Antibacterial Effects of Cocoa on Periodontal Pathogenic Bacteria

We examined the antibacterial effects of cocoa on periodontal pathogenic bacteria, including Porphyromonas gingivalis, Fusobacterium nucleatum and Prevotella intermedia, compared with its effects on indigenous oral streptococci. A colony-forming unit (CFU) assay in the presence and absence of 1.0% and 3.0% (w/v) cocoa revealed that the growth of periodontal pathogenic bacteria was significantly suppressed by cocoa in concentration- and incubation time-dependent manners, although cocoa had no effect on the growth of indigenous streptococci. Methanol- and ethanol-extractable fractions from cocoa were also subjected to the CFU assay to determine and characterize the component (s) responsible for these effects. Fractions containing mainly cocoa polyphenols showed antibacterial effects. After treatment with polyvinylpolypyrrolidone, an absorbent of polyphenols, the methanol-extractable fraction lost its effect. These results suggest that cocoa has significant antibacterial effects against periodontal pathogenic bacteria and that polyphenols are responsible.