Biologically active constituents of Arnebia euchroma: structure of arnebinol, an ansa-type monoterpenylbenzenoid with inhibitory activity on prostaglandin biosynthesis.

Three phenolic compounds were isolated from the roots of Arnebia euchroma as inhibitors of in vitro prostaglandin biosynthesis. Two known compounds were identified as shikonofurans and des-O-methyllasiodiplodin. The other new compound was named arnebinol and its structure was elucidated as a novel ansa-type monoterpenylbenzenoid derivative.