Selected Thai traditional polyherbal medicines suppress the cariogenic properties of Streptococcus mutans by disrupting its acid formation and quorum sensing abilities

Abstract

Ethnopharmacological relevanceThirty-five herbal formulations used in this current work are utilized as anti-cariogenic agents in Thai traditional medicine. Acidogenic properties play a crucial role in the initiation of dental caries caused by Streptococcus mutans, and a quorum sensing (QS) system is an associated virulence factor in dental caries. Aim of the studyThe current work aimed to determine the anti-acidogenic effect of these polyherbal formulas against S. mutans and explore their anti-QS activity using Chromobacterium violaceum as a biosensor. Materials and methodsEthanol and water extracts from the formulas were evaluated for their anti-acidogenic effects using glycolytic pH drop assays. Qualification and quantification of anti-QS activity indicated by the level of violacein production in C. violaceum were performed using paper disc-diffusion and flask incubation assays, respectively. ResultsAmong the extracts tested, THF-DC 02 and THF-DC 04 significantly inhibited the acidogenesis of S. mutans in a dose-dependent manner without affecting the cell viability. THF-DC 20 and THF-DC 29 sharply reduced the violacein production of C. violaceum, indicating the promising anti-QS activity of these extracts. ConclusionThe findings of the present study, preliminarily propose that the polyherbal formulas THF-DC 02, THF-DC 04, THF-DC 20, and THF-DC 29 produce promising anti-acidogenic or anti-QS activities. The anti-acidogenic effect of THF-DC 04 may possibly act by interrupting streptococcal membrane enzymes via its herbal components: Alpinia galanga (L.) Willd., Albizia myriophylla Benth., Avicennia marina subsp. eucalyptifolia (Valeton) J.Everett and Ocimum tenuiflorum L. The anti-QS activity of THF-DC 20 and THF-DC 29 could be due to their herbal ingredients, including Piper betle L., Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz., and Syzygium aromaticum (L.) Merr. & L.M.Perry.