Investigation on the free radical producing effect of hematoporphyrin (a spin trapping study)

Direct evidence was given concerning the free radical production of hematoporphyrin (HP) and its derivative, during illumination, by ESR spectroscopy. A spin trapping measurement was carried out using PBN spin trap for determination of this radical(s). Three different spin-adducts were found. Two of them are likely to be connected to the reactive free radical production of HP.