Ochratoxin A presence in Cabernet Sauvignon wine changes antioxidant activity<i>in vitro</i>and oxidative stress markers<i>in vivo</i>

Ochratoxin A (OTA) is a mycotoxin found in grape products and oxidative stress has been reported as an important mechanism involved in its toxicity, classified as possible carcinogenic to humans. Conversely, phenolics are known bioactive compounds in grapes and display great antioxidant properties. However, the biological effects of the concomitant presence of phenolic compounds and OTA remains unclear. The aim of this study was to evaluate, for the first time, the effect of OTA presence in Cabernet Sauvignon wine on antioxidant activity <i>in vitro</i> and on oxidative stress markers <i>in vivo</i>. In addition, the phenolic composition of wine was evaluated by LC-DAD-MS/MS. <i>In vitro</i> assays were based on spectrophotometric methods, while i<i>n vivo</i> assays were performed evaluating oxidative stress markers in the nematode <i>Caenorhabditis elegans</i>, an alternative model to animal testing. A total of 23 phenolic compounds were identified in the Cabernet sauvignon red wine, including the anthocyanins delphinidin-3-<i>O</i>-glicoside and malvidin-3-<i>O</i>-glicoside, the flavonol quercetin-3-<i>O</i>-glucuronide and the phenolic acids caffeic, verbascoside and caftaric. <i>Trans</i>-resveratrol and <i>trans</i>-piceid were the only stilbenes found in the samples. OTA presence in the red wine was accompanied by reduction in GSH content and increase in hydroxyl radical generation <i>in vitro</i>. The presence of OTA in wine also increased lipoperoxidation and induced overexpression of the antioxidant enzymes superoxide dismutase and catalase <i>in vivo</i>. This study demonstrates that OTA presence in red wine can reduce its antioxidant potential <i>in vitro</i> and induces oxidative stress <i>in vivo</i>, without affecting the phenolic compounds levels in the samples. Thus, this work provides insights into the negative effects of the presence of OTA in wine, not only by its known toxicity, but also by prejudicing the antioxidant potential of wine. It is important to be aware of these effects when developing a complete description of OTA toxicity in humans.