Antibacterial and antioxidant effect of ethanol extracts of Terminalia chebula on Streptococcus mutans

Dental caries is a high prevalent chronic bacterial infectious disease caused by plaque, a bacterial colony deposited on tooth surfaces and gum tissues. Streptococcus mutans is a primary cariogenic bacterium commonly found in the human oral cavity. Oral hygiene products containing antibacterial ingredients can be helpful in caries management. In this study, we investigated the anticaries mechanism of the ethanol extract of Terminalia chebula (EETC) on S. mutans and suggest its possible application as a functional ingredients for oral hygiene products.

The EETC was prepared from the Terminalia chebula fruit. Disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and colony forming unit (CFU) were analyzed to observe the antibacterial activity of EETC. The glucan formation was measured using the filtrate of bacterial culture medium and sucrose. Gene expression was analyzed using RT-PCR. Cytotoxicity was analyzed using the MTT assay. The radical-scavenging activities of DPPH and ABTS were also tested to verify the antioxidant activity of EETC.

The antibacterial activity of the EETC was explored through a disc diffusion analysis and CFU measurement. EETC treatment decreased insoluble glucan formation and gene expression of glycosyltransferase B (gtf B), glycosyltransferase C (gtf C), glycosyltransferase D (gtf D), and fructosyltransferase (ftf). The MIC and MBC of EETC on S. mutans were not cytotoxic to gingival fibroblasts. In addition, we observed DPPH and ABTS-radical scavenging activities of EETC.

These results indicate that the antibacterial and antioxidant effects of EETC may contribute to oral hygiene products for dental caries management.