The effect of silymarin on expression of selected ABC transporters in the rat

Silymarin (standardized extract from the seeds of the Silybum marianum) has been used in the supportive therapy of liver diseases and its cytoprotective activity is believed to be based on antioxidant properties. Our previous works showed hypolipidemic effects of silymarin. The ATP-binding cassette (ABC) transporters G5 and G8 play a major role in biliary cholesterol secretion. The ABCA1 transporter plays a significant role in movement of cellular cholesterol to high density lipoproteins. We investigated the possibility that silymarin affects the regulation of lipid metabolism via selected ABC transporters using rats fed a high-cholesterol diet with silymarin. The major finding in this study is that silymarin up-regulated mRNA of ABC transporters (G5, G8 and A1). This result suggests that silymarin positively affects the plasma lipoprotein profile via up-regulation of ABC transporters involved in lipid metabolism. Furthermore, this study shows for the first time that silymarin up-regulates the expression of these ABC transporters at the mRNA level.