The Extraction And Purification Of Kidney Bean Polyphenol And Its Antioxidant Effect

Polyphenol is one of the major secondary metabolites, Most of the polyphenols exist in plants, which have many physiological activities, such as anti-oxidation, anti-tumor, antibacterial, and so on. Kidney bean is widely distributed in our province, northeast is a producing region which has most species and quantity of kidney bean, which has a variety of structure and has many practical applications. With the current situation of grain production and grain staple market, the economic benefits brought by a rapid growth, nutritional value is popular, so it has a broad prospect. But the anti-nutritional factors of the seeds of beans are influnced by the toxicity of direct or indirect in beans industry development. In recent years, the research showed that the content of anti-nutrition substance was significantly decreased after germination treatment, or even disappeared. So the germination treatment could increase the nutritional value of the beans. The contents and conclusions of this paper are as follows:1. Rearch on extraction of polyphenols from kidney bean sproutsThe ethanol-solvent extraction to extract kidney bean sprouts polyphenols. Determination of crude polyphenol content of kidney beans sprouts in liquid by Folin method. With gallic acid standard curve to calculate the extraction rate of polyphenols, kidney bean sprouts polyphenols extraction process conditions were optimized by single factor and orthogonal experiments. The results showed that the optimum extraction technology of kidney bean sprouts polyphenols: the extraction temperature was 50 ℃, the extraction time was 2.0 h, the ratio of material to liquid was 1:20, the ethanol concentration was 60%. Validation experiments were carried out under this condition, the extraction rate of polyphenols in kidney bean sprouts can reach 2.76%.2. Separation and purification of kidney bean sprouts polyphenols by macroporous resinStudy on the optimum conditions of macroporous resin to pure the polyphenol from kidney beans. Five kinds of macroporous adsorption resins(HPD100, D4020, X-5, NKA-2 and AB-8) were screened by static adsorption desorption experiment and dynamic experiment. Finally, AB-8 resin was chosen as the resin. The results showed that the optimum technological condition of kidney bean sprouts polyphenols: the concentration of the sample was 1.0 mg/mL, the ethanol solution concentration was 70%, the elution flow rate was 1.0 mL/min. Under these conditions, the purification purity was improved from 10.37% to 32.29%. The method is simple in operation, low in cost and high in stability.3. Study on antioxidant activity of polyphenols of kidney bean sproutsWith ascorbic acid(Vc) as control were measured kidney beans sprouts polyphenols on DPPH, superoxide anion radical and hydroxyl radical scavenging capacity. Based on the linear equation, the IC50 value of kidney bean sprouts polyphenols crude extract, purified substances and Vc were 0.409 mg/mL, 0.285 mg/mL, 0.086 mg/mL in the DPPH radical scavenging; In the experiment of superoxide anion free radical scavenging, the IC50 value of kidney bean sprouts polyphenols crude extract, purified substances and Vc were 0.264 mg/mL, 0.183 mg/mL and 0.091 mg/mL; In the experiment of hydroxyl radical scavenging, the IC50 value of kidney bean sprouts polyphenols crude extract, purified substances and Vc were 0.263 mg/mL, 0.223 mg/mL and 0.079 mg/mL. Three kinds of the evaluation experiments showed that on the free radical scavenging ability increased with increase of kidney bean sprouts polyphenol purity, but the antioxidant activity all be weaked in Vc.4. Research on repair of oxidative damage and protective effect of liver and kidney withkidney bean sprouts polyphenols on peroxidation in miceTo the experimental mice by intraperitoneal injection D-galactose, with ascorbic acid(Vc) as control continuous irrigation stomach to kidney bean sprouts polyphenol for 28 days, determinationed for SOD, GSH-Px, MDA levels and liver and kidney functions, to observe the pathological changes of liver and kidney tissue of mice, and to record the changes in body weight of mice. The results showed that kidney bean sprouts polyphenols on mice weight, liver weight and kidney weight all had no significant effect that the toxic and the side effect was low, had certain protected and repaired effects of the immune organs of mice. Also kidney bean sprouts polyphenols can promote the indicators of oxidative damage in mice serum SOD, GSH-Px and MDA tended to be normal(P<0.05) and the effect was dose-dependent. In the repair of liver and kidney tissue, intaked of D-galactose to liver and kidney of mice significantly damage, triggering the body’s inflammation, liver and kidney function of mice model were abnormal, but no significant changed in body weight and organ coefficient. At the same time, kidney beans polyphenols increased the oxidative injury in mice serum ALT, AST, BUN and CR tended to be normal(P<0.05). So kidney baens polyphenols can repair the liver and kidney tissue, it can make the body be healthy.