Separation, Analysis, Characteristics And Application Of Polyphenols From Chinese Bayberry

Chinese bayberry(Myrica.Rubra Sieb.et Zucc.) is a specific fruit species in China.There are plenty of anthocyanins and flavonoids in it.In this paper,the extraction,isolation,purification and antioxidant activity of anthocyanins and flavonoids in bayberry were studied,and the structure and stability of anthocyanins were also researched.The results were as follows:1.Determination of the optimal extraction condition of anthocyanins and flavonoids in bayberryThe optimal extraction condition of anthocyanins and flavonoids in bayberry was established.When the material was extracted with 70%ethanol(pH3) at 40℃and at the ratio of liquid to material(v/w) 11:1,the extraction rate of anthocyanins and flavonoids was 94.33%and 93.72%respectively.2.Isolation and purification of anthocyanins and flavonoids from bayberryThe separation effects of three macro-porous resins(AB-8,D101 and ADS-17) on anthocyanins and flavonoids from bayberry were studied.It is found that the separation effects of AB-8 and D101 were better.The optimal conditions of these two resins both were:the extraction concentration of bayberry was adjusted to pH 3.0 and applied to AB-8 and D101 macro-porous resin,eluted with distilled water and 60% ethanol at the natural flow rate and 60%ethanol elution was collected,concentrated and freeze-dried to give extracted powder.The product yield was 1.44%and the contents of anthocyanins and flavonoids were 22.08%and 70.758%respectively.Sephadex LH-20 was used to further separate anthocyanins and flavonoids from bayberry extract.The bayberry extract with resins was applied to a Sephadex LH-20 column.The column was eluted with 20%methanol(contain 0.1%HCl) and 60% acetone solution successively,the main chromatography peaks with 20%methanol as eluting solution was collected to give product 1,and 60%acetone eluting solution was collected to give product 2.The yield of product 1 was 29.49%,its anthocyanins content was 73.88%;the yield of product 2 was 46.08%,its flavonoids content was 85.31%.3.Structure identification of anthocyanins from bayberryThe anthocyanins in product 1 were identified by the UV-vis,IR,and HPLC-MS. The results showed that cyanidin-3-glucoside and peonidin-3-glucoside were the main anthocyanins of bayberry,and the cyanidin-3-glucoside content was more.4.The stability of anthocyanins in bayberryThe stability of bayberry anthocyanins under different conditions were studied. The effect of sugar on the stability of anthocyanins was related to the structure and concentration of sugar.When the sugar concentration was low(＜5%),sucrose, glucose and fructose all could protect the color of anthocyanins from bayberry,and sucrose is best.With increase the concentration,the protective effects of sucrose and glucose on anthocyanins were stabilities whereas fructose accelerated the degradation of anthocyanins,the preservative rate of anthocyanins was merely 53.49%when the fructose concentration was 20%.Tea polyphenols and rutin could protect color and have a adjuvant function.Anthocyanins were stable at low pH(pH≤4),but degradated strongly when pH＞4.The preservative rate of anthocyanins decreased gradually with the increase of temperature,the thermal degradation of anthocyanins according to the first order kinetic reaction with half-life(t_1/2) 133.8247min and degradation constant(k) 0.005262.The heating time has an obvious effect on the Hunter a value of the anthocyannins solution,the hunter a value was decreased with the heating time increase.Fe³⁺,Fe²⁺ and Al³⁺ could complex with anthocyannins and change color of anthocyanins,but Ca²⁺,Cu²⁺,Na⁺,K⁺ did not had any effects on anthocyannins color.Anthocyanins were sensible to light,and hydrogen peroxide and ascorbic acid could accelerate the degradation of anthocyanins remarkably.Bovine serum albumin(BSA) could complex with anthocyanins to form polymer and had some protection effect.In the fermentation process of bayberry wine,300 mg/L rutin or tea polyphenols had some protection effect on wine color.5.Antioxidant effects of polyphenols extract from bayberryDifferent systems were used to study the anti-oxidative activity of different bayberry's extracts.The results showed that sample 1(phenolic extract),sample 2 (anthocyanins fraction),sample 3(flavonoids fraction) and sample 4(the powder of bayberry juice) were all effective antioxidants.They all showed high anti-oxidative activities in these four systems.Sample 1 had the best anti-oxidative activity,its scavenging activities on superoxide anion,hydroxyl radical and DPPH were higher than that of EGCG and Vc,but its scavenging effect on H₂O₂ was lower than EGCG. The scavenging activity on DPPH of sample 2(anthocyanins fraction ) was stronger than sample 3(flavonoids fraction),but its scavenging activities on superoxide anion, hydroxyl radical and H₂O₂ were lower than that of sample 3(flavonoids fraction).The results hinted that anthocyanins and flavonoids from bayberry both had high anti-oxidative activities,and these two compounds also had synergistic effect.