Anti-Hyperlipidemic and Anti-Atherosclerotic Activities of Silymarins from Cultivated and Wild Plants of Silybum marianum L. with Different Content of Flavonolignans

The object of this study is to evaluate the influence of silymarins from cultivated and wild Silybum marianum L. plants with different content of flavonolignans, especially silibinin on serum lipids levels and on the experimental atherosclerosis development in rabbits fed on high cholesterol-diet (HCD). Forty eight male six-months-old white New Zealand rabbits (1.8-2 kg) were randomly assigned into six equal groups: positive control group - fed on HCD, negative control group- fed on standard laboratory diet and four groups fed on HCD with two different doses (100 and 200 mg/kg/day) of silymarins from cultivated and wild plants. Silymarin extracts were administered via the oral route, once daily for 2 months. Feeding of rabbits on HCD supplemented with both silymarins from cultivated and wild plants at the dose of 200 mg/kg/d caused a significant decrease in levels of total cholesterol, LDL-C and triacylglycerols. On the other hand, administration of silymarin from cultivated plants at the dose of 200 mg/kg/d in the diet enhanced significantly HDL-C serum content of rabbits. Both silymarins, at the dose of 200 mg/kg/d showed a significant inhibition of atherosclerotic plaque formation. Although a clear dose-dependent relationship was observed at the applied doses, but the pharmacological effects of silymarin from wild plants with lower content of silibinin, at the dose of 100 mg/kg/d were compared to those of silymarin of cultivated ones. Our results confirmed the anti-hyperlipidemic and anti-atherosclerotic effects of silymarins from both cultivated and wild milk thistle plants. In addition, the results allowed us to suggest that other constituents rather than silybinin may be responsible for therapeutic effects of silymarin.