Comparative effects of silymarin and vitamin E supplementation on oxidative stress markers, and hemoglobin levels among patients on hemodialysis.

BACKGROUND: The incidence of accelerated atherosclerosis among patients on hemodialysis is very high and oxidative stress (OS) is a potentially major contributor to their morbidity and mortality. OBJECTIVE: To evaluate the effects of Silymarin and/or vitamin E on OS markers and hemoglobin levels in patients on hemodialysis. METHODS: Eighty patients on hemodialysis were randomized into four groups: Group 1 received silymarin 140 mg 3 times daily; Group 2 received vitamin E 400 IU/day; Group 3 received silymarin 140 mg 3 times daily and vitamin E 400 IU/day; and Group 4 was the control. Samples were obtained at baseline and on day 21 for measurement of malondialdehyde (MDA), red blood cell (RBC) glutathione peroxidase (GPX), and hemoglobin. RESULTS: Combination of silymarin and vitamin E led to a reduction in the MDA levels (7.84 ± 1.84 vs. 9.20 ± 2.74 nmol/mL; p = 0.008). There was a significant increase in RBC GPX levels in all treatment groups compared with controls after 3 weeks. This was more pronounced in the group receiving combination compared with the group receiving vitamin E or the control group (5.78 ± 3.51, 4.22 ± 1.63, and 3.16 ± 1.89 IU/grHb, respectively; p < 0.001). There was also a significant increase in mean hemoglobin of all treatment groups compared with the control. CONCLUSIONS: Oral supplementation with silymarin and vitamin E leads to reduction in MDA, increase in RBC GPX, and increase in hemoglobin levels in patients with end-stage renal disease. Studies with larger sample sizes and longer follow-up are required to investigate the effect of silymarin on cardiovascular outcomes and erythropoietin requirement.

Silymarin and milk thistle extract may prevent the progression of diabetic nephropathy in streptozotocin-induced diabetic rats.

OBJECTIVES: To investigate the effect of silymarin and milk thistle extract on the progression of diabetic nephropathy (DN) in rats. METHODS: Diabetes was induced with a single intraperitoneal (IP) injection of streptozotocin (STZ) (60 mg/kg). Silymarin (100 mg/kg/d) or the extract (1.2 g/kg/d) was gavaged for 4 weeks. Blood glucose (BS), serum urea (S(u)), serum creatinine (S(cr)), and 24-h urine protein (Up) were measured and glomerular filtration rate (GFR) was calculated. Concentration of thiobarbituric acid reactive species (TBARS) and activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were evaluated in the renal tissue. RESULTS: Data were expressed as mean +/- SEM. Silymarin or the extract had no significant effect on BS, S(cr), and GFR. Both milk thistle extract and silymarin, respectively, decreased S(u) (mg/dL) (87.1 +/- 7.78, p < 0.001; 84.5 +/- 7.15, p < 0.001), Up (mg) (5.22 +/- 1.56, p = 0.014; 5.67 +/- 0.86, p = 0.034), and tissue TBARS (nmol/mg protein) (0.67 +/- 0.04, p < 0.001; 0.63 +/- 0.07, p < 0.001) in diabetic rats, compared to diabetic control (DC) (S(u): 131.0 +/- 4.55, Up: 8.3 +/- 0.84, TBARS: 0.94 +/- 0.06). Both the extract and silymarin could increase the activity of CAT (IU/mg protein) (25.5 +/- 4.0, p = 0.005; 20 +/- 1.8, p = 0.16) and GPx (IU/mg protein) (0.86 +/- 0.05, p = 0.005; 0.74 +/- 0.04, p = 0.10), respectively, in diabetic rats compared to DC (CAT = 14.4 +/- 2.0, GPx = 0.57 +/- 0.02). CONCLUSION: Milk thistle extract, to a lesser extent silymarin, can attenuate DN in rats possibly by increasing kidney CAT and GPx activity and decreasing lipid peroxidation in renal tissue.