Investigation of multiphoton-induced fluorescence from solutions of 5-hydroxytryptophan.

It is reported (J. B. S.

One-electron oxidation of "photo-Fenton" reagents and inhibition of lipid peroxidation.

The "photo-Fenton" reagent, 2-mercaptopyridine N-oxide (MPO), which releases a hydroxyl radical on ultraviolet irradiation, has been found to act as an antioxidant. In the peroxidation of linoleate initiated by a water-soluble azo-initiator, MPO has about one-third the activity of the water-soluble vitamin E analogue Trolox C. In contrast, the oxygen-containing analogue, 2-hydroxypyridine N-oxide (HPO), does not have measurable antioxidant activity in this system.