H. Muroi et I. Kubo, COMBINATION EFFECTS OF ANTIBACTERIAL COMPOUNDS IN GREEN TEA FLAVOR AGAINST STREPTOCOCCUS-MUTANS, Journal of agricultural and food chemistry, 41(7), 1993, pp. 1102-1105
Combinations of green tea flavor compounds with indole were tested for
antibacterial activity against Streptococcus mutans, a bacterium resp
onsible for causing dental caries. Synergism was found in the combinat
ion of sesquiterpene hydrocarbons (delta-cadinene and beta-caryophylle
ne) 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 m
ug/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 g
rowth.