Antimicrobial and free radical scavenging activities of crude extract and fractions from the tuberous root of Mirabilis jalapa L.

Abstract

Mirabilis jalapa L. belonging to family Nyctaginaceae is a widely used traditional
medicinal plant in different parts of the world. In present study, aqueous methanolic extract and fractions from tuberous root of M. jalapa were evaluated for antimicrobial and free radical scavenging activities. The tuberous
root was extracted in 80 % methanol. Phytochemical constituents were tested following standard procedures which revealed the presence of terpenoids, flavonoids, tannins, steroids, phenolic compounds and alkaloids. The dried extract was further fractionated by using solvents chloroform, ethyl acetate, amyl alcohol, methanol and water. Free radical scavenging capacity was evaluated by 2, 2 diphenyl 1 picrylhydrazine (DPPHô€ˆ©Ë™) and 2, 2’–azinobis (3â€ethylbenzothiazolineâ€6â€sulfonic acid) (ABTS+) assays. IC50 values of extract
were 60±0.71μg/ml and 80±0.56 μg/ml with DPPH and ABTS assays, respectively. Ethyl acetate and amyl alcohol fractions exhibited strong antioxidant activity among the fractions. Antimicrobial activity of extract and fractions was evaluated against selected human pathogens such as Staphylococcus aureus, Streptococcus mutans, Escherchia coli and Candida albicans by agar well diffusion method. The extract and fractions were most active against S. mutans and E. coli. The present study indicated that the root of M. jalapa possess potential antioxidant and broad spectrum antimicrobial activity which could be explored for pharmaceutical applications.