The Pro-Oxidant Activity of Aluminium

We have recently begun to investigate the basis for the pro-oxidant activity of the 'redox inert' Al3+(aq)! We began by looking at the potential for aluminium to influence the 'reactivity' of the superoxide radical anion, O2-. We proposed that the pro-oxidant activity of aluminium might be explained by it being bound by superoxide to form an aluminium superoxide semireduced radical cation!

O2- + Al3+ <---> AlO22+

Such a complex is predicted based upon metal-superoxide complexes generated under anhydrous conditions and identified by EPR but has yet to be identified under physiological conditions.

 al-superoxide

Model of Al3+ superoxide species including explicit first and second solvation spheres, structures optimized at the B3LYP/6-31++G(d,p) level of theory. From Mujika, Ruiperez, Infante, Ugalde, Exley and Lopez (2011).

To find out more, please check out the following references:

  1. Exley C (2004) The prooxidant activity of aluminium. Free Radical Biology and Medicine 36, 380-387.
  2. Khan A, Dobson J & Exley C (2006) The redox cycling of iron by Aβ42. Free Radical Biology and Medicine 40, 557-569.
  3. Exley C (2006) Aluminium and iron, but neither copper nor zinc, are key to the precipitation of -sheets of Aβ42 in senile plaque cores in Alzheimer's disease. Journal of Alzheimer's Disease 10, 173-177.
  4. Nicholson S & Exley C (2007) Aluminium: A potential pro-oxidant in sunscreens/sunblocks? Free Radical Biology and Medicine 43, 1216-1217.
  5. Mujika JI, Ruiperez F, Infante I, Ugalde JM, Exley C, Lopez X (2011) Pro-oxidant activity of aluminium: Stabilisation of the aluminium superoxide radical ion. The Journal of Physical Chemistry A 115, 6717-6723.