Dehydroflavonolignans from Silymarin Potentiate Transition Metal Toxicity In Vitro but Are Protective for Isolated Erythrocytes Ex Vivo
Abstract
In this study, current knowledge on metal chelation activity of dehydroflavonolignans was extended. Not previously tested 2,3-dehydrosilychristin (DHSCH) showed its ability to chelate and reduce both iron and copper. 2,3-Dehydrosilybin (DHS) and DHSCH were further tested for metal-based Fenton chemistry.
Neither of these two compounds was able to block the iron-based Fenton reaction and, in addition, they mostly intensified hydroxyl radical production. In the copper-based Fenton reaction, the effect of DHSCH was again prooxidant or neutral, while the effect of DHS was profoundly condition-dependent.
DHS was even able to attenuate the reaction under some conditions. Interestingly, both compounds were strongly protective against the copper-triggered lysis of red blood cells.