Antimicrobial activity of ethanol extracts of Agaricus brasiliensis against mutans streptococci

Abstract

This study evaluated the antimicrobial activity of three different ethanol extracts of Agaricus brasiliensis S. Wasser et al. (Agaricaceae) on the growth and cell adherence of mutans streptococci. Crude ethanol extracts (100% EtOH, 75% EtOH, and 50% EtOH, v/v) obtained from dried basidiomes of A. brasiliensis were assessed against Streptococcus mutans UA159 and Streptococcus sobrinus 6715 by the agar diffusion method, determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and inhibition of cell adherence to a glass surface. In the agar diffusion method, only the 100% ethanol extract revealed inhibition of bacterial growth. Yet, in MIC and MBC tests, the three extracts presented antimicrobial properties and MIC and MBC values between 87.4 and 444.5 μg mL-1. The MBC was predominantly similar to MIC against S. mutans, but only the 75% ethanol extract was bactericidal against S. sobrinus. Among the ethanol extracts tested, the 100% ethanol extract was the most active (MIC 87.4 μg mL-1). The cellular adherence also was inhibited at concentrations from 100 to 400 μg mL-1 of 50% and 75% ethanol extracts. These results provide promising baseline formation for the potential use of A. brasiliensis against mutans streptococci. These findings warrant more in-depth studies of the active principles of this mushroom ethanol extract. © 2009 Informa UK Ltd.