Abstract
Gout is a metabolic diseases usually characterized by recurrent attacks of acute inflammatory arthritis. It is caused by elevated levels of uric acid in the blood which crystallize and are deposited in joints, tendons, and surrounding tissues. Xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and then to uric acid, which plays a crucial role in hyperuricemia. Chrysanthemum indicum Linn is one of the popular traditional herbs extensively used in Taiwan and Chinese medicine. The herb have been used to treat various immune-related disorders, hypertension symptoms and several infectious diseases. In this study, we investigated effects of C. indicum extracts on xanthine oxidase activity, a key enzyme in uric acid synthesis, uric acid levels in hyperuricemic rats. The results demonstrated that the ethyl acetate extract of C. indicum presented the strongest xanthine oxidase inhibition activity (IC50=30.3 μg/mL). However, no significant xanthine oxidase inhibition activities were found in the hexane and water extracts. We also found that administration of a single dose of 300 mg/kg ethyl acetate extract of C. indicum to such animals reduced the serum uric acid concentration to 2.28 ± 0.13 mg/dL, compared with a concentration of 4.40 ± 0.08 mg/dL in the hyperuricemic control group.