FREE RADICAL SCAVENGING COMPOUNDS FROM DENDROBIUM PARISHII

Abstract

In this study, the EtOAc extract of Dendrobium parishii Rchb. f. was separated to obtain two new compounds including a bibenzyl derivative, 4,3′,4′-trihydroxy-3,5-dimethoxybibenzyl, and a bibenzyl-dihydrophenanthrene derivative, (−)-dendroparishiol, and five known compounds including flavanthrinin, moscatilin, 4,5,4′-trihydroxy-3,3′-dimethoxybibenzyl, dendrocandin E and asiatic acid. The structures of all of the isolated compounds were determined by analysis of spectroscopic data (NMR and HR-ESI-MS). They were then evaluated for antioxidant activities using DPPH free radical scavenging activity, deoxyribose degradation and oxygen radical absorbance capacity assays. Among the tested compounds, (−)-dendroparishiol showed the strongest free radicals reduction and was further investigated for antioxidant activity in H2O2-induced oxidative stress in RAW264.7 murine macrophage cells. (−)-Dendroparishiol could decrease ROS production in RAW264.7 cells in a dose-dependent manner and enhanced the activities of cellular anti-oxidative enzymes (SOD, GPx and CAT). These results indicate that compound (−)-dendroparishiol has the potential to be developed as a useful antioxidant agent.