Bioassay-guided isolation of α-glucosidase inhibitors from Byrsonima garcibarrigae Cuatrec.

Introduction:Byrsonima garcibarrigae is an endemic tree of Amazonas state, Brazil, with pharmacological and chemical knowledge poorly understood. Aim: To investigate the antidiabetic potential of the B. garcibarrigae stem bark. Methods: The stem bark was sequentially extracted by maceration with hexane (EHBG), ethyl acetate (EABG), and methanol (EMBG). The antioxidant capacity, α-glucosidase inhibitory potentials and anti-glycation capacities were evaluated. A bio-guided fractionation gave compounds that were characterized by MS and NMR. Results: 8 compounds were identified by HPLC-MS. EMBG showed the highest α-glucosidase inhibitory activity (1.09±0.32 μg/mL), antioxidant activity (9.2±0.23 μg/mL) and phenolic compounds content (61.43±0.50%), thus was fractionated producing hexane (FHX), chloroform (FCL) and hydromethanolic (FHM) fractions. After additional anti-α-glucosidase assays, FHM (1.02±0.49 μg/mL) was fractionated giving quercitrin and epicatechin. The anti-glycation assay showed that EMBG, FHM and quercitrin presented higher activities in comparison to the positive control, aminoguanidine. Conclusions:B. garcibarrigae displayed antidiabetic potential since inhibited α-glucosidase, as well as presented expressive antioxidant and anti-glycation activities were recorded.