Extracción, identificación, caracterización y actividad hipogluceminate de extractos totales y metabolitos secundarios aislados de muehlendeckia tamnifolia (Kunth) Meisn (Polygonaceae), en la provincia de Loja

Abstract

Abstract: Phytochemical investigation of Muehlenbeckia tamnifolia, led to the isolation of nine known compounds identified as: lupeol acetate (1), cis-p-coumaric acid (2), lupeol (3), β-sitosterol (4) trans-p-coumaric acid (5), linoleic acid (6) (+) catechin (7), afzelin (8) and quercitrin (9). The structures of the isolated compounds were determined based on extensive analysis of NMR, MS data, as well as comparison with literature. The hypoglycemic activity of extracts and compounds were assessed by the ability of inhibit a-amylase and a-glucosidase enzymes. Results showed that only the hexanic extract has a weak inhibitory activity on a-amylase, with IC50 of 625 µg mL-1, while the rest of extracts and compounds resulted non active at the maximum dose tested. Although the results on a-glucosidase showed more favorable effects, the hexanic and methanolic extracts exhibited a strong inhibitory activity with IC50 of 48.22 µg mL-1 and 19.22 µg mL-1, respectively. Four of the nine isolated compounds exhibited strong inhibitory activity with IC50 values below 8 µM, much higher than acarbose (377uM). Linoleic acid was the most potent compound (IC50=0.42µM) followed by afzelin, (+) catechin and quercitrin.