Inhibition by hop bract polyphenols of cellular adherence and water-insoluble glucan synthesis of Mutans Streptococci

The inhibitory effect of hop bract polyphenols (HBP) on cariogenic streptococci was investigated, It was found that the high molecular weight polyphenol (estimated about 36,000-40,000) inhibited the cellular adherence of Streptococcus mutans MT8148 (serotype C) and Streptococccus sobrinus ATCC 33478 (serotype g) at much smaller concentrations than the polyphenols extracted from oolong tea or green tea leaves, Furthermore, HBP also inhibited the action of glucosyltransferase, which was involved in the water-insoluble glucan synthesis, hut did not suppress the growth and the acid production of the bacteria. These results suggest that HBP would be a candidate to act against dental caries caused by Mutans Streptococci.