Activities of silymarin and its flavonolignans upon low density lipoprotein oxidizability in vitro

Silymarin, a standardized extract from Silybum marianum, inhibited in vitro the copper-induced oxidation of human LDL in a concentration-dependent manner. Silybin, a main flavonolignan of silymarin, appeared to be responsible for this LDL antioxidant effect. Silychristin and silydianin, other flavonolignans of silymarin, acted rather as pro-oxidants, but with regard to their content in silymarin, it did not contribute significantly to the reduction of the total LDL antioxidant capacity of silymarin.