Introduction: Silybum marianum is an annual or biannual herbaceous species of the Asteraceae family. The medicinal effects of this plant are due to the presence of a group of flavonolignans which is called silymarin. It has been suggested that silymarin has anti -inflammatory, antioxidant properties and could stabilize cell membranes and regulate cell permeability and could prevent the appearnance of some of the undesirable muscle damage indices in patients and even athletes. Hence, the aim of this study was to determine the effect of silymarin intake on some mascular damage markers in serum of active males after the one session aerobic exercise.



Methods: Twenty-two active males (mean age 25.09±2.11 years, body fat 13.56±1.94% and VO2max 50.5±4.88 ml/kg-1/min) were divided into two homogenous groups of 11 subjects (supplement and placebo groups) in a semi-experimental, randomized and double-blind design (6 mg.kg-1.day silymarin or Dextrose). After 7-days of supplementation, all subjects participated in aerobic exercise protocol including running on the treadmill at the 0% grade for 30 min with 65-70% HRreserve. Changes in muscle damage indices (total serum CK and LDH, AST) were determined in four phases (baseline, after supplementation period, immediately and 24 hours after the exercise). Data were analyzed by repeated measure ANOVA, bonferroni, and independent t test at α≤0.05 level of significance.



Results: The results showed that after 30 min aerobic exercise, the levels of serum muscle damage enzymes significantly increased immediately and 24 hours after exercise in Silymarin and Placebo groups (P≤0.05). However, after 24 hours of aerobic exercise, all of muscle enzymes activity was signficiantly higher in Placebo group in comparison with Silymarin group (P≤0.05).



Conclusions: Based on the present findings, it could be concluded that silymarin supplementation could significantly decrease further aerobic exercise-induced muscle damage in active males.