# Retrospecting the Antioxidant Activity of Japanese Match Green Tea-Lack of Enthusiasm?
## 2 Antioxidant Activity of Green Tea  
The antioxidant activity of green tea is one of the highly vouched-for health benefits of green tea. The antioxidant activity of green tea has been elaborately reviewed by [PERSON] et al. [22]. It is likely that the basis for the superior bioactive properties of green tea polyphenols in vitro and in vivo could be due to their antioxidant or pro-oxidant properties. This could be the very fundamental basis of the various health benefits manifested by green tea. A clear understanding of the antioxidant mechanism of green tea becomes crucial to decoding the mechanism of interaction of green tea bioactives with biological cells and disease. Free radicals are usually generated via cellular respiration and normal metabolic processes. The reactive oxygen species (ROS) that are produced via these processes are in turn associated with various physiological and pathological processes. ROS include superoxide anion free radicals (\({}^{\bullet}\)O\({}^{-}\)2), hydroxyl free radicals (\({}^{\bullet}\)OH), hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)), and the like [23; 24]. At low levels, ROS act as signaling molecules [25]. The accumulation of ROS within the cells occurs because the delicate balance is disturbed and this in turn disrupts the body's antioxidant process. This results in oxidative stress and  
Figure 2: Diverse processing types that determine various teas. cell damage and diseases [26]. There is concrete evidence that free radicals are associated with atherosclerosis, emphysema, and various forms of cancer [27]. Heart diseases, renal diseases and cancers, skin damage by ultraviolet rays, as well as diseases associated with aging result as a consequence of ROS. The hydroxyl groups in the green tea polyphenols' chemical structure invest them with the free-radical scavenging ability. The antioxidant capacity of catechins is directly proportional to the number of hydroxyl groups [28]. Antioxidant capacity differs from tea to tea, and their associated green tea polyphenols have been investigated [29; 30; 31; 32; 33; 34; 35; 36]. [PERSON] et al. (2017) reported the increase in catalase (CAT), glutathione peroxidase (GSH), and superoxide dismutase (SOD) due to (\(-\))-epigallocatechin-3-gallate (EGCG) in rats [37]. These investigations prove that EGCG in green tea can regulate the oxidoreductase system and accelerate the anti-oxidation property of the system [37; 38]. Tea polyphenols are also reported to prevent oxidative stress caused by bacterial infections and intestinal damage [39]. Also, tea polyphenols are confirmed to restore serum total protein levels and also restore tumor necrosis factor-a (TNF-a) and caspase-3 [40] and protect the rat liver from injury through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms. EGCG prevents cancer via inhibiting generation of ROS within the cells. Further, EGCG also influences programmed cell death by blocking DNA synthesis specifically in cancer cells [41]. EGCG has also been reported to stimulate cell proliferation, improve cell membrane integrity, and facilitate cell survival and function under oxidative stress in goat models [42]. In the cell signaling pathway, EGCG plays a pivotal role in regulating apoptosis induced by oxidative stress through protein kinase B (Akt) and c-Jun N-terminal kinase (JNK) signaling pathways. ECG up-regulates mitogen-activated protein kinase (MAPK) and antioxidant response element (ARE) gene expression, triggering the cell's antioxidant defense system into action [43]. EGCG also influences other cellular pathways that are related to the body's antioxidants (nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-kB) [44]. Therapeutic effects combining tea polyphenols and other drugs have also been published [22; 45; 46]. Green tea is also reported to delay aging and avert cancer and neurodegenerative, cerebrovascular, and cardiovascular diseases [47]. Table 1 gives a comparative account of green tea versus matcha tea.