New <i>α</i> ‐Glucosidase Inhibitors from Vietnamese <i>Garcinia schomburgkiana</i> Fruits

The chemical investigation of the fruits of Garcinia schomburgkiana growing in Vietnam led to the isolation of a new anofinic acid derivative, 5-hydroxy-8-methoxyanofinic acid (1), a new xanthone, xanthoschome C (2), and a known synthetic phenolic analog, 4-(2-hydroxybenzyl)-2-(4-hydroxybenzyl) phenol (3), along with seven known xanthones (4-10). The structures of all isolated compounds were determined using spectroscopic techniques (nuclear magnetic resonance and mass spectrometry), in conjunction with a comparison to existing literature data. All isolated compounds were assessed for their α-glucosidase inhibitory activity and showed significant inhibition, with half-maximal inhibitory concentration (IC₅₀) values ranging from 12.1 to 65.7 µM, surpassing the potency of the positive control, acarbose (IC₅₀ 179 ± 6.02 µM). Among them, compound 8 exhibited the strongest inhibitory activity, with an IC₅₀ value of 12.1 ± 0.44 µM.