Oxine antibacterial action

The Influence of Chemical Constitution on Antibacterial Activity. Part V. The Antibacterial Action of 8-Hydroxy quinoline (Oxine). 

Because of the inductive effect of the second nitrogen atom, neither the high stability constant nor the high antibacterial action of oxine is quite reached (the latter falls short by only one twofold serial dilution). However, the last seven substances in Table 11.9 all have stability constants of the same order. For these seven substances, the antibacterial action runs parallel to the partition coefficient, which establishes the correlation. 

That the antibacterial action of oxine 11,24) is due to chelation was shown as follows (Albert et al, i947) Oxine has long been used in chemical... 

Chelating agents such as oxine (8-hydroxyquinoline), Figure 9.3, have had their antibacterial activity extensively explained in terms of metal sequestration and activation and the system is something of a classic case [1], Oxine is bacteriocidal only in the presence of iron(III) and its action... 

Because parasites are dependent on the host cell for nutrients and essential components, the arguments mentioned previously for alteration of the optimal metal concentration and its application to antibacterial and antiviral therapy are equally valid in the case of parasites. The sequestration of zinc and subsequent biochemical effects may present an example of this and the behaviour is somewhat reminiscent of the early and classic demonstration of the mode of action of 8-hydroxyquinoline (oxine). This reagent is also trypanocidal and, as with bacterial systems, cobalt protects against the lethal action [88]. The mode of action of oxine is presumably the same as for bacteria (see Chapter 9). Other chelating agents studied in... 

It is easy to see from Table 2.3 that oxine (0.01 mM) is biologically inert, but becomes bactericidal in the presence of a similar quantity of iron. Clearly the toxic agent is neither oxine nor iron, but the oxine-iron complex. When broth replaced water, no added iron was necessary because it was present in the medium. When the concentration of oxine was increased to 1.25 mM, the bactericidal action disappeared. This was attributed to formation of a non-antibacterial 2 i-oxine-iron complex because, when sufficient extra iron was added to the broth so that the i i complex was re-formed, full bactericidal properties were restored (Albert, Gibson, and Rubbo, 1953). 

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