Inhibitory action of silibinin on low density lipoprotein oxidation

Low density lipoprotein (LDL) oxidation and smooth muscle cell growth represent key events in atherogenesis. Any mean to reduce these two phenomena may decrease the risk of coronary artery disease and atherosclerosis in general. The effects of silibinin (CAS 22888-70-6) on LDL oxidation and proliferation of vascular smooth muscle cells were evaluated in vitro. Silibinin (50-200 mumol/l) prolonged the lag times of both LDL autooxidation and oxidation by copper by > 50%, as assessed by recordings of diene formation. However, silibinin (up to 500 mumol/l) did not interfere with LDL-stimulated radiolabeled thymidine incorporation. These findings indicate that silibinin, apart from its hepatoprotective effects, has inhibitory properties on LDL oxidation in vitro. Therefore silibinin might represent a novel tool in the prevention and therapy of atherosclerosis.