Inhibition of prostaglandin and nitric oxide production in lipopolysaccharide-treated RAW 264.7 cells by tanshinones from the roots of Salvia miltiorrhiza bunge.

This study examined the effects of tanshinone derivatives (tanshinone I, cryptotanshinone, 15,16-dihydrotanshinone I) on prostaglandin (PG) and nitric oxide (NO) metabolism in an attempt to establish their anti-inflammatory mechanisms and to present a scientific rationale for the use of Salvia miltiorrhiza (danshen) in inflammatory conditions. From lipopolysaccharide-treated RAW 264.7 cells, cyclooxygenase-2 (COX-2)-mediated PGE2 production was inhibited by tanshinone I, cryptotanshinone and 15,16-dihydrotanshinone I, while only cryptotanshinone and 15,16-dihydrotanshinone I inhibited inducible NO synthase (iNOS)-mediated NO synthesis at 1-50 microM. Particularly, cryptotanshinone was found to be a down-regulator of proinflammatory molecule expression, including COX-2 and iNOS. The electrophoretic mobility shift assay showed that cryptotanshinone and 15,16-dihydrotanshinone I also inhibited the activation of the transcription factors, such as nuclear transcription factor-kappaB and activator protein-1. Moreover, cryptotanshinone exhibited in vivo anti-inflammatory activity against carrageenan-induced paw edema in rats. Overall, these results provide additional scientific rationale for the anti-inflammatory use of danshen in Chinese medicine. Especially, cryptotanshinone and 15,16-dihydrotanshinone I are important constituents.