2- nitrobenzoate, reductive metabolism

Helminth parasites have the capacity to reductively metabolize a variety of xenobiotics. Whereas all helminth species examined are able to reduce xenobiotics containing an azo functional group (R—N=N—R ), nitroreduction is not universally present. For example, A. suum and M. expansa reduce both azobenzene and 4-nitrobenzoic acid (20), whereas H. diminuta (21) and Onchocerca gutturosa (22) metabolize only the former. Although azoreductase and nitroreductase have not been purified from helminths, they appear to be confined to the soluble cell fraction and to use NADH, rather than NADPH, as the reduced pyridine cofactor (8). An exception is the nitroreductase from... 

In contrast to the aforementioned monosubstitutions, much less is known about the effect of disubstitution. It appears that such benzamides are resistant to hydrolysis. The metabolic fate of nitromide (3,5-dinitrobenzamide, 4.63), a chicken-feed additive for the prevention of coccidosis, was investigated in rats. The metabolite 3-amino-5-nitrobenzoic acid (4.64), formed by ni-tro reduction and hydrolysis, was excreted in only trace amounts. Nitromide was metabolized mainly via nitro reduction [36], Similarly, no hydrolysis was... 

Although in some animals starvation appears to have effects similar to those of protein deficiency, this is not necessarily the case. For example, in the mouse, monooxygenation is decreased but reduction of p-nitrobenzoic acid is unaffected. In male rats, hexobarbital and pentobarbital hydroxylation as well as aminopyrine A-demethylation are decreased, but aniline hydroxylation is increased. All of these activities are stimulated in the female. Water deprivation in gerbils causes an increase in P450 and a concomitant increase in hexobarbital metabolism, which is reflected in a shorter sleeping time. 

Most studies in the microbial metabolism of nitroaromatic compounds used aerobic microorganisms. In most cases no mineralization of nitroaromatics occurs, and only superficial modifications of the structures are reported. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds reportedly undergo a series of reductions with the formation of amino compounds. For example, trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of ammonia from triaminotoluene is achieved by reductive deamination catalyzed by the enzyme reductive deaminase, with the production of ammonia and toluene. Some sulfate reducers can metabolize toluene to (X) sub 2. Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. Many methanogenic bacteria can reduce nitroaromatic compounds to amino compounds. 

The metabolic behavior of nitrotoluene was studied very early by Jaffe (182, 183). o-Nitrotoluene is converted to o-nitrobenzyl alcohol and o-nitrobenzoic acid in dogs. The alcohol is excreted to the extent of 25 per cent as nitrobenzyl glucuronoside which can be isolated as a complex with urea. o-Nitrobenzoic acid is excreted in an amount corresponding to 10 per cent of the dose fed. No o-nitrobenzylaldehyde was detected although it may be an intermediate. Some reduction of the nitro group also may occur although this was not reported by Jaffe. 

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