Stilbene and dihydrophenanthrene derivatives from Pholidota chinensis and their nitric oxide inhibitory and radical-scavenging activities.

Two new stilbene derivatives, ( E)-2′,3,3′-trihydroxy-5-methoxystilbene ( 1, Pholidotol C) and ( Z)-3,3′-hydroxy-5-methoxystilbene ( 2, Pholidotol D), were isolated from the air-dried whole plant of Pholidota chinensis Lindl., together with eight known dihydrophenanthrene derivatives, lusianthridin ( 3), cannabidihydrophenanthrene ( 4), coelonin ( 5), hircinol ( 6), erianthridin ( 7), 4,5-dihydroxy-2-methoxy-9,10-dihydrophenanthrene ( 8), eulophiol ( 9), and 2,4,7-trihydroxy-9,10-dihydrophenanthrene ( 10), and a benzoxepin derivative bulbophylol B ( 11). Their inhibitory effects on nitric oxide (NO) production activity and 1,1-diphenyl-2-picrylhydrazil radical-scavenging activity were examined. Among these compounds, 11 exhibited the most potent activity toward NO production inhibition activity and radical-scavenging activity; moreover, 11 reduced inducible nitric oxide synthase mRNA expression. [ABSTRACT FROM AUTHOR]