Effect of propolis phenolic compounds on free fatty acid receptor 4 activation.

Propolis is known to have multiple biological and pharmacological properties including the regulation of energy homeostasis. Although phenolic compounds are considered to be the major active components in propolis, there is little information available about their mechanisms underlying the regulation of energy homeostasis. In this study, the effects of five phenolic compounds in propolis, chrysin, pinocembrin, galangin, pinobanksin, and caffeic acid phenethyl ester (CAPE) were evaluated on the activation of free fatty acid receptor 4 (FFA4), which are involved in the control of energy homeostasis by enhancing insulin signaling, increasing glucose uptake, and regulating adipogenesis. The results showed that three phenolic compounds exhibited the activation of FFA4, which were ranked in the order of pinocembrin, CAPE and pinobanksin in FFA4-expressing cells. These results suggest that some phenolic compounds in propolis, particularly pinocembrin, may affect the control of energy homeostasis via the activation of FFA4.