses of 300, 400 and 500 mg/kg on the effects of Escherichia coli, castor oil, misoprostol and charcoal meal in rats. In vitro, the methanolic extract was the most active with a minimum inhibitory concentration (MIC) of 256 µg/mL for all Gram negative and Gram postive bacteria tested; the value of MIC for all fungi tested was 32 µg/mL. In vivo, the aqueous extract at doses of 300 and 500 mg/kg and methanolic extract at dose of 500 mg/kg resulted in a significant decrease (p < 0.001) in the bacterial load in rats faeces. A significant reduction (p < 0.001) of diarrhoeal parameters was observed with both extracts after castor oil administration. The gut motility was significantly (p < 0.05) reduced with all doses of methanolic extract. Both extracts significantly (p < 0.001) reduced the increase of intestinal fluids volume induced by misoprostol. Histopathological analysis revealed few abnormalities in the structure and morphology of the ileum after treatment of rats with aqueous and methanolic extract. This study showed that Mangifera indica possesses antimicrobial and antidiarrheic properties and attest its usefulness in traditional treatment of gastrointestinal infection.