Abstract
BackgroundPotential health benefits are attributed to the antioxidant properties of green tea polyphenolic compounds. The main aim of the study was to evaluate the effects of a six-week green tea extract (GTE) supplementation combined with CrossFit workout on blood antioxidant status and serum brain-derived neurotrophic factor (BDNF) in men.MethodsSixteen young males involved in CrossFit training were randomized into two groups supplemented with GTE or placebo for six weeks. Each participant performed an exercise test for the evaluation of maximum oxygen uptake (VO2max) twice, i.e., before starting (1st trial) and after completing the supplementation combined with CrosFit workout (2nd trial). Venous blood samples were drawn at rest, immediately post-test and after one hour of recovery in order to estimate activities of antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GPx], reduced glutathione [GR]), non-enzymatic antioxidants (reduced glutathione [GSH], uric acid [UA], total phenolics), total antioxidant capacity (FRAP), lipid peroxidation products (TBARS), and BDNF.ResultsExcept for a significantly higher SOD activity and FRAP level recorded at rest and post-exercise in the 2nd trial compared to the corresponding values in the 1st trial, no significant differences were recorded among other assayed measures such as CAT, GPx, GR, GSH and BDNF. Moreover, a percentage increase in FRAP level was twice as high after six weeks’ GTE consumption than after placebo. Regardless of the trial, an increase in plasma UA concentration and a decrease in plasma total phenolics level were observed after exercise test. Plasma TBARS concentrations were significantly higher in PLA group after six weeks’ CrossFit training, while in GTE group they were slightly lower compared to the corresponding values in the 1st trial. Moreover, there was a significant inverse correlation between FRAP and TBARS in the GTE-supplemented group (r = − 0.40, p < 0.05).ConclusionsA six weeks’ consumption of GTE had marginal effect on aerobic capacity and serum BDNF level in CrossFit-trained men, but it caused a marked increase in the blood antioxidant capacity and a moderate attenuation of the training-induced lipid peroxidation.
Highlights
Potential health benefits are attributed to the antioxidant properties of green tea polyphenolic compounds
Except for a significantly higher Superoxide dismutase (SOD) activity (a) recorded at rest and post-exercise in both studied groups (PLA and green tea extract (GTE)) in the 2nd trial compared to the corresponding values in the 1st trial, no significant differences were recorded among other assayed measures such as CAT (b), Glutathione peroxidase (GPx) (c), and Reduced glutathione (GR) (d)
There was opposite tendency towards a slight decrease in total phenolics in the The control placebo group (PLA) group as well as an increase in the GTE-supplemented group in the 2nd trial compared to the corresponding values in the 1st trial
Summary
Potential health benefits are attributed to the antioxidant properties of green tea polyphenolic compounds. Its potential health benefits are mainly attributed to the antioxidant properties of polyphenolic compounds containing the phenolic hydroxyl groups attached to ring structures through acting as hydrogen- or electron-donating free radical and transition metal chelators. They can inhibit the activity of enzymes responsible for reactive oxygen species (ROS) production, such as xanthine oxidase, cyclooxygenase and lipoxygenase [4]. The health effect of polyphenols is associated with their bioavailability Before intestinal absorption, these compounds are hydrolyzed by enzymes or by colonic microflora and in the liver where they are conjugated via methylation, sulfation or glucuronidation [5]. Polyphenols are known to have prooxidant properties both in vitro and in vivo; it can be presumed that their biological effects are not limited to modulation of oxidative stress [6]
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