Sterols isolated from seeds of Panax ginseng and their antiinflammatory activities

BACKGROUND: Panax ginseng C. A. Meyer, a perennial herb from the Araliaceae family, is a commonly used medicinal plant. Many studies have been conducted on the biologically active constituents of whole parts of P. ginseng (i.e., roots, leaves, flower buds, and fruits). However, the seeds of P. ginseng have not been intensively investigated. A new sterol glucoside,3-O-b-d-glucopyranosyl-5,22,24-stigmastatrienol (1), and a known sterol, 5,22-stigmastadienol (2), were isolated from seeds of P. ginseng and were evaluated for their inhibitory activities on tumor necrosis factor (TNF)α-induced nuclear factor (NF)-κB and inducible nitric oxide synthase (iNOS) transcription in transfected HepG2 cells. The present work deals with the isolation, identification, and antiinflammatory activities of the two compounds. MATERIALS AND METHODS: The compounds were isolated by a combination of silica gel and YMC R-18 column chromatography, and their structures were identified by analysis of spectroscopic data (1D, 2D-NMR, and MS). The antiinflammatory activities of the isolated compounds 1 and 2 were evaluated by luciferase reporter gene assays. RESULTS: Two sterols have been isolated from the seeds of P. ginseng. Compound 1 is a previously unreported glucosidyl sterol. Compounds 1 and 2 both inhibited NFκB-luciferase activity, with IC(50) values of 8.1 and 4.8΅M, respectively. They also inhibited iNOS-luciferase activity in TNFα-induced HepG2 cells, with IC(50) values of 2.2 and 2.9΅M, respectively. CONCLUSION: The two isolatedsterols have inhibitory effects on inflammation-related factors in HepG2 cells, as determined by luciferase reporter gene assays. Thus, seeds of P. ginseng are worthy of consideration for the development and research of antiinflammatory agents.