ANTIMICROBIAL ACTIVITY OF TEA EXTRACTS AG AINST PERIODONTOPATHIC BACTERIA

The antimicrobial activities of three kinds of green tea extracts, an ethanol extract, a crude catechin extract and (-)-epigallocatechingall ate (EGCg) extract, were studied by calculation of the minimum inhibit ory concentrations (MIC) against eight species of periodontopathic bac teria such as Porphyromonas gingivalis, the most common periodontopath ic bacterium in adults. A suitable growth medium for each bacterium wa s identified in preliminary tests. A glucose-mineral-biotin medium was selected for use as the basic medium and a small amount of brain-hear t-infusion broth was added as necessary. The growth of all bacteria te sted was inhibited by each extract. The EGCg extract had the lowest MI C. Against P. gingivalis, the MIC was 5.0 mg/ml. Against the other bac teria, the MIC was less than 1.0 mg/ml.