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Wine and by-products of the winemaking process, such as grape stems, are rich in bioactive polyphenolic compounds that might be beneficial for animal and human health. In recent years, the administration of dietary polyphenols with strong antioxidant and cytoprotective properties has constituted an emerging line of research interest toward disease prevention. However, in scientific literature, only a limited number of studies have investigated the safety and the toxicological risks of polyphenolic compounds in vivo. Based on the above, the purpose of the present study was two-fold: first, to examine the effects of oral administration of a grape stem extract, derived from the Greek red wine Mavrodaphne, on mice redox biomarkers; and second, to investigate the biological effects of oral administration of a wine extract, derived from the emblematic Greek red wine Xinomavro, on rats. Toward this purpose, body weight, growth rate, hematological, biochemical, and histopathological parameters, as well as a panel of redox biomarkers, were examined. According to our results, the administration of Mavrodaphne grape stem extract in mice induced alterations in redox homeostasis, preventing mice from the adverse effects of lipid peroxidation. Contrariwise, the administration of Xinomavro wine extract induced both beneficial and harmful outcomes on rat redox status determined by the examined tissue. Collectively, our study reports that the Mavrodaphne grape stem extract, a serious pollutant when disposed in environmental matrices, is an important source of bioactive polyphenolic compounds that could protect from oxidative damage and improve animal and human health. Finally, the Xinomavro wine extract exerts tissue-specific changes in redox balance, which are indicative of the complexity that characterizes the biological systems. [ABSTRACT FROM AUTHOR]

Cellular adaptive mechanisms emerging after exposure to low levels of toxic agents or stressful stimuli comprise an important biological feature that has gained considerable scientific interest. Investigations of low-dose exposures to diverse chemical compounds signify the non-linear mode of action in the exposed cell or organism at such dose levels in contrast to the classic detrimental effects induced at higher ones, a phenomenon usually referred to as hormesis. The resulting phenotype is a beneficial effect that tests our physiology within the limits of our homeostatic adaptations. Therefore, doses below the region of adverse responses are of particular interest and are specified as the hormetic gain zone. The manifestation of redox adaptations aiming to prevent from disturbances of redox homeostasis represent an area of particular interest in hormetic responses, observed after exposure not only to stressors but also to compounds of natural origin, such as phytochemicals. Findings from previous studies on several agents demonstrate the heterogeneity of the specific zone in terms of the molecular events occurring. Major factors deeply involved in these biphasic phenomena are the bioactive compound per se, the dose level, the duration of exposure, the cell, tissue or even organ exposed to and, of course, the biomarker examined. In the end, the molecular fate is a complex toxicological event, based on beneficial and detrimental effects, which, however, are poorly understood to date. [ABSTRACT FROM AUTHOR]

Wine is an alcoholic beverage of complex composition obtained through the fermentation of grape must. The consumption of wine has already been associated with a multitude of beneficial effects due to its high polyphenolic content. In this study, four Greek emblematic wines from two red (i.e., Xinomavro and Agiorgitiko) and two white (i.e., Assyrtiko and Malagouzia) varieties were analyzed for the estimation of their antioxidant profiles. To address this question, we assessed their ability to scavenge both synthetic and endogenous free radicals, such as DPPH•, ABTS+•, OH•, O2−, their potential reducing power, and their antimutagenic and antigenotoxic properties. All varieties exhibited potent antioxidant activity, as indicated by the results of methods above, with the red wines appearing more effective than the white ones regarding antioxidant capacity. Our small-scale study is the first to reveal that these wine varieties may have the ability to scavenge the most reactive endogenous radicals. In the future, this finding must be accompanied by larger studies to fill a knowledge gap in the scientific literature concerning a holistic approach of the in vitro antioxidant action of plant polyphenolic compounds. Conclusively, we believe that wines possess high bioactivity that allow them to settle in the industry of food additives and medicinal products. [ABSTRACT FROM AUTHOR]