Silymarin, a compound found within milk thistle, has a cortisol-lowering effect in rats. - GreenMedInfo Summary
Effect of silymarin on metabolic factors of food-restricted over conditioned Wistar rats.
Pak J Biol Sci. 2008 Jul 15;11(14):1835-9. PMID: 18817226
This study was conducted to evaluate the changes in serum metabolic factors of over conditioned pregnant rats treated with silymarin in food restriction condition. Sixty pregnant Wistar rats were divided into five equal groups. All rats received high energy diet before treatments. Control group were fed ad libitum (Non-FR). Rats in other groups received 50% of the food intake of Non-FR group and served as food-restricted (FR) groups. Three of five FR groups received 150, 200 and 400 mg kg(-1) silymarin, respectively (FR-150, 200, 400). Another FR group (FR-Con) and the Non-FR group did not receive any silymarin. Glucose, triglyceride, LDL and HDL cholesterol, total cholesterol, thyroid hormones and cortisol were measured in serum. All factors were significantly different between groups except free-T4 and T4. Serum glucose concentrations in FR-150 and 200 and Non-FR groups were lower than FR-Con and FR-400. Silymarin significantly increased serum triglycerides, LDL cholesterol and cholesterol contents in FR groups. The highest levels of these factors were noted in 200 mg silymarin-treated group. HDL cholesterol was highest in FR-Con; meanwhile FR-200 group had the lowest HDL cholesterol. Serum cortisol decreased in treated and untreated FR groups except FR-150 group. Free-T3 and T3 concentrations in FR-400 and FR-Con groups were higher than the other silymarin treated groups. In conclusion our results indicate that 200 mg kg(-1) of silymarin in Wistar rats is the best dosage to achieve metabolic benefits. Silymarin has positive effects on lipid metabolism and can modulate serum triglyceride and cholesterol concentrations in food restriction condition. Also, the present findings suggest that silymarin under food restriction situation exerts a decreasing effect upon peripheral conversion of T4 to T3.