Enzymatic antioxidants

Bobek P, Ozdin L and Hromadova M. 1998. The effect of dried tomato, grape and apple pomace on the cholesterol metabolism and antioxidative enzymatic system in rats with hypercholesterolemia. Nahrung 42(5) 317— 320. 

Hernandez-Ledesma, B., D avalos, A., Bartolom e, B., and Amigo, L. (2005). Preparation of antioxidant enzymatic hydrolysates from a-lactalbumin and p-lactoglobulin. Identification of active peptides by HPLC-MSMS. ]. Agric. Food Chem. 53,588-593. 

Both in MCI and AD patients, mean plasma levels of nonenzymatic antioxidants and activity of antioxidant enzymes appeared to be lower than in controls, with no parallel induction of antioxidant enzymes (Keller et al., 2005). In order to explain these results it has been suggested that the increased free radical production in MCI might lead to a rapid consumption of plasma antioxidants without a simultaneous activation of new molecules of antioxidant enzymes. Individuals with MCI, and subsequently with AD, are likely to have an inadequate antioxidant enzymatic activity, unable to counteract the increased production of free radicals during the pathogenesis of the disease. 

Gerdin E, Tyden O, Eriksson UJ. The development of antioxidant enzymatic defense in the perinatal rat lung. Activities of superoxide dismutase, glutathione peroxidase and catalase. Pediatr Res 19 (1985) 687-691. 

Cellular antioxidants Enzymatic Catalase H2O2 02 + 2H2O... 

Porta, C. et ah. Antioxidant enzymatic system and free radicals pathway in two different human cancer cell lines, H r/ca cer Res., 16 (5A), 2741,1996. 

Antioxidants are snbstances that are able to protect organisms from oxidative stress. A distinction is drawn between three types of antioxidants enzymatic antioxidants, nonenzymatic antioxidants, and repair enzymes. 

Cancer chemoprevention has a potential impact on the rates of cancer incidence through modulation of initiation and promotion stages (24). Epidemiological studies have suggested that sufficient upt e of tea polyphenols may reduce the risk of cancer through their role in the metabolism of carcinogens, antioxidant enzymatic activities and scavenging of fi radicals... 

MANZOCCO L, CALLiGARis s, MASTROCOLA D, NicoLi M c and LERici c R (2001) Review of non-enzymatic browning and antioxidant capacity in processed foods . Trends Food Sci Technol, 11 340-6. 

NICOLI M c, CALLIGARIS s and MANZOCCO L (2000) Effect of enzymatic and chemical oxidation on the antioxidant capacity of catechin model systems and apple derivatives , JAgric Food Chem, 48 (10) 4576-80. 

Superoxide anion scavenging activity of the enzymatically synthesized poly(catechin) was evaluated. Poly(catechin), synthesized by HRP catalyst, greatly scavenged superoxide anion in a concentration-dependent manner, and almost completely scavenged at 200 p.M of a catechin unit concentration. The laccase-catalyzed synthesized poly(catechin) also showed excellent antioxidant property. Catechin showed pro-oxidant property in concentrations lower than 300 jlM. These results demonstrated that the enzymatically synthesized poly(catechin) possessed much higher potential for superoxide anion scavenging, compared with intact catechin. 

Injury (either physical or chemical) to the comeal endothelial cells has a marked efiect on occular function as these cells are responsible for maintaining the thickness and clarity of the cornea, yet they cannot be replaced if damaged. Immunohistochemical studies have revealed that enzymatic antioxidant defences, SOD, CAT and GSHPx, are similarly distributed in the corneal epithelium and endothelium (Rao etal., 1985 Attala et d., 1987, 1988). Other antioxidants include ascorbate, carotenoids and vitamin E (Fleath, 1962). 

Ascorbate is known to act as a water-soluble antioxidant, reacting rapidly with superoxide, hydroxyl and peroxyl radicals. However, reduced ascorbate can react non-enzymatically with molecular oxygen to produce dehydroascorbate and hydrogen peroxide. Also, ascorbate in the presence of light, hydrogen peroxide and riboflavin, or transition metals (e.g. Fe, Cu " ), can give rise to hydroxyl radicals (Delaye and Tardieu, 1983 Ueno et al., 1987). These phenomena may also be important in oxidative damage to the lens and subsequent cataract formation. 

Non-enzymatic glycosylation Polyol pathway Reduced antioxidant resen/e Activated neutrophils, etc. 

Lian, F. and X. D. Wang. 2008. Apo-lO -lycopenoic acid, an enzymatic metabolite of lycopene, induces Nrf2-mediated expression of phase II detoxifying/antioxidant enzymes in human bronchial epithelial cells. Int J Cancer (in press). 

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