Inhibitors of nitric oxide production from the bark of Myrica rubra: structures of new biphenyl type diarylheptanoid glycosides and taraxerane type triterpene.

Three new biphenyl type diarylheptanoid glycosides, myricanol 11-O-beta-D-glucopyranoside, myricanone 5-O-beta-D-glucopyranoside, and neomyricanone 5-O-beta-D-glucopyranoside, and a new taraxerane type triterpene, myricetrione, were isolated from the bark of Chinese Myrica rubra. Their structures were elucidated on the basis of chemical and physicochemical evidence. Biphenyl type diarylheptanoids, triterpene, and their polyphenols showed potent inhibitory effects on nitric oxide production in lipopolysaccharide-activated macrophages. Furthermore, diarylheptanoids, myricanol and myricanone, were found to inhibit induction of inducible nitric oxide synthase.