α-Glucosidase and xanthine oxidase inhibitory activities from the fruits of Thai <i>Averrhoa bilimbi</i> L.

Averrhoa bilimbi L., a tropical plant native to Southeast Asia, is traditionally used in folk medicine to treat various ailments, including infections, inflammation, hypertension, obesity, and diabetes. In this study, the fruits of A. bilimbi L. were successfully isolated and identified as β-sitosterol (1), zeorin (2), helilandin B (3), 2'-hydroxy-3',4',6'-trimethoxychalcone (4), myricetin (5), quercetin (6), cinchonain Ia (7), syringaresinol (8), and syringaresinol diglucoside (9). All the isolated compounds were tested for their inhibitory effects on α-glucosidase and xanthine oxidase (XO) activities. Compounds 3 and 4 demonstrated the strongest α-glucosidase inhibitory activity, with IC50 values of 4.10 ± 0.20 and 4.79 ± 0.27 µM, respectively. Compound 4 exhibited the highest XO inhibition, with an IC50 value of 48.4 ± 0.03 µM. These findings highlight the potential of the bioactive compounds from A. bilimbi L. as promising candidates for therapeutic applications in the management of diabetes and hyperuricemia.