Xanthine Oxidase Inhibitory, Anti-inflammatory, and Analgesic Activities of Kaempferia galanga L. Extracts: Experimental Studies

Objectives: This study aimed to evaluate the analgesic, anti-inflammatory, and antihyperuricemic properties of Kaempferia galanga L. extract (KgE) using several animal models. Materials and Methods: To investigate the anti-hyperuricemic activity of KgE in vivo, hyperuricemia was induced in mice using potassium oxonate. The mechanism underlying the uric acidlowering effect was explored by assessing Xanthine Oxidase (XO) inhibitory activity in vitro. The analgesic effect of KgE was evaluated in mice using the hot plate test, Von Frey test, and acetic acid-induced writhing test. The anti-inflammatory activity was assessed in rats by measuring paw edema induced by carrageenan injection. Results: KgE demonstrated significant XO inhibitory activity in vitro, with the Hex fraction identified as the most effective. Consequently, all doses of the Hex fraction significantly reduced uric acid levels in the serum and urine of hyperuricemic mice. In analgesic tests, the Hex fraction significantly reduced the writhing response in the acetic acid-induced test. However, it did not increase the pain threshold in the hot plate and Von Frey tests, indicating no significant effect on thermal and mechanical pain stimuli. Additionally, the Hex fraction did not significantly inhibit carrageenan-induced paw edema. Following the observation of strong XO inhibitory activity in vitro, two bioactive compounds were isolated and identified: ethyl trans-4-methoxycinnamate (1) and (1S,5S,9S,10S,11R,13R)-1,11-dihydroxypimara-8(14),15-diene (2). Conclusion: The Hex fraction of KgE demonstrated peripheral analgesic and anti-hyperuricemic activities in experimental animal models.