Anti-arthritic activity of ethanol extract of Fagopyrum cymosum with adjuvant-induced arthritis in rats.

CONTEXT: Fagopyrum cymosum (Trey.) Meisn (Polygonaceae) (EFC) has long been used as a folk medicine to treat various ailments of the lung, dysentery and rheumatism in China.

OBJECTIVE: The present study evaluated the anti-arthritic effect of 95% ethanol extract of EFC (extract of Fagopyrum cymosum).

MATERIALS AND METHODS: The anti-arthritic activity was investigated by adjuvant arthritic (AA) rat model induced by Freund's complete adjuvant (FCA). The AA rats were randomly separated into different groups and then treated with EFC (40, 80 and 160 mg/kg) from day 7 to day 28 after immunization. Arthritis was evaluated by hind paw swelling, polyarthritis index, body weight and index of immune organs. In addition, the severity of arthritis in the knee joints was evaluated by histopathological and hemorheological examination. The levels of interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-α) in the serum were assessed by ELISA.

RESULTS: The high dose level of EFC (160 mg/kg) significantly suppressed the swelling of hind paw of AA rats (p < 0.01) and inhibited their body weight loss (p < 0.01). Based on histopathological examination, all EFC groups showed great amelioration compared with the model group. EFC (80 and 160 mg/kg) also decreased the plasma viscosity in different shear rates (p < 0.01). Moreover, EFC significantly reduced the production of IL-1 and TNF-α in the serum of AA (p < 0.01).

DISCUSSION AND CONCLUSION: This study provides a scientific basis for the claims that F. cymosum is effective in preventing and suppressing the development and progression of experimental arthritis, with reductions in inflammatory response.