α-Glucosidase Inhibitors from Vauquelinia corymbosa

• Main Authors: Laura Flores-Bocanegra, Araceli Pérez-Vásquez, Mariana Torres-Piedra, Robert Bye, Edelmira Linares, Rachel Mata
• Format: Article
• Language: English
• Published: MDPI AG 2015-08-01
• Series: Molecules
• Subjects: diabetes; yeast and rat α-glucosidases; Vauquelinia corymbosa
• Online Access: http://www.mdpi.com/1420-3049/20/8/15330

The α-glucosidase inhibitory activity of an aqueous extract and compounds from the aerial parts of V. corymbosa was demonstrated with yeast and rat small intestinal α-glucosidases. The aqueous extract inhibited yeast α-glucosidase with a half maximal inhibitory concentration (IC50) of 28.6 μg/mL. Bioassay-guided fractionation of the extract led to the isolation of several compounds, including one cyanogenic glycoside [prunasin (1)], five flavonoids [(−)-epi-catechin (2), hyperoside (3), isoquercetin (4), quercitrin (5) and quercetin-3-O-(6′′-benzoyl)-β-galactoside (6)] and two simple aromatic compounds [picein (7) and methylarbutin (8)]. The most active compound was 6 with IC50 values of 30 μM in the case of yeast α-glucosidase, and 437 μM in the case of the mammalian enzyme. According to the kinetic analyses performed with rat and yeast enzymes, this compound behaved as mixed-type inhibitor; the calculated inhibition constants (Ki) were 212 and 50 μM, respectively. Molecular docking analyses with yeast and mammalian α-glucosidases revealed that compound 6 bind differently to these enzymes. Altogether, the results of this work suggest that preparations of V. corymbosa might delay glucose absorption in vivo.