Study On Extraction And Purification Of Tartay Buckwheat Leaves Flavonoids And Its Hypolipidemic Activity

Ftataricum, a polygonaceae dicotyledonous plant, is rich in biological flavonoids, rutin, sugar alcohol and other active ingredients. Studies have shown that flavonoids have hypolipidemic, hypoglycemic, antioxidant and anticancer activities, which is one of the focuses in food and drugs field. In this study, the optimum extraction and purifition conditions of flavonoids from tartay buckwheat leaves were explored and the effects of tartay buckwheat leaves and its alcohol extract on blood lipid level in hyperlipemia hamsters were also investigated in order to take full advantages of flavonoids from buckwheat.The flavonoids contents in different growth days tartay buckwheat leaves were detected by using spectrophotometric method. The results showed that the highest flavonoid content was observed up to 10.74% in the tartay buckwheat leaves which were grew for 55 days to 75 days.High performance liquid chromatography (HPLC) method were employed to analyzed the flavonoids monomer composition in tartay buckwheat leaves alcohol extract with C18 column under 360 nm. A binary H2O-0.4% phosphoric acid (solvent A) and acetonitrile (solvent B) gradients was used for elution. It was showed that alcohol extract from tartay buckwheat leaves mainly contains three flavonoids including rutin, quercetin and rhizoma kaempferiae phenol and the content of rutin is highest among them.Optimization of extraction condition of alcohol extract flavonoids from tartay buckwheat leaves was investigated through single factor experiments and the response surface methodology. The optimal conditions were determined as follows:extracting temperature was 70℃, the liquid-solid ratio was 25:1, extracting time was 3 hours by using 60% ethanol. The crude extract yield was 44.74% and the purity of flavonoids was 24.03%.The D101 resin were selected for it has betterpurification efficiency than others we usually used, he optimal conditions of tartay buckwheat leaves flavonoids were determined as follows:Wet packing column at room temperature, etting D/H ratio of chromatography at 1:17, adding 2 BV of sample solution, keeping elute speed at 4 mL/min, the sample concentration is 0.86 mg/mL,then use 4 BV 75% ethanol solution for elution. The purity of flavonoids in purification product was 52.15%.Male hamsters were randomly divided into five groups (n=8):normal group, model group, low-dose and high-dose groups of tartay buckwheat leaves alcohol extracts and tartay buckwheat leaves group. Hyperlipidemia indicators in serum and liver tissues were tested after feeding 6 weeks.Compared with the model group, the total cholesterol (TC) and triglyceride concentrations (TG), atherogenic index of serum and liver were significantly decreased by feeding the tartay buckwheat leaves and alcohol extracts; the concentration of high density lipoprotein cholesterol in serum exhibited a significantly increase. Meanwhile, the content of MDA was decreased markedly in serum and liver.The liver slices of hamsters were observed by HE staining, it is showed that tartay buckwheat leaves alcohol extracts and tartay buckwheat leaves could improve the pathological symptoms effectively.The results suggested that the tartay buckwheat leaves and alcohol extracts possessed hypolipidemic activity.