Analgesic and anti-inflammatory activities of the aqueous extracts from three Flemingia species.

I-Tiao-Gung has long been used in the Kinmen area of Taiwan as an anti-inflammatory agent for the treatment of rheumatic illness. The roots of Flemingia lineata (FL), Flemingia macrophylla (FM) and Flemingia prostrata (FP) are also used as I-Tiao-Gung in the Taiwan markets. In the present study, we investigated the analgesic effect of aqueous extracts of Flemingia lineata (FL), Flemingia macrophylla (FM), and Flemingia prostrata (FP) by acetic acid-induced writhing response, formalin test, and the anti-inflammatory effect of FM, FL and FP by lambda-carrageenan-induced paw edema in mice. We also detected the changes in the activities of superoxide dismutase (SOD), glutathione reductase (GRx) and glutathione peroxidase (GPx) of liver in the lambda-carrageenan-induced paw edema in mice to investigate the anti-inflammatory mechanism of FL and FM. The results showed that FL and FM significantly inhibited the acetic acid-induced writhing response and formalin-induced licking time during the late phase (p < 0.001). FL and FM also significantly decreased the lambda-carrageenan-induced paw edema (p < 0.001). FL and FM significantly increased the GRx and GPx activities in the liver and decreased the levels of malondialdehyde (MDA) and nitric oxide (NO) in the edema paw (p < 0.001). These results indicated that FL and FM possessed analgesic and anti-inflammatory effects. The anti-inflammatory mechanism of FL and FM might be related to the decrease in the level of MDA in the edema paw via increasing the activities of GPx and GRx in the liver and decreasing the NO level in the edema paw.