Pu'er tea rich in strictinin and catechins prevents biofilm formation of two cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus

Cariogenic bacteria, such as Streptococcus mutans and Streptococcus sobrinus, are main pathogens responsible for human dental caries. Pu'er tea is empirically observed to pre-vent tooth decay. Besides caffeine and catechins commonly found in oolong tea, strictinin is also found as an abundant phenolic compound in Pu'er tea. Infusion of Pu'er tea as well as sin-gle compound, strictinin, caffeine or (-)-epigallocatechin gallate (EGCG) was examined for its inhibitory effects on S. mutans and S. sobrinus. Relatively weak inhibition of bacterial growth was observed for these Pu'er tea constituents. However, biofilm formation of S. mutans or S. sobrinus was strongly prevented by the infusion of Pu'er tea as well as by strictinin or EGCG, but not caffeine. Relatively, strictinin showed a higher potency than EGCG to prevent biofilm formation. Anti-caries effect of Pu'er tea seems to be resulted from the prevention of biofilm formation of cariogenic bacteria mainly by strictinin and catechins. (c) 2021 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).