Antioxidant Activities and Protective Effects of Dendropachol, a New Bisbibenzyl Compound from , on Hydrogen Peroxide-Induced Oxidative Stress in HaCaT Keratinocytes.

Five compounds including a new bisbibenzyl named dendropachol () and four known compounds () comprising 4,5-dihydroxy-2,3-dimethoxy-9,10-dihydrophenanthrene (), gigantol (), moscatilin () and 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl () were isolated from a methanolic extract of (Orchidaceae). The chemical structures of the isolated compounds were characterized by spectroscopic methods. Dendropachol () was investigated for its protective effects on hydrogen peroxide (HO)-induced oxidative stress in HaCaT keratinocytes. Compound showed strong free radical scavenging compared to the positive control. For the cytoprotective effect, compound increased the activities of GPx and CAT and the level of GSH but reduced intracellular reactive oxygen species (ROS) generation and accumulation. In addition, compound significantly diminished the expression of p53, Bax, and cytochrome C proteins, decreased the activities of caspase-3 and caspase-9, and increased Bcl-2 protein. The results suggested that compound exhibited antioxidant activities and protective effects in keratinocytes against oxidative stress induced by HO.