Inhibitory Effects of Flavonoids from Spatholobus suberectus on Sortase A and Sortase A-Mediated Aggregation of Streptococcus mutans

Seven flavonoids were isolated from via repetitive column chromatography and high-performance liquid chromatography. The chemical structures of these compounds were identified by spectroscopic analysis and comparison with values reported in the literature. Among the flavonoids tested, 7-hydroxy-6-methoxyflavanone ( ) and formononetin ( ) exhibited strong inhibitory activity against SrtA, with IC values of 46.1 and 41.8 µM, respectively, but did not affect cell viability. The onset and magnitude of inhibition of saliva-induced aggregation in treated with compounds and were comparable to the behavior of a -deletion mutant without treatment.