| None-natural and chemical resourse antioxidants are commercial and wide used in morden food production, to make foods less lipid oxidation. Meanwhile synthetic antioxdants are well-known for their potential health risks, for this reason, they are under stem regulations in food industry. With the development of natural-resourses plant antioxdants is regarded as a effective and good alternatives for the food oxidant deterioration. The result of the research of active component in the seabuckthorn leaves shows the flavonoid of the seabuckthorn leaves is a promising resourse to yielding natural antioxidants. The fuction of the seabuchthorn leaves flavonoid has the capability to savenge free radicals, inhibiting liver damage and improving intestinal immune ability. The objectives of this research were to prepare Seabuckthorn leaves extract with high flavonoid content and antioxidant activity. The optimal extraction condition of total flavonoids of Seabuckthorn leaves, using ethanol-hydrochloric acid solution assisted by ultrasonic was determined, as well as main component analysis using HPLC and antioxidant stability. The antioxidant effects of Seabuckthorn leaves extract in raw and cooked pork patties were evaluated. In addition,it do good to alleviate the damaged of human embryonic lung fibroblast cells MRC-5attacked by H2O2, hepatoprotective effect on Gal-N-induced liver damage in rats and the influence of the intestinal mucosal immunity in mice were also investigated. The main results were as follows:1. The optimum conditions for extracting total flavonoids from the Seabuckthorn leaves were found to be:ethanol concentration50%, material-to-liquid ratio1:20(g/mL), hydrochloric acid concentration3mol/L, extraction time30min and ultrasonic power80W. Under these optimum conditions, the total yield of flavonoid reached as high as6.34%, and the total flavonoids extract possessed marked antioxidant activities. This study opens a new route for the extraction of total flavonoids from the Seabuckthorn leaves.2.20mg/kg Seabuckthorn leaves extract has higher reducing power, in comparison to0.1mg/kg BHA and0.1mg/kg ascorbic acid, as same as ABTS+and superoxide radicals scavenging activity shows nice result (P<0.05), but less abilty to BHA in DPPH and hydroxyl radical scavenging activity (P<0.05).3. The main components of Seabuckthorn leaves extract was analysed using high performance liquid chromatograph (HPLC). The four components were rutin, myricetin, quercetin and isorhamnetin. The total content of each of them was30.32,20.05,29.01and23.08mg/g, respectively.4. The different pH value, avoid light preservation, metal ions and heating conditions on the antioxidant activities of Seabuckthorn leaves extract (reducing power and ABTS radical scavenging activity) effect was not significant (P>0.05), but in the sunlight and fluorescent light, its antioxidant activity decreased significantly (P<0.05). In addition, this research provided theoretical basis of Seabuckthorn leaves extract for application in food industry as natural antioxidants.5. The Seabuckthorn leaves extract at a0.02%,0.05%,0.10%and0.20%addition of meat patties (weight/weight). During7days of storage, red color index, pH, carbonyl groups content and TBARS experiment was measured and organized a sensory evaluation experiment to judge the quality of raw pork patties. The results showed that the treatments of the seabuckthorn extract had significant inhibitory effects on lipid oxidation and kept the a*-value of patties in7days, in comparison to the controls, and shows the obviously dose effect ration, be equivalent to BHA, sensory evaluation has the same result.6. Seabuckthorn leaves extract at a0.02%,0.05%,0.10%and0.20%concentration level(w/w) were added to fried meat patties, during the storage period, red color index, pH, carbonyl groups content and TBARS+value were measured and organized a sensory evaluation experiment to appraise the quality of fried meat patties.. The results shows the addition of Seabuckthorn leaves extract had obviously inhibitory effects on free radical reaction induced lipid oxidation, equivalent to BHA, sensory evaluation has the same result.7. The Seabuckthorn leaves extract could protect the MRC-5in alleviating the degree of H2O2induced cytotoxicity. The extract treated cells had higher cell viability than the control. Additionally, the cytoprotective effect of Seabuckthorn leaves extract was in conneted with the decline in the MDA level and increases in cell enzyme of the SOD, CAT and GSH-Px activities in treated MRC-5cells.8. The Seabuckthorn leaves extract processed significant hepatoprotective effect on Gal-N-induced liver damage in rats. First of all, Seabuckthorn leaves extract could significant reduced the ALT and AST level of serum of the rat (P<0.05), indicated that it has good hepatoprotective effect, and were benefit to health. Secondly, compared with negative control group, SOD, CAT and GSH-Px activities and T-AOC of liver of the rats were increased significantly (P<0.05) and the MDA content of liver of the rats was sharply decreased (P<0.05) treated by all dose of Seabuckthorn leaves extract. Our study showed that the Seabuckthorn leaves extract could obviously reduce the liver damage which induced by Gal-N.9. Medium dose of Seabuckthom leaves extract could promote the intestinal mucosal immunity in mice. Secretory immunoglobulin A (SIgA), interleukin2(IL-2) and interleukin4(IL-4) levels were significant increased (P<0.05), which promoted continuous body intestinal T cell differentiation, as well as the body's immune level was improved. At the same time, from the content of interferon ? (IFN-?) and the ratio of IFN-y and IL-4, the medium dose of Seabuckthorn leaves extract could promote intestinal mucosal immunity levels, and enhance humoral immunity and cellular immunity ability is normal, to resist outside eyewinker infection to ensure the body most good intestinal health.In addition, high dose group caused the intestinal cellular immunity was inhibited, the body is not sensitive to outside eyewinker, bad for the body intestinal health. |
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