Pharmacological investigation of selected medicinal plants of Bangladesh

Abstract

Purpose: To pharmacologically investigate the methanol and petroleum ether extracts of the plant leaves of Manilkara zapota (MZME and MZPE, respectively), Abroma augusta (AAME and AAPE, respectively) and Vitex negundo (VNME and VNPE, respectively). Methods: Analgesic and anti-diarrheal activities were assessed by acetic acid-induced writhing and castor oil-induced diarrhea in mice, respectively, while CNS depressant activity was evaluated using hole-cross and open-field method by observing the decrease in exploratory behavior and spontaneous motor activity in mice, respectively. Results: All the extracts exhibited good analgesic activity at a dose of 200 mg/kg with the following rank order of activity: MZME > MZPE > VNME > VNPE > AAME > AAPE. Analgesic activity was insignificant at 100 mg/kg dose except for VNPE (67.81% inhibition). The extracts produced significant reduction in diarrheal episodes in mice at a dose of 400 mg/kg MZPE (highest protection: 80.3%, p < 0.05) and VNME (lowest protection: 38.6%, p < 0.001). The extracts demonstrated CNS depressant activity in a dose-dependent manner (p < 0.05 compared to the standard except for AAME and AAPE which showed insignificant activity). Conclusion: The results indicate that the traditional use of the investigated plants appears to be justified; however, further studies are required to unravel the underlying mechanisms of action.