The Anti-Inflammatory Properties ofRhododendron molleLeaf Extract in LPS-Induced RAW264.7

Rhododendron molleG.Don is a well-known traditional medicine which has been used to treat rheumatic inflammation. In this study, an inflammatory model of lipopolysaccharide (LPS)-stimulated RAW264.7 cells was established to analyze the anti-inflammatory effect and potential mechanism of the methanol extract ofR. molleleaves (RLE). The production of NO and the expression of tumor necrosis factor by LPS were detected by Griess reaction and enzyme linked immunosorbent assay (ELISA). The mRNA expression ofTNF-alpha,IL-1 beta,IL-6,COX-2andiNOSwas measured by qRT-PCR assay. Griess and qRT-PCR showed that the RLE could significantly concentration-dependently inhibit NO production and the expression of many pro-inflammatory cytokines and inflammatory-related enzymes. Scanning electron microscope (SEM) analysis indicated that RLE could inhibit LPS-stimulated RAW264.7 macrophages activation. The protein level of TNF-alpha and IL-1 beta were decreased over 50 % at 100 mu g/ml of RLE, as detected by ELISA. These results indicated that RLE had strong anti-inflammatory and immunomodulatory activity.