Quantification of polyphenol composition and multiple statistical analyses of biological activity in Portuguese red wines

The objective of the research was to evaluate potential biological activities of Portuguese red wines with different grape types on the level of composition characterization. An ultrafast liquid chromatography coupled with triple quadrupole mass spectrometry method was validated and used for qualitative analysis of commercial red wine samples through simultaneously determining 31 major active components. Meanwhile, the antioxidant activities of red wines were measured by DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)] and CUPRAC (cupric ion reducing antioxidant capacity) assay. The relations between polyphenols and antioxidant values were further considered by multivariate statistical analysis. Results of correlation analysis and stepwise multiple regression analysis showed that antioxidant activities were highly correlated to polyphenolic profiles, with significant contributions of procyanidins and phenolic acids. Consequently, the assessment method we established appeared to be an effective tool for appraising the nutritional value of polyphenols in wines, and the research strategy could be applied to the evaluation of other beverages.