Radical inhibition

Table 5. Free-Radical-Inhibiting Antioxidants or Reductants Useful in Cosmetics ...

Kono, Y. and Friedovich, I. (1982). Superoxide radical inhibits catalase. J. Biol. Chem. 257, 5751-5754. 

K. F., Gorey, T.F. and Fitzpatrick, J.M. (1990). Free radical inhibition and serial chemiluminescence in evolving experimental pancreatitis. Br. J. Surg. 77, 1256-1259. 

The aggregation of platelets contributes to the development of atherosclerosis and to the formation of acute thrombus. The activated platelets that adhere to the vascular endothelium generate lipid peroxides and oxygen free radicals, inhibiting the endothelial formation of prostacyclin and nitric oxide. 

Oxygen radical inhibition. Seed oil, administered to rats at a concentration of 8% of diet, produced equivocal effect on macrophages. Capsaicin or curcumin enhanced the effecH . ... 

Anti-inflammatory activity. Extract of the green seed, administered externally to adult with skin inflammations by free radical inhibition at a concentration of 1%, was active . 

When the radical inhibition reaches its theoretical maximum, ethylene is not produced and the value of TOSC is equal to 100 [3]. 

Kazinol F (31) Antioxidant activity (scavenging free radicals) Inhibition of tyrosinased [341 [34]... 

A variation on the aryne mechanism for nucleophilic aromatic substitution (discussed above, Scheme 2.8) is the SrnI mechanism (see also Chapter 10). Product analysis, with or without radical initiation or radical inhibition, played a crucial role in establishing a radical anion mechanism [21]. The four isomeric bromo- and chloro-trimethylbenzenes (23-X and 25-X, Scheme 2.9) reacted with potassium amide in liquid ammonia, as expected for the benzyne mechanism, giving the same product ratio of 25-NH2/23-NH2 = 1.46. As the benzyne intermediate (24) is unsymmetrical, a 1 1 product ratio is not observed. 

Dipyridamole has also been shown to have antioxidant effects (19). Antioxidants act to remove harmful reactive-oxygen species and protect low-density lipoproteins (LDL) from oxidation oxidized LDL plays a key role in the development and propagation of atherosclerosis. The antioxidant effects of dipyridamole may be both direct (by scavenging oxygen and hydroxyl radicals, inhibiting lipid peroxidation and oxidative modification of LDL) (20-22) and indirect (via adenosine, which reduces superoxide anion generation). Dipyridamole has been shown to be a more effective anioxidant than ascorbic acid, alpha-tocopherol, or probucol (22). 

A previous investigation indicated that the pyrolysis of methyl 3-bromopropionate alone was autocatalyzed by the HBr gas product. However, under maximum free-radical inhibition the reaction was homogeneous, unimolecular and of first order111. Moreover, the acidity of the hydrogen adjacent to the COOCH3 was held responsible for the faster... 

The latter observation is interesting, since coupled with the results of the radical inhibition, this suggests that there are two direct oxidation mechanisms as well as the autoxidation that lead to the products of the TPP Mn-NaBH4-02 reaction a direct oxidation via a free-radical intermediate, but not through the autoxidation in which cyclohexenol formation is inhibited by 2,6-di-t-butyl-p-cresol and another direct uninhibited oxidation that leads to cyclohexene oxide. 

Artonins A B (prenylflavone) Artocarpus heterophyllus (Moraceae) AO/FRS - scavenge DPPH, peroxyl OH radicals, inhibit Cu(II)-mediated LDL oxidation... 

Most generally, spur aspects appear whenever a chemically very active compound (essentially, electron scavengers) is present in the solid matrix, either as a normal constituent or as an additive. This has been demonstrated recently in a variety of irradiated polymers, where radiolysis of the matrix induces the production of either free radicals, inhibiting Ps formation by electron scavenging, or of trapped electrons, enhancing the Ps formation probability, depending on the temperature [41]. 

These compounds are similar to such industrial stabilizers as Sanduvor V.5.4 - 2 - ethyl - 2 - ethoxydiphenyloxamide and Sanduvor V.5.4 - 5 - tretbutyl - 2 - etoxy -ethyldiphenyloxamide [68]. Stabilizing effect of such compounds is realized mainly according to physical mechanism of stabilization reactions of radical inhibition are improbable [69]. 

Doxorubicin . Intercalator, forms free radicals, inhibits topoisomerase Hodgkin s (ABVD), breast, endometrial, lung, ovarian CA BMS—delayed CHF (dexrazoxane is an iron-chelating agent preventing the formation of free radicals it is not a free radical trapper ), alopecia, vesicant, radiation recall ... 

These results suggest that the process of bacterial infection and neutrophil inflammation in chronic airway inflammation will be commonly improved by treatment with 14- and 15-membered ring macrolides. Modes of action include antineutrophil activities, inhibition of IL-8, decreasing oxygen radicals, inhibitions of LTB4 and defensin, and further improvement of mucociliary clearance [90]. 

These compounds and their various derivatives prepared by Curtius and his pupils are white crystalline compounds, forlthe most part soluble with difficulty in cold water. Some of them give the biuret reaction, but others do not, in particular the less complex compounds where the influence of the acid radical inhibits the reaction, although the compounds possess the exact conditions, as determined by Schiff, for the positive exhibition of the reaction. 

For example CLERICI attempted to probe the radical or non radiclal nature of the intermediate. Unfortunatly, one is never sure that in this restricted access zeolites, the usual radical inhibiters would or would not intercept the radical intermediate if formed at the inner sites (82). 

Methyl-l-phenyl-2-pyrazolin-5-one (MCI-186) is a potent scavenger of hydroxyl radicals inhibiting not only hydroxyl radicals but iron-induced peroxidative injury (Watanabe et al. 1988, Muroto et al. 1990). After the reaction with peroxy radicals, MCI-186 changes into 2-oxo-3-(phenylhydrazone)-butanoic acid (Yamamoto et al. 1996, Kawai et al. 1997). 

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