Inhibition of release of inflammatory mediators in rat peritoneal mast cells and murine macrophages by a Chinese herbal medicine formula (RCM-102).

RCM-102 is a Chinese herbal medicine formulation derived from a formula which was shown to be effective in treating seasonal allergic rhinitis (SAR) in a randomized placebo-controlled trial. The aim of this study was to investigate the in vitro effect of RCM-102 on the formation of inflammatory mediators, histamine, prostaglandin and nitric oxide, which are known to be involved in the pathophysiology of SAR. The effect of RCM-102 on histamine release was tested in compound 48/80-stimulated rat peritoneal mast cells. The effects of RCM-102 on the release of NO and prostaglandins (PGE(2)) and the expression of inducible NO synthase (iNOS) and COX-2 were studied in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. In rat peritoneal mast cells, RCM-102 significantly reduced the compound 48/80-induced histamine release. It also significantly reduced NO and PGE(2) production as well as the expression of COX-2 and iNOS in RAW 264.7 cells. These findings indicate that RCM-102 inhibits the formation of several allergic/inflammatory mediators and thus may be used for treating related conditions such as SAR. The actions of RCM-102 are likely to be contributed by the synergistic actions of individual herbal ingredients.