Inhibition by cocoa extracts of biosynthesis of extracellular polysaccharide by human oral bacteria.

Extracts of defatted cocoa inhibited the biosynthesis of extracellular polysaccharide by both cell-free and cell-associated streptococcal glucosyltransferases, but did not affect growth or acid production. Both water-insoluble and water-soluble polysaccharide syntheses were inhibited, and the net result was a shift away from adherence-supportive polysaccharide. Inhibition was non-competitive with respect to sucrose. The inhibition of polysaccharide biosynthesis was observed also with Actinomyces species. The findings suggest that the inhibitory effects of cocoa on plaque accumulation and caries formation are due to inhibition of bacterial polysaccharide production.