Abstract

Plants produce a diverse range of bioactive molecules, making them rich source of different type of medicines. In this study, effect of aqueous, methanol, ethanol and acetone extracts of Stevia rebaudiana leaves were evaluated against Streptococcus mutans. Agar-well diffusion method was used to determine the antibacterial activity of extracts. Minimal inhibitory concentration was obtained by micro-dilution method. The acetone, ethanol and methanol extracts of S. rebaudiana leaves exhibited a concentration dependent on antibacterial inhibition. Acetone and ethanol extracts of Stevia leaf gave the highest zone of inhibition against S. mutans. Aqueous extract of this plant was not effective on S. mutans. Therefore, the findings confirmed the idea that plant extracts of S. rebaudiana leaves may have a role to be used as pharmaceuticals and/or preservatives.

Key words: Antibacterial activity, leaf extract, Stevia rebaudiana, Streptococcus mutans.