Comparative antimicrobial potential of different extracts of leaves of Stevia rebaudiana Bert.

Abstract

The present investigation was evaluated for potential antimicrobial activity of Stevia rebaudiana leaf extracts, procured from Indian acidic and basic soil zones. Separately Stevia leaves were extracted with aqueous, methanol and ethanol solvents and their microbiocides were compared against few selected gram positive (Bacillus substilis and Staphylococcus aureus) and gram negative bacteria (Escherichia coli, Salmonella typhi) by disc diffusion technique. The study revealed the potential antimicrobial activity of different leaf extracts of Stevia rebaudiana Bert., determined with zone of inhibition against standard amphicilin. However among all the extracts, aqueous leaf extract of Stevia plant having concentration dependent significant antimicrobial activity (P<0.001) compared to extracts collected from basic soil zone. Such results variation may be due to the effect of rich organic carbon content in acidic soil that increase the amount of glycoside content in Stevia leaves. This proved Stevia is a potential antimicrobial agent as non antibiotics sources.