In vitro antibacterial effects of the crude extracts of Sophora alopecuroides against oral microorganisms

Sophora alopecuroides is widely used in Mongolian traditional medicine. The antimicrobial effects of the methanolic and aqueous extracts of its roots against Streptococcus mutans, Streptococcus sobrinus and Staphylococcus aureus were examined in vitro. Four fractions were obtained from methanol extract and labeled as Fractions-1, 2, 3, and 4. The MIC's and MBC's of the crude extracts of Sophora alopecuroides were determined, and bacterial cell growth curves in the presence of Fractions-1, 3, and 4 were drawn. Among the methanolic extracts, the extracts of Fractions-1, 3, and 4 possessed strong inhibitory effect on the growth of mutans streptococci and S. aureus. Fraction-2 and the aqueous extracts of S. alopecuroides had weak antibacterial activities. Thus, S. alopecuroides would be useful for the suppression of oral pathogens, and has potential for use in the prevention of dental caries and treatment of diseases caused by S. aureus.