Inhibitory effect of Panax notoginseng on nitric oxide synthase, cyclo-oxygenase-2 and neutrophil functions.

A water extract of Panax notoginseng Buck F.H. Chen. (Arialiaceae) root (PN) is being used as a therapeutic agent to stop haemorrhages and as a tonic to promote health in Korean and Chinese medicine. The pharmacokinetic profiles of PN have not been accurately investigated. The preliminary aim was to elucidate the pharmacokinetic features of PN. First, the prevention of neutrophil functions was assessed. PN inhibited neutrophil functions, including degranulation, superoxide generation and leukotriene B4 production, without any effect on 5-lipoxygenase activity. PN reduced nitric oxide (NO) and prostaglandin (PG)E2 production in mouse peritoneal macrophages stimulated with lipopolysaccharide (LPS) while no influence on the activity of inducible NO synthase (iNOS), cyclo-oxygenase-2 (COX-2) or cyclo-oxygenase-1 (COX-1) was observed. PN significantly reduced mouse paw oedema induced by carrageenan. The results indicate that PN exerts antiinflammatory effects related to the inhibition of neutrophil functions and NO and PGE2 production, which could be due to a decreased expression of iNOS and COX-2.