Exercise, depletion of antioxidants and antioxidant manipulation

Abstract

Strenuous physical activity is known to increase the production of reactive oxygen species (ROS), associated with depletion of antioxidant defence. In the present work we evaluated the level of lipid peroxidation and antioxidant components in blood of sportsmen under resting conditions and compared the data obtained with those in age- and sex-matched sedentary controls. A significant increase was noted in the levels of thiobarbituric acid reactive substances (TBARS) and conjugated dienes while a decrease was observed in ascorbic acid and glutathione levels in sportsmen. alpha-Tocopherol was unaltered in plasma of sportsmen as compared to controls. The activity of superoxide dismutase was increased (52 per cent) and glutathione peroxidase was decreased (43 per cent) in the erythrocytes of sportsmen compared to controls. Basal glutathione levels were negatively correlated with conjugated dienes and maximal oxygen uptake (VO2max) of the subjects. Dietary supplementation with antioxidant vitamins has been shown to be beneficial in combating oxidative stress without enhancing performance while exogenous glutathione was found to influence the endurance capacity of athletes. Such studies demonstrate the critical role played by glutathione and suggest that intervention trials should include a mixture of antioxidants rather than a single antioxidant.

Alpha-tocopherol supplementation prevents the exercise-induced reduction of serum paraoxonase 1/arylesterase activities in healthy individuals

“…In addition, TAS was significantly increased before training in players with a-T addition as compared with those without at the same time of study. This finding is an agreement with our previous observations (Tsakiris et al, 2006) and indicates an increase in antioxidant action of the vitamin, which minimizes the baseline (pre-training) free radical production and subsequent lipid peroxidation process (Rokitzki et al, 1994;Balakrishnan and Anuradha, 1996;Singh and Jialal, 2004). Interestingly, TAS was decreased in the players posttraining (group D), possibly indicating tissue depletion of other antioxidants (Rokitzki et al, 1994;Balakrishnan and Anuradha, 1996;Singh and Jialal, 2004) since a-T level was not significantly changed in the sera of athletes of this group.…”

Augmentation of antioxidant system: Contribution to antimalarial activity of Clerodendrum violaceum leaf extract

“…Vitamin E is a lipid soluble vitamin and its main function is to prevent the peroxidation of membrane phospholipids and avoid cell damage through its antioxidant action (Herrera and Barbas, 2001;Padayatty et al, 2003). Selenium protects the cells by inhibiting free oxygen radical production but is best known for its role in glutathione enzyme system (Balakrishnan and Anuradha, 1998;Yalçin et al, 2003). Furthermore, vitamin E is transported by selenoproteins (Alfin-Slater and Morris, 1963).…”

Black grape extract supplementation attenuates blood oxidative stress in response to acute exercise

“…Physical exercise, especially of high intensity, is generally recognized as a factor inducing an oxidative stress, while the degree of prooxidative changes is determined by the exercise intensity and time course [2,28]. This was documented by Goto et al [10], who applied a cycloergometer physical exercise test in a study of three groups of young men, with the exercise intensity of 25, 50 and 75% of VO2max, respectively, for a 12-week period.…”