Inhibitors of oxidation

Cyhexatin [13121 -70-5], tricyclohexylhydroxystannane (147) (mp 195°C), rat oral 540 mg/kg, and fenbutatin oxide [13356-08-6], hexakis-(2-methyl-2-phenylpropyl)distannoxane (148) (mp 138°C), rat oral LD q 2630 mg/kg, are two novel tin acaricides used on deciduous fmits. They are inhibitors of oxidative phosphorylation. 

Furan [110-00-9] M 68.1, b 31.3°, d 1.42, n 1.4214. Shaken with aqueous 5% KOH, dried with CaS04 or Na2S04, then distd under nitrogen, from KOH or sodium, immediately before use. A trace of hydroquinone could be added as an inhibitor of oxidation. 

Inhibitors of Oxidative Phosphorylatioi Unconplers Disrupt die Coupling of Electron Transport and ATP Synthase ATP Exits die Mitochondria via an ATP-ADP Transloca.se... 

Any substance capable of reacting with free radicals to form products that do not reinitiate the oxidation reaction could be considered to function as free-radical traps. The quinones are known to scavenge alkyl free radicals. Many polynuclear hydrocarbons show activity as inhibitors of oxidation and are thought to function by trapping free radicals [25]. Addition of R to quinone or to a polynuclear compound on either the oxygen or nitrogen atoms produces adduct radicals that can undergo subsequent dimerization, disproportionation, or reaction with a second R to form stable products. 

Mechanistic studies have shown that TBT and certain other forms of trialkyltin have two distinct modes of toxic action in vertebrates. On the one hand they act as inhibitors of oxidative phosphorylation in mitochondria (Aldridge and Street 1964). Inhibition is associated with repression of ATP synthesis, disturbance of ion transport across the mitochondrial membrane, and swelling of the membrane. Oxidative phosphorylation is a vital process in animals and plants, and so trialkyltin compounds act as wide-ranging biocides. Another mode of action involves the inhibition of forms of cytochrome P450, which was referred to earlier in connection with metabolism. This has been demonstrated in mammals, aquatic invertebrates and fish (Morcillo et al. 2004, Oberdorster 2002). TBTO has been shown to inhibit P450 activity in cells from various tissues of mammals, including liver, kidney, and small intestine mucosa, both in vivo and in vitro (Rosenberg and Drummond 1983, Environmental Health Criteria 116). 

Much information about the respiratory chain has been obtained by the use of inhibitors, and, conversely, this has provided knowledge about the mechanism of action of several poisons (Figure 12-7). They may be classified as inhibitors of the respiratory chain, inhibitors of oxidative phosphorylation, and uncouplers of oxidative phosphorylation. 

With aromatic compounds that have benzylic sites, the peroxidation is easy. An apparatus in which tetrahydronaphthalene was distilled detonated. It was assumed that this accident was linked to the concentration of peroxide formed in contact with oxygen. When using phenols as inhibitors of oxidation (and polymerisation too) for all these compounds, this avoids these riste. 

Aryl phosphites are widely used as inhibitors of oxidation. Phosphites react with hydroperoxides and are oxidized into phosphates by the following stoichiometric reaction [1-10] ... 

AD Aslanov. Organic Disulfides as Inhibitors of Oxidative Processes, Cand. Sci. (Chem.) Thesis Dissertation, Inst. Chem. Phys., Chernogolovka, 1985 [in Russian]. 

Tilly, l.L. and TiUy, K.I., 1995, Inhibitors of oxidative stress mimic the abihty of foUicle-stimulating hormone to supress apoptosis in cultured ovarian foUicles. Endocrinology 136 242-252... 

Carbon black and many polynuclear hydrocarbons are effective inhibitors of oxidation. Their antioxidant properties are believed to arise from their ability to trap free radicals. 

Effects of Valinomycin on Oxidative Phosphorylation When the antibiotic valinomycin is added to actively respiring mitochondria, several things happen the yield of ATP decreases, the rate of 02 consumption increases, heat is released, and the pH gradient across the inner mitochondrial membrane increases. Does valinomycin act as an uncoupler or an inhibitor of oxidative phosphorylation Explain the experimental observations in terms of the antibiotic s ability to transfer K+ ions across the inner mitochondrial membrane. 

Wing LM, Miners JO. Cotrimoxazole as an inhibitor of oxidative drug metabolism effects of trimethoprim and sulphamethoxazole separately and combined on tolbutamide disposition. Br J Clin Pharmacol 1985 20(5) 482-5. 

There is evidence that long-term phosphine exposure by individuals involved in the application of pesticides resulted in chromosome damage. Chronic exposure to very low levels of phosphine may result in altered motor, visual, and speech skills. Neither aluminum phosphide nor phosphine gas exhibit carcinogenicity in humans, or result in reproductive or developmental effects. Although definitive evidence is lacking, it is assumed that phospine is an in vivo inhibitor of oxidative phosphorylation. 

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