COMBINATION EFFECTS OF ANTIBACTERIAL COMPOUNDS IN GREEN TEA FLAVOR AGAINST STREPTOCOCCUS-MUTANS

Combinations of green tea flavor compounds with indole were tested for antibacterial activity against Streptococcus mutans, a bacterium responsible for causing dental caries. Synergism was found in the combination of sesquiterpene hydrocarbons (delta-cadinene and beta-caryophyllene) with indole; their bactericidal activities increased from 128-fold to 256-fold. The combination effect was confirmed by time-kill curve assay which showed that 6.25 mug/mL delta-cadinene combined with 400 mug/mL (subinhibitory concentration) indole was bactericidal against S. mutans. Furthermore, the combination of 25 mug/mL delta-cadinene and 400 mug/mL indole reduced the number of viable cells at any stage of growth.