Evaluation of Total Flavonoid Content, Xanthine Oxidase Inhibition, and Uric Acid Inhibitory Activity In Vitro and In Vivo of Ethanol Extract of Sidaguri (Sida rhombifolia L.)

Secondary metabolites content in Sida rhombifolia L. (SR) are believed to inhibit the xanthine oxidase (XO) enzyme, which is responsible for converting hypoxanthine and xanthine into uric acid. This study aimed to compare flavonoid levels, XO inhibitory activity, and the reduction of uric acid levels of sidaguri herb, stem, leaves, and root extract both in vitro and in vivo. The research results showed that the highest total flavonoid content in SR was found in the leaves, at 21.29±0.08 mg/QE/g extract. The IC50 values were as follows: roots (EESRR 1096.07±1.07 ppm), stems (EESRS 561.62±7.01 ppm), leaves (EESRL 101.84±0.63 ppm), and herbs (EESRH 104.70±3.50 ppm). EESR can inhibit the XO enzyme and has potential as an anti-hyperuricemia agent. The best total flavonoid content and IC50 values were observed in EESRL, which are 21.29±0.08 mg/QE/g and 101.84±0.63 ppm, respectively. EESRL at a dose of 400 mg/kg BW has the equivalent ability to reduce blood uric acid levels in mice when compared to the positive control group. Based on these findings, it can be concluded that EESRL has significant potential as a natural XO inhibitor and can be considered a promising candidate for the development of anti-hyperuricemia treatments.