Epigallocatechin gallate (EGCG) suppresses lipopolysaccharide-induced inflammatory bone resorption, and protects against alveolar bone loss in mice

•We examine the role of EGCG, a major polyphenol in green tea, in bone metabolism.•LPS is a pathogen-associated molecule, and induces inflammatory bone resorption.•EGCG suppresses the LPS-induced PGE production in osteoblasts.•EGCG suppresses the LPS-induced bone resorption of alveolar bones in vitro.•In the mouse model of periodontitis, EGCG restores the loss of alveolar bone mass.

Epigallocatechin gallate (EGCG), a major polyphenol in green tea, possesses antioxidant properties and regulates various cell functions. Here, we examined the function of EGCG in inflammatory bone resorption. In calvarial organ cultures, lipopolysaccharide (LPS)-induced bone resorption was clearly suppressed by EGCG. In osteoblasts, EGCG suppressed the LPS-induced expression of COX-2 and mPGES-1 mRNAs, as well as prostaglandin E2 production, and also suppressed RANKL expression, which is essential for osteoclast differentiation. LPS-induced bone resorption of mandibular alveolar bones was attenuated by EGCG in vitro, and the loss of mouse alveolar bone mass was inhibited by the catechin in vivo.