A New Flavonoid Derivative and Inhibitory Effects on Xanthine Oxidase and -glucosidase from Glinus oppositifolius

In previous studies on bioactivities, some extracts from Glinus oppositifolius possessed antimicrobial, antifungal, antiplasmodial, anti-inflammatory, anti-diarrhoeic, anti-hyperlipidemic, and hepatoprotective. However, information on the xanthine oxidase inhibitors' properties of G. oppositifolius is still limited. For the purpose of discovering new leads with potential alpha-glucosidase inhibition, the less explored plant G. oppositifolius has been investigated. A new apigenin flavone glucoside, named apigenin-5-O-beta-D-glucopyranosyl-8-C-beta-D-glucopyranoside (7), together with seven known compounds (spergulacin (1), glinoside C (2), spergulacin A (3), spergulin B (4), spergulin A (5), vitexin (6), vicenin 2 (8)) were identified from Glinus oppositifolius (L.) Aug. DC. aerial parts. The identification of their structures involved a comprehensive analysis utilizing extensive 1D and 2D NMR techniques, mass spectrometry, and in comparison with those from references. Compound 7 (IC50 =257.90 +/- 1.00 mu M) showed better inhibition of alpha-glucosidase than acarbose (IC50 = 1021.47 +/- 10.79 mu M). Compound 8 (IC50 = 56.82 +/- 1.95 mu M) indicated a good XO inhibitory effect.