ANTIBACTERIAL POTENTIAL OF SOME THAI MEDICINAL PLANTS

Abstract

Ethanol and hexane extracts of twenty Thai medicinal plants, used in Thai traditional medicine for the treatment of infectious and septic diseases, were screened in vitro for antibacterial activity against Bacillus cereus, Escherichia coli and Staphylococcus aureus, using disc diffusion method. The ethanol extracts of Clerodendrum inerme (L.) Gaertn., Combretum qurdrangulare L., Psidium guajava Kurz., and Stephania venosa (Blume) Spreng. showed antibacterial activity against all three tested pathogens. Based on minimum inhibitory concentration (MIC) of these four medicinal plant extracts, the ethanol extract of C. inerme demonstrated the highest antibacterial potency. The determination of MIC and minimum bactericidal concentration (MBC) of the extract using microdilution method showed that such extract had MICs for B. cereus, E. coli, and S. aureus of 0.039, 0.312 and 0.156 mg/ml, respectively; and MBCs for B. cereus, E. coli, and S. aureus of 0.039, 0.625 and