Isopanduratin A from Kaempferia pandurata as an active antibacterial agent against cariogenic Streptococcus mutans

An antibacterial compound active against Strepococcus mutans was isolated from Kaempferia pandurata and identified as isopanduration A using H-1 NMR, C-13 NMR and El-MS. The minimum inhibitory concentration (MIC) of isopanduration A was 4 mg/l which was much lower than that os some other natural anticariogenic agents such as sanguinarine (12 mg/l), green tea extract and carvacrol (125 mg/l), thymol (250 mg/l) and isoeugenol and eucalyptol (500 mg/l). The bactericidal test showed that isopanduratin A completely inactivated S. mutans at 20 mg/l in 1 min. Significant inhibitory activity of isopanduration A was also observed against S. sobrinus, S. sanguinis and S. salivarius with an MIC of 4 mg/l. Damage to the cell membrane and cell wall of S. mutans by ispoanduration A was shown using transmission electron microscopy (TEM). These results suggest that isopanduratin A could be employed as a potential antibacterial agent for preventing dental caries. (C) 2003 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.