| alpha-glucosidases are important in a broad range of metabolic pathways, including glycoprotein and glycolipid processing and carbohydrate digestion in the intestinal tract, so they are postulated to be a powerful therapeutic target for the treatment of diabetes, human immunodeficiency virus (HIV) infection, metastatic cancer, and lysosomal storage diseases.Laminaria japonica (Kelp) are large seaweeds (algae), belonging to the brown algae and classified in the order Laminariales. In some regions of China, the root of kelp has been used as a kind of civilian anti-diabetic drug for a long time. It is significant to extract and isolate anti-diabetes compounds from the root of Laminaria japonica.In this study, the methanol extract of kelp root was extracted by petroleum ether, ethyl acetate, and n-butanol according to the polarity successively. The IC50 of every fraction was determined. The results suggested that the IC50 of five extracts against alpha-glucosidase were 1589μg/L, 970μg/L, 380μg/L, 1616μg/L, 1106μg/L, respectively. Compared with others, the IC50 of ethyl acetate fraction was the highest.Secondly, the ethyl acetate fraction was treated to STZ induced diabetic mice. The results suggested that ethyl acetate fraction of kelp root has remarkable anti-hyperglycemic activity, at the dose of 500mg/kg, statistically different with standard group. In conclusion, kelp root has anti-diabetic activity in vivo.Guided by the alpha-glucosidase inhibitory test in vitro, we further isolated and identified butyl-isobutyl-phthalate by means of physicochemical constants and spectral analysis. Butyl-isobutyl-phthalate had strong alpha-glucosidase inhibitory activity and was a noncompetitive alpha-glucosidase inhibitor with a IC50 of 13.6μg/mL, and Km value of 2.39 g/L.The results of this study provide a reference for the further study on Laminaria japonica about mechanism of lowering plasma glucose and application of new preparation.
|
PDF Full Text Request