| There was few reports selecting anthocyanins of purple yam(APY)as an experimental material so far.Development based on APY asnutritional factors for functional food has a broad market prospect,which can bring great social and economic benefits.APY,having the potential application value as drug factors and nutritional factors in pharmaceuticals,food and other fields,contains various bioactive substances.The extraction,purification of APY and its hypoglycemic and antioxidant functions were studied in the research.The results were shown as follows:Using the extraction method of ASE to extract APY,the best extraction process for APY was determined by response surface optimization parameter method.The best process was that:the extraction temperature is 111.8℃,the extraction time is 9.72min,the ethanol concentration is 67.9%,the liquid-solid ratio is 7.3:1.The predictive extraction rate of APY is 13.53 mg/100g at the best process.The average extraction rate of APY is 13.88 mg/100g after updating the best process.And the error is 2.5%compared to theoreticalprediction,which explainsa good match between the experimental results and the model.It also shows 13.88 mg/100g is the highest extraction rate at experimental process.The model of response surface is proved to be feasible and of practical value.The experiment used six macroporous resins that wereadopted the use of wet packed column.The optimal conditions of purifying purple yam pigments was determined by selecting the stationary phase media and optimizing mobile phase media.The AB-8 resin has a better ability to adsorb and desorb APY,with pH 3.0,60%ethanol solution as the desorption solution,dynamic adsorption and desorption conditions were as follows:flow rate of absorption is 1.5mL/min,Sample concentration is3mg/mL,the flow rate of elution is 1mL/min with 60%acidic ethanol as eluent;the AB-8 resin has better reusable performance,the adsorption rate decreased only 3.05%after six-time repeation.With the purification of the AB-8 resin,APY became purple black powder and had a purity of 42.8%,which increased 31.8%than before.Under optimal elution conditions,the APY were divided into three groups of APYⅡ.APYⅢ、APYⅣ according to anthocyanin content and total antioxidant capacity.The factors that may impact the stability of APY such as pH,temperature,metal ions,light,oxidizing and reducing agents were taken into account.The conclusions:APY was stable in acid conditions,while in neutral to slightly alkaline conditions,it was very unstable ad degradation occurred;heat and light had some damaging effects on anthocyanins,the temperature of over 60℃and direct light would distinctly decrease the pigment stability;Mg2+and Ca2+played a hyperchromic and stabilizing role;Al3+、Mn2+、Fe2+、Zn2+had weak influence on the pigment stability;Fe2+、Fe3+and Cu2+had hypochromic effect on pigment,so it should avoid contacting with the copper and iron metal utensils in production and practical applications.Purple yam pigment were more sensitive to H2O2 and Na2SO3,which should avoid being used.Total antioxidant capacity of purple yam pigment were detected,as well as scavenging activity of hydroxyl radicals,superoxide anion,rPPH,ABTS+ and other free radicals.The conclusions:The group APYⅢ has a great total antioxidant capacity and great ability to scavenge O2-·、OH·、DPPH·and ABTS+,all better than Vc.The group APYII has free radical scavenging ability than Vc except the ability to scavenge ABTS+、DPPH·.The group APYIV has similar·OH scavenging ability with Vc,the rest scavenging ability worse than Vc.The purified groups of APYⅡ、APYⅢ、APYⅣ could reduce mice’water intake and food intake,meanwhile increasing its body mass.It could inhibit blood glucose of diabetic mice and BUN in serum.It could increase insulin,maltase level,liver glycogen and muscle glycogen level in diabetic mice,and its regulating ability is related to dose.The regulating ability:APYⅢ(the highest total antioxidant activity)>APYⅡ(the lower total antioxidant activity)>APYIV(the lowest total antioxidant activity).It proved that APY could be expected as a good hypoglycemic drug owing to the ability of some components to effectively control the symptoms of diabetes.Three tumor cells(human colon cancer cell line COLO-320;human breast cancer cell line SK-BR-3;human hepatoma cell line QGY-7701)were selected by MTT method to get the cells with a good inhibitory effect to be cultured.Apoptosis of tumor cells affected by APYwasdetected.The conclusions:APY could inhibit tumor cell QGY-7701,IC50 value of SK-BR-3 was 43.73μg/mL、145.30μg/mL.APYⅢ selected by MTT method had a best inhibitory effect on Human hepatoma cell QGY-7701,the inhibition rate of tumor cell could reach to 82.36%with 200μg/mL APY for 72h.The composition of anthocyanins from APY was detected by HPLC-DAD-MS.The main anthocyanin in the APY was peonidin-3-O-glucoside-5-O-glucoside,cyanidin-3-O-Coumaric acid glucoside-5-O-glucoside,peonidin-3-O-glucoside-5-O-glucoside,Acetyl anthocyanins.Correlations antioxidant activity of anthocyanins from purple yam with hypoglycemic effect and Inhibition of tumor.Results:There was correlation between the hypoglycemic effect and scavenging ratio DPPH·,ABTS+-,O2-·and total antioxidant capability.The inhibition rate of cancer cells:colon cancer cells<breast cancer cells<liver cancer cells.There was correlation between the Inhibition of tumor and scavenging ratio O2-·and total antioxidant capability. |
