Antioxidant activity of Rosa multiflora Thunb. flower extract and suppressive activity on proinflammatory mediator production in lipopolysaccharide- stimulated RAW 264.7 macrophages

Abstract

Background: Oxidative stress and inflammation are associated with various ageing-related chronic diseases. The fruits and roots of Rosa multiflora Thunb. have been used in medicine for the treatment of edema and inflammatory diseases in Eastern Asia. Dried Rosa multiflora Thunb. flower (RMF) have been consumed as a tea in Korea, but reports on the biological activity of RMF are lacking. We evaluated the in vitro antioxidant and anti-inflammatory effects of an ethanol extract from RMF as well as various solvent fractions from the extract.Methods: The ethanol extract (Et) of RMP was fractionated sequentially by hexane (Hx), dichloromethane (DM), ethylacetate (EA), n-butanol (Bt) and distilled water (DW). Total phenolic content and total flavonoid content, scavenging activities of the 2,2-diphenyl-1 picrylhydrazyl radical and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical and ferric-reducing antioxidant power were measured. Anti-inflammatory effects in terms of levels of nitric oxide and prostaglandin (PG) E2 and production of proinflammatory cytokines such as interleukin (IL)-6, tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages were measured, and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were measured by Western blot analysis.Results: EA treatment showed the highest total phenolic and total flavonoid content and strongest antioxidant activity, followed by Bt and Et, measured by three different methods. Treatment with Et and all fractions significantly suppressed (p<0.05) nitric oxide production in a dose-dependent manner in LPS-treated RAW 264.7 macrophages via reduction of expression of iNOS protein. Treatment with Et, DM and EA significantly suppressed (p<0.05) PGE2 production induced by LPS treatment, however, only Bt treatment significantly reduced (p<0.05) the expression of COX-2 protein. Treatment with DM, EA and Bt suppressed IL-6 production significantly (p<0.05) in LPS-treated RAW 264.7 macrophages, and treatment with Et, DM, EA and Bt suppressed TNF-α production significantly (p<0.05).Conclusions: These data suggest that the ethanol extract of Rosa multiflora Thunb. flower and its dichloromethan, ethylacetate and n-butanol fractions have potent antioxidant and/or anti-inflammatory activities.Keywords: Rosa multiflora Thunb. flower, antioxidant activity, anti-inflammatory activity, RAW 264 7 macrophages, cytokines, iNOS, COX-2