Isolation of two flavonol glycosides from Rosa rugosa pollen and their anti-inflammatory effect in lipopolysaccharide-stimulated macrophages

Abstract

Rosa rugosa is a rosaceous plant used in traditional Chinese medicine to treat various diseases, such as rheumatism. Although the chemical constituents of R. rugosa petals have been reported, those of the pollen and their physiological functions remain unclear. In this study, two major compounds were isolated from R. rugosa pollen extracts for the first time, and their structures were identified using instrumental analyses as 8-methoxykaempferol 3-O-sophoroside and 8-methoxykaempferol 3-O-(2″-O-α-L-rhamnosyl)-β-D-glucoside. The anti-inflammatory activity of flavonol glycosides isolated from R. rugosa pollen was evaluated in lipopolysaccharide-stimulated RAW 264 macrophages in vitro. They significantly inhibited nitric oxide release and induced nitric oxide synthase protein expression. They also significantly suppressed the release of inflammatory cytokines, such as interleukin (IL)-1β and IL-6. These results suggest that the two flavonol glycosides in R. rugosa pollen have anti-inflammatory properties.