Nitrofurans systemic antibacterial

Nitrofuran An antibacterial drug that damages cellular respiratory systems. 

Nitrofuran antibacterials are synthetic compounds that are substitution products of the 5-nitrofuran nucleus, differing in the substituent at position 2. This substituent may be an azomethine group connected with other ring systems, or an alkyl, acyl, hydroxyalkyl, or carboxyl group, free or esterified. All these antibacterials are susceptible to photolysis, particularly by sunlight, and manipulations must be carried out under subdued light. 

Nitrofurazone. 2-[5-Nitro-2-furanyl)methylene]hydrazinecarboximide, the first nitrofuran to be employed clinically, is prepared from 5-nitro-2-furancarboxaldehyde and semicarbazide (19). This product has seen clinical use topically as an antibacterial, for systemic appHcation for bacterial infections in poultry and swine, and also has been employed as a food additive. In rats, nitrofurazone is hydroxjiated at the 4 position of the fiiran moiety (27). The involvement of nitreninm ions has also been postulated in the mechanism of action of nitrofurazone (38). 

The mechanism of antibacterial action of the furan derivatives is unknown. However, the reduced forms of nitrofurans are highly reactive and are thought to inhibit many bacterial enzyme systems, including the oxidative decarboxylation of pyruvate to acetylcoenzyme A. Nitrofurans (see list in Table 1.7) are bacteriostatic but, at high concentrations, can be bactericidal to sensitive organisms. Both chromosomal and plasmid-mediated mechanisms of resistance to nitrofurantoin occur, and these most commonly involve the inhibition of nitrofuran reductase. 

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