Study On The Aqueous Two Phase Extraction Of Purple Sweet Potato Anthocyanins And Its Protective Effect On Alcohol Liver Disease

Purple sweet potatoes are rich in anthocyanin. Many studies suggest that anthocyanin exhibitsmultiple physiological functions including anti-oxidation, memory enhancing and hepato-protection. Inthis study, purple sweet potato anthocyanins（PSPAs）were extracted using aqueous two-phase system,and the conditions were optimized; Under the optimum conditions, the degradation kinetics, the effectson the acute and sub-acute alcohol liver disease were studied. The aim of this research is to increase theadditional value of purple sweet potato, and provide theoretic support for the development of functionalfoods with antioxidant and hepato-protective activities.The response surface methodology was employed to study the extraction of anthocyanins frompurple sweet potato. On the basis of single-factor experiments, the effects of ethanol concentration,ammonium sulphate concentration, liquid-solid ratio, deionized water pH value （pH） on the recovery（Y1） and the partition coefficient （Y2） were studied using Box-benken design. The results showedthat the optimal technological parameters for the aqueous two-phase extraction （ATPE） of PSPAswere as follows: liquid-solid ratio of45:1（mL/g）, ethanol concentration of27%（w/w）, ammoniumsulphate concentration of20%（w/w）, pH3.4. Under such extraction condition, Y1and Y2were90.0183%and19.6163respectively. There is no significant difference between actual values andpredictive values （P＞0.05）, and the models can be used in the prediction of actual extraction process.HPLC-ESI-MS/MS analysis results showed that the PSPAs were mainly composed of peonidins andcyanidins acidylated by caffeic acid, fumaric acid and hydroxy benzoic acid.The effects of PSPAs against acute alcohol induced liver disease on C57BL/6J mice wereinvestigated. The results showed that PSPAs was able to anti-alcoholism. Administration of PSPAs priorto alcohol prevented the increases in serum aspartate transaminase（AST）, alanine transaminase（ALT）,lactate dehydrogenase （LDH）, hepatic triglyceride（TG）, total cholesterol（TCH）, andmalondialdehyde （MDA） levels. The activities of superoxide dismutase （SOD） andglutathione-s-transferase（GST）were improved by PSPAs. Compared to the alcohol group, the hepaticswelling was inhibited by PSPAs through histopathological studies. These results suggest that PSPAshave some protective effects on acute alcohol liver disease.The effect of PSPAs on the liver of sub-acuted alcohol-treated C57BL/6J mice was studied.Compared to alcohol group, the following was observed: significant decrease in the activity of serumAST、ALT、LDH and hepatic ADH（P<0.05）and decrease the content of MDA, and increase in theactivity of hepatic SOD and GST, the liver disease was improved by PSPAs through histopathologicalstudies. In conclusion, our data suggest that PSPAs is a good antioxidant, decreases the level ofoxidative stress and lipid peroxidation, and exerts a protective effect in serum and in liver of miceintoxicated with ethanol.The degradation kinetics of PSPAs in different storage solvents（0%ethanol,10%ethanol,20%ethanol,50%ethanol）were studied through classical isothermal kinetic method. The results indicatedthat the thermal degradation of PSPAs followed the first-order reaction kinetics. Based on an Arrhenius-type and Eyring-Polanyi model, the experimental data showed reaction activation energy（Ea） values were found to be83.46,78.53,78.09,75.33kJ/mol kJ/mol at0,10,20and50%ethanolconcentrations, enthalpy （Δ H） values were77.33,72.41,71.97,69.21kJ/mol/K, entropy （Δ S）values were180.81,188.37,189.94,193.57J/mol/K, respectively.