Effects of Silybum marianum (L.) Gaertn. (silymarin) extract supplementation on antioxidant status and hs-CRP in patients with type 2 diabetes mellitus: a randomized, triple-blind, placebo-controlled clinical trial.

OBJECTIVE

Diabetes is a serious metabolic disorder and oxidative stress and inflammation contribute to its pathogenesis and complications. Since Silybum marianum (L.) Gaertn. (silymarin) extract is an antioxidant with anti-inflammatory properties, this randomized clinical trial was conducted to evaluate the effects of silymarin supplementation on oxidative stress indices and hs-CRP in type 2 diabetes mellitus patients.

METHODS

For the present paralleled, randomized, triple-blinded, placebo-controlled clinical trial, 40 type 2 diabetes patients aged 25-50 yr old and on stable medication were recruited from the Iranian Diabetes Society and endocrinology clinics in East Azarbayjan (Tabriz, Iran) and randomly assigned into two groups. Patients in the silymarin treatment group received 140 mg, thrice daily of dried extracts of Silybum marianum (n = 20) and those in the placebo group (n = 20) received identical placebos for 45 days. Data pertaining to height, weight, waist circumference and BMI, as well as food consumption, were collected at base line and at the conclusion of the study. Fasting blood samples were obtained and antioxidant indices and hs-CRP were assessed at baseline, as well as at the end of the trial.

RESULTS

All 40 patients completed the study and did not report any adverse effects or symptoms with the silymarin supplementation. Silymarin supplementation significantly increased superoxide dismutase (SOD), glutathione peroxidase (GPX) activity and total antioxidant capacity (TAC) compared to patients taking the placebo, by 12.85%, 30.32% and 8.43%, respectively (p < 0.05). There was a significant reduction in hs-CRP levels by 26.83% (p < 0.05) in the silymarin group compared to the placebo group. Malondialdehyde (MDA) concentration significantly decreased by 12.01% (p < 0.05) in the silymarin group compared to the baseline.

CONCLUSIONS

Silymarin supplementation improves some antioxidant indices (SOD, GPX and TAC) and decrease hs-CRP levels in T2DM patients.