Anti-inflammatory effects of the roots of Alpinia pricei Hayata and its phenolic compounds

Abstract

Alpinia pricei Hayata is cultivated throughout Asia and is an endemic plant in Taiwan. The leaf and root of this plant are used for traditional wrapping of food and as a cooking substitute for fresh ginger. The aim of this work was to study the in vitro anti-inflammatory effects of ethanol extracts from A. pricei Hayata (EEAP) and its phenolic compounds. High-performance liquid chromatography (HPLC) profiling indicated that EEAP contained caffeic acid, chlorogenic acid, ferulic acid, p-hydroxybenzoic acid, rutin, apigenin, curcumin and pinocembrin. EEAP and its phenolic compounds, apigenin, curcumin, and pinocembrin, inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production in RAW 264.7 cells. Furthermore, EEAP, apigenin, curcumin, and pinocembrin decreased LPS-mediated induction of protein and mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. In addition, EEAP and its major active compound pinocembrin inhibited LPS-induced nuclear translocation of nuclear factor-kappaB (NF-kappaB) and NF-kappaB-mediated reporter gene expression. EEAP and pinocembrin also significantly inhibited LPS-induced intracellular reactive oxygen species (ROS) production in RAW 264.7 cells. When these results are taken together, they indicate that EEAP and pinocembrin suppressed LPS-induced NO and PGE(2) production by inhibition of NF-kappaB nuclear translocation and ROS generation.