Anti-rheumatoid arthritic activity of flavonoids from Daphne genkwa

The aim of the study was to investigate the anti-rheumatoid arthritic activity of four flavonoids from Daphne genkwa (FFD) in vivo and in vitro. Flavonoids of D. genkwa were extracted by refluxing with ethanol and purified by polyamide resin. An in vivo carrageenan-induced paw edema model, tampon-granuloma model and Freund's complete adjuvant (FCA)-induced arthritis mouse model were used to evaluate the anti-rheumatoid arthritic activities of FFD. Moreover, nitric oxide (NO) release and neutral red uptake (NRU) in lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cells were used to evaluate the anti-inflammatory effect in vitro. In addition, antioxidant effect of FFD was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. A high dose of FFD significantly reduced the degree of acute inflammatory paw edema in mice as a response to carrageenan administration (p<0.01). FFD displayed a dose-dependent inhibition of granuloma formation in mice (p<0.05). FFD also inhibited chronic inflammation in adjuvant-induced arthritis rats when administered orally at the dose of 50mg/kg/day (p<0.001). In addition, FFD suppressed the production of NO and exhibited immunoregulatory function in LPS-activated RAW264.7 cells in a dose-related manner. Simultaneously, FFD revealed conspicuous antioxidant activity with IC50 values of 18.20μg/ml. FFD possesses significant anti-inflammatory and antioxidant activity, which could be a potential therapeutic agent for chronic inflammatory disorders such as rheumatoid arthritis.