Catechins contained in green tea do not suppress oxidative stress in cells, and vice versa provoke it. This conclusion came scientists of the Higher Technical School in Zurich (Switzerland), who studied how catechins affect Caenorhabditis Elegans nematodes. Paradoxical is that in this case it is explained by the benefits of green tea for health: oxidative stress enhances the effect of antioxidant protection. The article with the results of scientific work was published in the AGING journal, briefly describes this in a press release on MedicalXpress.
It is known that green tea contains epicatechin-3-gallate (ECG) and epigalocatehin-3-gallate (EGCG), which belong to polyphenols and, as it is believed to renew their lives. It was still assumed that catechins neutralize oxygen radicals formed in cells during oxidative stress, and thereby prevent damage to cells or DNAs. However, in a new study, scientists have discovered that catechins cause short-term strengthening of oxidative stress.
When the catechins increased the production of active forms of oxygen, the genes of genes producing certain antioxidant enzymes, such as superoxiddismutase (SOD) and Catalase (CTL), which were neutralized by oxygen radicals were activated. Thus, polyphenols in green tea act as prooxidants who strengthen the capacity of the body to cope with oxidative stress. As a result, the catechins in the green tea extended life and improved the physical indicators of nematodes.
Interestingly, sport and restriction of calories consumed, which are also a way to improve health and extend life, have a similar effect. Physical exertion in the short term strengthen the oxidative stress, thereby improving the body’s protective forces. The use of a smaller calorie also extends life from model animals using the same mechanisms.
However, scientists do not advise to take extracts or concentrates of green tea that can have a toxic effect. Catechins in high doses suppress the work of mitochondria to such an extent that the cell death occurs, which is especially dangerous for the liver. Although a large number of catechins are contained in Japanese grade of green tea, other varieties also include a sufficient amount of these polyphenols. At the same time, black tea contains a much lower level of catechins, since they are largely destroyed in the fermentation process.