Isolation And Purification Of Stilbenoids From The Xinjiang Wine Grape And Determined Their Antioxidant Activity

Object:Wine grapes are rich in a variety of biological active ingredients,such as stilbenoids,flavonoids and terpenoids,etc.,and are a good source of natural antioxidants.In this study,the grape stems from one of the Xinjiang grape wine industry wastes were used as experimental materials.We used many method to separation of active substances from grape stems and determination their antioxidant activity,the aim is to obtain some good active compounds and provide a theoretical basis for plant derived natural antioxidants to replace synthetic antioxidants,development of new food additives,improve the utilization rate of the grape stems and the realization of turning waste into treasure.Methods:Using the traditional organic solvent extraction method to separation the active substances in grape stems,combination of normal phase silica gel,Sephadex LH-20 gel,high performance liquid chromatography for purification of compounds.The structure of compounds were determined by the way of mass spectrometry,nuclear magnetic resonance analysis and material specific rotation.Three methods of in vitro chemical oxidation(DPPH free radical scavenging activity,ABTS radical scavenging and reducing power assay)and cellular antioxidant activity(CAA)method to comprehensive evaluated the antioxidant activity of five stilbenoids.Finally,the effects of five stilbenoids on the expression of 6 kinds of apoptosis related genes and 3 genes related to oxidative stress in ABAP damaged cells were determined by real-time fluorescence quantitative PCR.Results:Five stilbenoids were identified: a pair of isomers of resveratrol dimers Trans-?-viniferin,(+)-Cis-?-Viniferin,resveratrol tetramer(-)-Hopeaphenol;a pair of isomers of Astilbin and Isoastilbin.Three kinds of chemical antioxidant experiments in vitro showed that all the 5 kinds of stilbene compounds had certain antioxidant effect.In a certain concentration range(10 ?g/mL-200 ?g/mL),the antioxidant effect was enhanced with the increase of concentration.Among the 5 compounds,compound Astilbin had the strongest antioxidant activity,while the chemical antioxidant activity of(+)-Cis-?-Viniferin was the weakest.The experimental results of CAA showed that there were significant differences in the antioxidant effects of the 5 compounds.The strongest antioxidant activity of cells was Astilbin,while Isoastilbin had the worst antioxidant effect.The results of fluorescence quantitative PCR test showed that,except(+)-Cis-?-Viniferin,the other four stilbenoids all had a good scavenging effect on reactive oxygen species generated by ABAP,which could effectively reduce the occurrence of apoptosis.Conclusion:The results showed that the stem of Xinjiang wine grape is one of the sources of stilbenoids,it can separate stilbenoids with antioxidant activity.It is found that the compound Astilbin has strong antioxidant activity,and its activity should be further explored in the future.