Studies On Extraction, Isolation And Bioactivity Of Dihydromyricetin In Ampelopsis Grossendentata

Ampelopsis grossedentata, a wild plant, belongs to Ampelopsis Michx of Vitaceae. It contains abundance of flavone, which can highly reach to 40%, while dihydromyricetin can achieve 27%, so great attention was paid to Ampelopsis grossedentata. In this article, systemic research was performed on the extraction, isolation, hyperglycemia lowering and antioxiditivity of dihydromyricetin. The results were as followed:1. Extraction, Isolation and Structure Analysis of DihydromyricetinIt was ethanol that used as the solvent to extract flavone from Ampelopsis grossedentata, experiment factors and levels were firstly selected by one-factor tests. Next on the basis of this and according to the two-level experiment, the method of Response Surface Analysis (RSA) with 3 factors and 3 levels were adopted. The results show that the optimum conditions were the extraction temperature of 70℃, the ratio of material to ethanol of 1:30, the ethanol concentration of 70%. The relationship between OD and the main three factors could be described as followed:OD=1.049833-0.020525x+0.010050y-0.005650z+0.004096x~2-0.000425xy+0.024446y~2 +0.020625zx-0.002825zy-0.002854z~2。It was acetone that used to isolate dihydromyricetin from the extract. The optimum condition was attained through orthogonal array, which were the ratio of material to acetone of 1:12, isolation time of 20min and three- times extraction.After analyzing UV-Vis, IR and HPLC of the product isolated by acetone, it was shown the main component was dihydromyricetin.2. Effect of Dihydromyricetin on Lowering HyperglycemiaAlloxan-induced mice were continuously intraperitonal administrated for 12 days atthe dose of lOmg/kg.bw, 50mg/kg.bw, lOOmg/kg.bw. After last administration, the mice were fasted for at lest 10 hours, then they were sacrificed by cervical dislocation. The spleen, thymus, liver and kidney weight in the mice were measured; serum was prepared from blood obtained in eye vein cluster and serum glucose, TC, TG and HDL-C were assayed; the liver were homogenized in physiology saline and MDA, SOD and GSH-Px were assayed. The results were showed: ?Dihydromyricetin at dose of lOmg/kg.bw, 50mg/kg.bw, lOOmg/kg.bw could significantly lower the fasting serum glycose and the hyperglycemic effect of dihydromyricetin at dose of 100mg/kg.bw was the best. ? Dihydromyricetin could increase the thymus and spleen indexes in Alloxan-induced mice, which could increase the immunocompetence; decrease the liver index, which could alleviate the liver damage caused by Alloxan and had no effect on the kidney index, which showed dihydromyricetin had no side effect. ?Dihydromyricetin could decrease the content of TC and TG, while enhance the level of HDL-C of alloxan-induced diabetic mice, so it could retore the blood lipids level of diabetic mice. ?Dihydromyricetin could decrease the content of MDA and enhance the content of SOD and GSH-Px of alloxan-induced diabetic mice, so it had the beneficial effect to the oxidative stress level of diabetic mice.3. Effect of dihydromyricetin on antioxidant abilityThe antioxidant ability of dihydromyricetmr^wfro^was studied. Dihydremyricetin had scaveging effects on hydroxyle radical and superoxide anion radical; had the inhibiting effects on lipid peroxidation of liver homogenate in vitro. It also could protect liver from peroxidation induced by Fe2+ or H2O2, inhibit the mitochondria swelling and hemolysis of red blood cells, when the 0.06%of the dihydromyricetin was added to the oil and lipid, the best antioxidant ability was obtained. In different antioxidant systems, the antioxidant ability of dihydromyricetin was different.