ABSTRACT
The content of the stilbenes trans-resveratrol and piceid as well as the antioxidant activity of Macedonian red wines from the two main grape varieties Vranec and Merlot have been evaluated. Тhe effects of time of maceration, type of yeast and the level of sulphur dioxide applied on stilbene content and antioxidant activity have been studied. The most important factor in winemaking technology is the maceration time since the highest concentrations of trans-resveratrol, piceid and highest antioxidant activity were found following 6 and 10 days of maceration. Concerning the yeast type, higher concentrations of trans-resveratrol and piceid have been obtained with French yeast "Levuline CHP" in comparison to Macedonian yeast "Vinalco". In contrast, the higher antioxidant activity of wines from both varieties of grapes was observed by application of Macedonian yeast "Vinalco".
Subject(s)
Antioxidants/analysis , Stilbenes/analysis , Wine/analysis , Antioxidants/metabolism , Industrial Microbiology/methods , Resveratrol , Stilbenes/metabolism , Vitis/chemistry , Vitis/microbiology , Wine/economics , Wine/microbiology , Yeasts/metabolismABSTRACT
Health benefits of trans-resveratrol and other stilbenes in grapes, must, and wine have been pointed out by numerous authors. Less attention has been paid to the presence of stilbene derivatives in viticultural residues, such as grape canes. The present work reports the first results of a systematic study of stilbene levels in different grape varieties and cultivation areas in Chile, to evaluate their potential as an alternative source of bioactive stilbenes. In all cane samples, the predominant stilbene is trans-resveratrol, followed by ε-viniferin and piceatannol. In canes of Pinot noir up to 5590 ± 172 mg kg(-1) of trans-resveratrol and up to 6915 ± 175 mg kg(-1) of total stilbenes were detected. The observed concentrations of stilbenes in canes of Pinot noir from southern Chile until now are higher than those reported previously for this red variety. However, the highest concentration of total stilbenes observed in the analyzed samples was in the canes of white variety Gewürztraminer with 7857 ± 498 mg kg(-1). Preliminary results indicate that these levels can evolve if canes are left for some months on the vineyard after pruning, observing an increase during the first 2 months and a decrease after this period.
Subject(s)
Chromatography, High Pressure Liquid/methods , Stilbenes/analysis , Tandem Mass Spectrometry/methods , Vitis/chemistry , Chile , Plant Stems/chemistry , Species SpecificityABSTRACT
Two stilbenes, trans-resveratrol and (-)-epsilon-viniferin, as well as a mixture of both, were biotransformed using horseradish peroxidase and hydrogen peroxide. Under the applied conditions trans-resveratrol afforded one major product, which was identified as trans-delta-viniferin, a resveratrol-trans-dehydrodimer. Large-scale biotransformation of a mixture of trans-resveratrol and (-)-epsilon-viniferin yielded two novel resveratrol trimers, resviniferin A and resviniferin B, which were obtained in a pure form after fractionation by high-speed countercurrent chromatography and final purification by preparative HPLC. Their structures were established by means of mass spectrometry and 2D NMR spectroscopic analyses, including HSQC, HMBC, COSY, and ROESY.
Subject(s)
Benzofurans/chemistry , Horseradish Peroxidase/chemistry , Resorcinols/chemistry , Stilbenes/chemistry , Catalysis , Molecular Structure , ResveratrolABSTRACT
The health promoting effects of a grapevine-shoot extract named Vineatrol30, which contains resveratrol (Resv) as well as considerable amounts of Resv oligomers, have recently been investigated. In the present study, we analyzed the free radical scavenging capacity, the ability to inhibit lipid peroxidation, and the capacity to enhance the human glutathione peroxidase 1 (GPx) and the human superoxide dismutase 1 (SOD) gene promoter activities of Vineatrol30. Vineatrol30 was able to scavenge the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical cation and led to concentration-dependent inhibition of lipid peroxidation, Vineatrol30 not being superior to Resv alone in both cases. Vineatrol30 also enhanced the gene promoter activities of human GPx and SOD expressed in V79 cells, whereas this effect could not be demonstrated for Resv. In summary, the results presented in this study show that the Vineatrol30 grapevine-shoot extract is a free radical scavenger and potent antioxidant at non-cytotoxic concentrations.
