Catechin antioxidative activity

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GUO Q, ZHAO B, SHEW s, Hou J, HU J and xiN w (1999) ESR study of the structure -antioxidant activity relationship of tea catechins and their epimers, Biochem Biophys Acta, 1427, 13-23. 

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Kimura, M., Umegaki, K., Kasuya, Y., Sugisawa, A., and Higuchi, M., The relation between single/double or repeated tea catechin ingestions and plasma antioxidant activity in humans, Eur. J. Clin. Nutr., 56, 1186, 2002. 

Kurisawa, M. et al.. Amplification of antioxidant activity and xanthine oxidase inhibition of catechin by enzymatic polymerization. Biomacromolecules, 4, 469, 2003. 

Catechins Peroxidase Teas Antiviral and antioxidant activity... 

Pomegranate peel extracts have also been shown to possess significant antioxidant activity. Albino rats of the Wistar strain were fed a dried methanolic extract from pomegranate peels at 50 mg/kg (in terms of catechin equivalents) followed by carbon tetrachloride (CCl4)-induced oxidative stress. This resulted in preservation of catalase, peroxidase, and superoxide dismutase (SOD) activity to values comparable with control values, whereas lipid peroxidation was brought back by 54% as compared to control.33... 

A variety of antioxidant phytochemicals in apples include catechin, procyanidins, hydroxyciimamates, flavonols, anthocyanins, and dihy-drochalcones. The consumption of apple contributes to the reduced risk of diseases such as cardiovascular disease and some forms of cancer (Boyer and Liu, 2004). In a recent study, the phenolic phytochemical composition and antioxidant activity of 67 varieties of apple cultivars were examined by Wojdylo et al. (2008). The total content of these phytochemicals varied from 0.5 to 2.7% of dry weight. In apple juice, the total phenolic content ranged from 0.02 to 0.1% of juice. Catechin and procyanidins are the major classes of apple phenolics, representing more than 80% of the total content. A small amount of anthocyanin was also found in red apples. The results of this study demonstrated that new varieties of apple, such as Ozark Gold, Julyred, and Jester, had the same... 

At present, the biological activity of tea catechins has been determined mostly with the parent chemicals. EGCG, EGC, EC, and ECG have been shown to possess various biological activities, including antioxidative and free radical scavenger activity when studied in in vitro systems. " Pietta et al. reported that free plasma catechins account for only about 20% of increase in the total antioxidant activity... 

The antioxidant activity of these catechins and the derivatives showed a marked difference depending on the substrate used for evaluation. In bulk corn oil that was oxidized at 50°C epigaUocatechin, epigallocatechin gallate and epicatechin gallate exhibited better antioxidant activity than epicatechin or catechin. These catechins have been very effective in retarding oxidation of polyunsturated fatty acids-rich... 

The antioxidant activity of individual tea polyphenols in different model assays showed a proportional relationship to the number of hydrogen radical donors of catechins. A synergistic effect was observed between tea catechins and caffeine, ascorbic, citric, malic, and tartaric acids and tocopherols (153). Formation of oxidation products of (+)-catechin dirring the antioxidative process has been observed in oxidation model studies. According to the proposed mechanism, (+)-catechin can scavenge four radicals per molecule (154, 155). Yamamoto et al. (156) have summarized the chemistry and application aspects of green tea, especially in relation to using their catechins. 

Both marketers of manufactured superfruit products and the public media have exaggerated the potential antioxidant importance of fruit compounds such as polyphenol pigments (anthocyanins, flavonoids, tannins, catechins, xanthones, and many others). These compounds have antioxidant activity in controlled laboratory conditions, but there is no scientifically confirmed evidence that they have antioxidant roles in the human body. 

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