Antimicrobial activity of Streblus asper leaf extract

Bactericidal activity was found in the 50% ethanol (v/v) extract of Streblu s asper leaves. The extract possessed a selective bactericidal activity tow ards Streptococcus, especially to Streptococcus mutans which has been shown to be strongly associated with dental caries. The extract-had no effect on cultures of Escherichia coli, Staphylococcus aureus and Pseudomonas aerugi nosa, Staphylococcus coagulase positive, Staphylococcus coagulase negative, Serratia marcescens, Klebsiella pneumoniae, Enterobacter, Pseudomonas aeru ginosa, Burkholderia pseudomeallei and Candida albicans. The minimum growth inhibitory concentration and the minimum bactericidal concentration of S. asper extract against 10(8) CFU/mL of S. mutans was 2 mg/mL. The active com pound is partially polar, partially heat labile, precipitated by 80% ammoni um sulphate, and possesses a molecular weight larger than 10000 Da. The pot ential for using S. asper extract as a natural product for controlling dent al caries is discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.