Study On Separation, Purification, Coordinated Complexes And In Vitro Antioxidant Activity Of Proanthocy Anidins From Picea Koraiensis Nakai’s Cones Lamella

Proanthocyanidins are a group of polyphenols, which possessed special health care function and a wide range of efficacy and minimal side effects, were widely used in cosmetics, health products, pharmaceuticals and a variety of beverage products, possessing a high value of development. Proanthocyanidins from Picea koraiensis Nakai’s cones lamella were studied on extraction process, purification process and antioxidant capacity. Purified proanthocyanidins were chelated to Fe2+、Zn2+and complexed to bovine serum albumin after being refined through secondary purification. Proanthocyanidins polymer was prepared and the hydrolysis process was studied. The results were as follows:(1) Phenolic compounds in Picea koraiensis Nakai’s cones lamella were extracted with13kinds different extracting solvents. The antioxidant properties and contents of phenolic compounds were examined. Then the correlation between contents and antioxidant properties was investigated. The addition of water to acetone or ethanol can enhance the extracting yield and antioxidant activity. Proanthocyanidins was the major component of pine polyphenols from Picea koraiensis Nakai’s cones lamella and played an important role in the antioxidant activities.(2) Through one-factor and response surface method, the optimum conditions for the extraction of proanthocyanidins from Picea koraiensis Nakai’s cones lamella were obtained: concentration of ethanol60%, temperature of extraction51℃, extraction time2h, the ratio of material to solvent1:44(g/mL). Under these conditions, the maximum extraction yield of proanthocyanidins was (72.23±0.35)mg/g.(3) Adsorption and desorption experiments were carried out to filter out the suitable macroporous resin for purification. The optimal conditions of proanthocyanidins with D4020were as follows:elution concentration60%, sample concentration2.5mg/mL, diameter and height ratio1:25, eluting speed2.5mL/min. The max sample volume was40mL. The max elution volume was200mL. The value of purity of crude proanthocyanidins extracts was (29.45±1.33)%. Under these conditions, the value of purity of purified proanthocyanidins was (60.57±1.78)%. The recovery rate was (88.27±3.18)%. The results showed that the purified proanthocyanidins possessed relatively strong reducing power and capacity of scavenging free radicals. The reducing power was stronger than the positive control Trolox.(4) The optimal conditions of proanthocyanidins with NKA-9were as follows:elution concentration60%, sample concentration3.0mg/mL, diameter and height ratio1:25, elution pH=7. The max sample volume was40mL. The max elution volume was200mL. The coordination characteristics of proanthocyanidins showed that:The conditions optimized for proanthocyanidins chelating to Fe2+were:the proanthocyanidins concentration8mg/mL, the temperature30℃, the pH=6. The conditions optimized for proanthocyanidins chelating to Zn2+were:the proanthocyanidins concentration5mg/mL, the temperature20℃, the pH=4. The conditions optimized for proanthocyanidins complexing to bovine serum albumin were:the proanthocyanidins concentration3mg/mL, the temperature40℃, the pH=6. The antioxidant activity of proanthocyanidins increased after coordinated. The activity of scavenging free radicals and reducing power were enhanced at a certain degree.(5) The hydrolysis process of proanthocyanidins polymer from Picea koraiensis Nakai’s cones lamella was studied. The result showed that hydrolysis took place at60℃for30min with H2SO3as hydrolysis medium and the sample volume0.8ml. Under these conditions, the average degree of polymerization of proanthocyanidins polymer dropped to1.03from4.15and the activity of scavenging DPPH· was enhanced significantly.