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Isolation and purification of two antioxidant isomers of resveratrol dimer from the wine grape by counter‐current chromatography
Author(s) -
Kong Qingjun,
Ren Xueyan,
Hu Ruilin,
Yin Xuefeng,
Jiang Guoshan,
Pan Yuanjiang
Publication year - 2016
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201600004
Subject(s) - chemistry , dpph , wine , flavonols , chromatography , polyphenol , proanthocyanidin , ethyl acetate , column chromatography , dimer , resveratrol , antioxidant , organic chemistry , food science , biochemistry
Resveratrol dimers belong to a group of compounds called stilbenes, which along with proanthocyanidins, anthocyanins, catechins, and flavonols are natural phenolic compounds found in grapes and red wine. Stilbenes have a variety of structural isomers, all of which exhibit various biological properties. Counter‐current chromatography with a two‐phase solvent system composed of n ‐hexane/ethyl acetate/methanol/water (2:5:4:5, v/v/v/v) was applied to isolate and purify stilbene from the stems of wine grape. Two isomers of resveratrol dimers trans‐ε ‐viniferin and trans ‐δ‐viniferin were obtained from the crude sample in a one‐step separation, with purities of 93.2 and 97.5%, respectively, as determined by high‐performance liquid chromatography. The structures of these two compounds were identified by 1 H and 13 C NMR spectroscopy. In addition, their antioxidant activities were assessed by 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assay. The antioxidant activities of trans ‐δ‐viniferin were higher than that of trans‐ε ‐viniferin in this model. This work demonstrated that counter‐current chromatography is a powerful and effective method for the isolation and purification of polyphenols from wine grape. Additionally, the DPPH radical assay showed that the isolated component trans ‐δ‐viniferin exhibited stronger antioxidant activities than trans‐ε ‐viniferin and a little bit weaker than vitamin E at the same concentration.