| Extraction and purification of flavonoids from Hippophaerhamnoides L. residues and its hypoglycemic activityQun-hua CaoSupervisor: Professor Wei-jing Qu Major: Botany Subject: PhytochemistryResidues of seed and fruit from Hippophae rhamnoides L. were rubbishes of primary manufacture in the industry, it contains flavonoids, a bioactivity ingredient. The depth exploiture for resource of seabuckthorn, a technique of extraction and separation of effective component has been investigated in this paper by natural product chemistry. Thenceforth, to explore the function of the flavonoids by this technics in pharmacology and physiology were made by different levels from test in vitro to animal model, especially, hyperglycemic effect and its mechanism.Flavonoids from seed and fruit residues of Hippophae rhamnoides L. were analysed with UV-Vis spectra, high performance liquid chromatography and high performance capillary electrophoresis. The separation of favonoids from seed and fruit residues of Hippophae rhamnoides L was satisfied. There were rutin, myricetin, quercetin, kaempferol, isorhamnetin, catechin, epicatechin, etc in seed residues of Hippophae rhamnoides L, and there were rutin, myricetin, quercetin, kaempferol, isorhamnetin, epicatechin,etc in fruit residues of Hippophae rhamnoides L.The effects of temperature, times, hours, volume of solvent on the extraction of total flavonoids from seed residues of Hippophae rhamnoides L. were studied with orthogonal designed experiments. The results showed that the optimum conditions were 80℃, 4 times, 2 hours, 70% ethanol -herb ratio of volume to mass was 6:1 respectively.In order to get comparatively purer total flavonoids from seed residues of Hippophae rhamnoides L, two methods were compared considering the yield and purity as indexes. The results showed that purification with macroporous resinabsorbent was better. Adsorption capacity of three resins for total flavonoids was compared in the experiment. The D101 resin was the best of the three resins and its absorption capacity was determined to be 63.00mg/ g wet resin. The optimum process conditions were 30% ethanol as eluting solvent, wet resin-crude herbs ratio of mass: 2:1, diameter-height ratio: 1:10, volume of eluting solvent - mass of crude herbs ratio (V/M): 10:1, absorbing time for 3 h. The yield of total flavonoids from seed residues of Hippophae rhamnoides L. by this process was 2.39%, and the purity could reached 64.81%.The bioactivity of flavonoids from seed residues of Hippophae rhamnoides L. (FSH) and flavonoids from fruit residues of Hippophae rhamnoides L.(FFH) was studied in vitro. The results showed that FSH and FFH dose-dependently inhibited MDA generation in homogenates spontaneously and induced by H2O2, and erythrocytes hemolysis. They could also significantly scavenge NO, but slightly inhibited O2- generated by pyrogallol. FSH and FFH had evident inhibitory effect on nonenzymatic glycation induced by glucose, fructose and glyoxal incubated with albumin, but slightly inhibitory effect on a-glucosidase activity in small intestine.FSH and FFH could improve the metabolism of glucose, cholesterol and triglyceridein normal mice. FSH and FFH also could inhibit the gluconeogensis caused by L-a-Alanine and enhance anti-oxidation in normal mice.Alloxan-induced diabetic mice were administered orally with FSH and FFH at doses of 50, 100, 150 mg./kg*d-1, while distilled water and phenformin at 100 mg./kg*d-1 were given to the diabetic control group and positive control group. The results showed that oral administration of 150 mg./kg*d-1 FSH to alloxan diabetic mice exhibited significant reduction in the blood glucose levels at different time periods: 45.06% at 6th d, 46.34% at 12th d, 61.16% at 18th d, and oral administration of 150 mg./kg*d-1 FFH also caused remarkable reduction in the blood glucose levels at different time periods: 24.78% at 6th d, 32.85% at 12th d, 44.37% at 18th d. FSH and FFH could improve insulin sensitivity index (ISI) and meliorate insulin resistance. The body weight...
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