Evaluation of antimicrobial, analgesic, and hypoglycemic activities of Commelina diffusa (Commelinaceae)

Commelina diffusa, also known as the climbing dayflower or spreading dayflower, is an herbaceous plant from the Commelinaceae family, found throughout tropical regions, including Bangladesh. The crude methanol extract and different fractions of C. diffusa were evaluated for their antimicrobial, analgesic, and hypoglycemic activities. The whole plant was extracted with methanol by the cold extraction method. The concentrated extract was then partitioned into petroleum ether- and chloroform-soluble fractions. The antimicrobial test was performed using the disc diffusion method. The analgesic effects were evaluated through both writhing and tail-flick tests at doses of 100 and 200 mg/kg body weight. The oral glucose tolerance test (OGTT) was performed to observe the hypoglycemic effect. The chloroform and methanol soluble fractions showed potent antimicrobial activity against Gram-positive bacteria and fungi. Statistical evaluation of the tail-flick test confirmed that the chloroform soluble fraction (100 mg/kg body weight) of C. diffusa had a significant amount of central analgesic activity (p<0.001). The petroleum ether soluble fraction showed significant central analgesic activity only at higher doses (p <0.01; 200 mg/kg body weight). The acetic acid-induced writhing test also confirmed the peripheral analgesic activity of the samples. The maximum inhibition was noted for the chloroform soluble fraction (64.56%), followed by crude methanolic extract (56.96%) and petroleum ether soluble fraction (53.16%). However, all the extracts showed no significant hypoglycemic activity in the OGTT. This observation, derived from an acute model of non-diabetic animals, does not preclude the possibility of antidiabetic effects in disease-related conditions. Further investigation is warranted to explore the specific metabolites and their pharmacological activities in relevant disease models.