Antioxidants in vitro

There have been more than 20 studies relating to the prevention of atherosclerosis by antioxidants. In vitro, several studies have shown that antioxidant treatment (e.g. vitamin E) inhibits both oxidation and the formation of cytotoxic LDL (Steinbrecher etal., 1984 Par-thasarathy etal., 1986 Esterbauer etal., 1987). In vivo, vitamin E supplementation prevents LDL oxidation in... 

The metabolism and bioavailability of isoflavonoids is likely to be of crucial importance to their ability to help protect human health against disease. Many studies have been published on the metabolism and bioavailability of isoflavones in adults. The metabolism of isoflavones is of particular interest because the potency of isoflavone metabolites differs from that of the parent compounds. The daidzein metabolite equol is three times as potent as is daidzein in an endometrial tumor line. Equol is also a more potent antioxidant in vitro (see Sections 7.3.5 and 7.4.2) ° and the clinical significance of the ability to form equol has been considered in depth. ... 

Quantitative Studies on Green Tea Constituents in Comparison with Other Known Antioxidants In Vitro Assays... 

In its biochemical functions, ascorbic acid acts as a regulator in tissue respiration and tends to serve as an antioxidant in vitro by reducing oxidizing chemicals. The effectiveness of ascorbic acid as an antioxidant when added to various processed food products, such as meats, is described in entry on Antioxidants. In plant tissues, the related glutathione system of oxidation and reduction is fairly widely distributed and there is evidence that election transfer reactions involving ascorbic acid are characteristic of animal systems. Peroxidase systems also may involve reactions with ascorbic acid In plants, either of two copper-protein enzymes are commonly involved in the oxidation of ascorbic acid. 

Burton, G.W., Ingold, K.U. 1981. Auto-oxidation of biological molecules. I. The antioxidant activity of vitamin E and related chain breaking phenolic antioxidants in vitro. J. Am. Chem. Soc. 103, 6472-6477. 

Sommer D, Fakata KL, Swanson SA, Stemmer PM. 2000. Modulation of the phosphatase activity of calcineurin by oxidants and antioxidants in vitro. Eur J Biochem 267 ... 

Because they lack the phenolic hydrogen, esters are more stable than free vitamers, but they are not antioxidants in vitro. Tocopheryl esters hydrolyze slowly under, eg., acidic aqueous systems, thus providing antioxidant activity for emulsions, soft drinks and some dairy products (Schuler, 1990). 

Melatonin, a hormone of the pineal gland which is responsible for the circadian rhythms, is also a strong antioxidant in vitro. However, the concentrations of this hormone in vivo are far below the effective range. 

The use of extracts from rosemary as food preservatives is well established [25] the phenolic compounds obtained from this source have been shown to act as antioxidants in vitro and reduce the oxidation of dietary lipids in a dose-dependant manner [26]. The constituents of rosemary considered responsible for the majority of this antioxidant activity are rosmarinic acid, carnosol, and carnosic acid [14]. 

Tsepalo V, V. F. A Method of Quantitative Analysis of Antioxidants by means of a Model Reaction of Initiated Oxidation, In Investigation of Synthetic and Natural Antioxidants In vitro and In vivo, Moscow, 1992 (in Russian). 

Scott, G. Antioxidants in vitro and in vivo. Chem. Britain 21, 648-653 (1985). 

Rice-Evans C. Implications of the mechanisms of action of tea polyphenols as antioxidants in vitro for chemoprevention in humans. Proc Soc Exp Biol Med 1999 220 262-266. 

Antimalarial - in vitro against Plasmodium falciparum D-6 (ED50 4.05 pg/mL) and W-2 (ED50 4.47 pg/mL). Antioxidant - in vitro (IC0 200 2.1 pM) in scavenging stable free radical, DPPH. 

Kato, Y., et al. Inhibition of myeloperoxidase-catalyzed tyrosylation by phenolic antioxidants in vitro. Biosci. Biotechnol. Biochem. 67(5), 1136-1139 (2003)... 

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