Study On Extraction And Activity Of α-glucosidase Inhibitor From The Leaves Of Salix Babylonica

Diabetes is a global disease characterized by hyperglycemia. α-Glucosidase inhibitorscan significantly control the diabetes and its complications by reducing postprandial bloodglucose. So it is very important to isolate effective and safe α-glucosidase inhibitors fromnatural plants. Therefore, the α-glucosidase inhibitory substance with high inhibitory activitywas screened from plants in this research. The α-glucosidase inhibitor from the leaves of Salixbabylonica was investigated, and its hypoglycemic effect on mice was also estimated in thispaper. Foundation for improving the resource utilization rate of Salix babylonica leaves anddeveloping a novel and effective antidiabetic drugs was laid in this study.Firstly, the inhibitory effect on α-glucosidase by extracts from thirty plants wasinvestigated. It was shown that all of the extracts could inhibit the activity of α-glucosidase.At the concentration of100mg/mL, the extract of Salix babylonica leaves exhibited thehighest inhibition (54.38%), followed by Puerariae Radixs (51.59%) and Magnolia officinalisRehd (48.02%). Inhibiton increased with the adding of these three extracts. When theirconcentration reached200mg/mL, the inhibitory activity of Salix babylonica leaves extractwas higher than other extracts.Secondly, Compared with solvent extraction, ultrasonic extraction and microwaveextraction, the ultrasonic-microwave synergistic extraction technology showed a better resultof extraction of α-glucosidase inhibitory substances from Salix babylonica leaves. So theultrasonic-microwave synergistic extraction technology was used to extract inhibitorysubstances and the optimized process was determined as that under the microwave power of150W, added18times of70%(v/v) ethanol into the crude material and extracted270s.Thirdly, inhibitory substances in the crude extract of Salix babylonica leaves wereseparated by liquid-liquid extraction and macroporous resins. It was shown that, the n-butylalcohol fraction exhibited most remarkable inhibitory effect (71.83%). D101resin wasscreened for further purification. The optimum conditions of D101resin were obtained as that10mg/mL sample added under2BV/h flow speed was eluted with4BV50%(v/v) ethanolunder2BV/h flow speed. Then the inhibitory activity was investigated. It was shown that, thecrude inhibitor had a strong α-glucosidase inhibitory activity with an IC50value of0.08123mg/mL, which was less than acarbose (IC50=1.12507mg/mL). The crude inhibitor wasnoncompetitive inhibitory type. The contents of components were preliminarily determined. Itwas shown that, the field of total flavonoids, saponins, tannin and polysaccharide was44.20%,23.54%,13.64%and3.21%, respectively.Finally, the hypoglycemic effect of the crude inhibitor on mice was studied. It wasshown that, the crude inhibitor improved the glucose tolerance of normal and diabetic mice,as well as decreased the fasting blood glucose and TG level of diabetic mice significantly. Butgeneral appearance and body weight of diabetic mice did not show significant changes. In general, the hypoglycemic effect of the crude inhibitor on mice was similar with acarbose.