Role of quercetin on Caco-2 cells against cytotoxic effects of alternariol and alternariol monomethyl ether

Molds of the genus Alternaria have been reported as contaminants of a variety of food and feed. Alternaria toxins such as alternariol (AOH) and its naturally occurring monomethyl ether (AME) produce cytotoxicity and oxidative stress in cell cultures.On the other hand, it has been proved that natural polyphenols have antioxidant effect. Quercetin (Quer) is a polyphenol present in berries and other commodities which exhibits these effects. The aims were to evaluate the cytotoxicity of AOH, AME and the binary combination of them, and the cytoprotective effect of Quer exposed simultaneously with AOH, AME and the mycotoxin mixture in human adenocarcinoma (Caco-2) cells. The cytotoxicity and the cytoprotective effect were determined by the MTT test after 24 and 48 h of exposure and interactions were evaluated with the isobologram analysis method. Cell viability decreased after 48 h of AOH and AME exposures, being the binary combination more cytotoxic, causing a synergism effect. No cytoprotective effect of Quer against AOH and AME was observed when they were exposed simultaneously in Caco-2 cells. The cytoprotective effect of Quer against mycotoxins (AOH, AME or other different which could present higher cytotoxic effect) depends on the concentration, the presence and the interaction between the compounds in food.