Lab animals were able to swim for longer when given oral doses of EGCG over the course of a month, according to data published in the PubMed-listed Pharmacognosy Magazine.
The data also revealed that the EGCG-supplemented animals had lower levels of lactic acid in their blood, and reduced levels of creatine kinase (a marker of muscle damage) and malondialdehyde (MDA), a marker of oxidative stress, compared to non-supplemented animals.
“The finding of the study suggests that EGCG can be used to design nutraceutical supplements aimed to facilitate recovery from fatigue and attenuate exhaustive exercise-induced oxidative damage,” wrote scientists from Liaoning Normal University in China.
The study adds to an ever-growing body of science supporting the potential benefits of green tea (Camellia sinensis) and its constituents, most notably EGCG (epigallocatechin gallate).
Green tea contains between 30% and 40% of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3% and 10%. Oolong tea is semi-fermented tea and is somewhere between green and black tea. The four primary polyphenols found in fresh tealeaves are EGCG, epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC).
The Chinese scientists divided lab mice into four groups: One control group and three groups, which received different oral doses of EGCG (50, 100, and 200 mg/kg) for 28 days. On the last day of experiment, the animals were subjected to a forced swimming exercise, which “has been used extensively for the evaluation of the anti-fatigue properties of novel compounds”, explained the researchers.
The results showed that the time to exhaustion increased with increasing EGCG dose, while lactic acid, creatine kinase, and MDA levels decreased.
The researchers also found that the EGCG-fed animals had increased glycogen content in the liver and muscles, while the activities increased of antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxidase.
“In this study, the data showed that EGCG significantly increased liver and muscle glycogen contents of mice, which indicated that EGCG could enhance exercise tolerance,” wrote the researchers.
“[T]he present results further support that EGCG had anti-fatigue effect in a dose-dependent manner and at the dose of 200 mg/kg exhibited the optimal effect. Combined with previous studies, anti-fatigue mechanisms of EGCG may possibly be due to its protective effects on corpuscular membrane by prevention of lipid oxidation via modification of several antioxidant enzyme activities.
“Further study is warranted to elucidate its molecular mechanism and anti-fatigue-related gene regulation,” they concluded.
Source: Pharmacognosy Magazine
April-June 2017, Volume 13, Number 50, Pages 326-331. doi: 10.4103/0973-1296.204546
“Anti-Fatigue Effect of Green Tea Polyphenols (-)-Epigallocatechin-3-Gallate (EGCG)”
Authors: Y.S. Teng, D. Wu