HYPOCRELLIN‐A SENSITIZED PHOTOOXIDATION OF BILIRUBIN

Abstract
Abstract— Hypocrellin A (HA) extracted from Hypocrellia batnbusae (b.et Br.) sace, a derivative of 3,10‐dihydroxy‐4,9‐perylenequinone, is a highly effective photosensitizer. Kinetic studies of the HA‐sensitized photooxidation of bilirubin IXα (BR) in different solvents in the presence of various active oxygen quenchers indicate that in aprotic solvents the photooxidation goes via a Type II (1O2) mechanism, whereas in alkaline protic solvents Type I (electron transfer from an excited state of HA to the ground state of oxygen or the BR substrate). Type II and probably free radical reactions may occur simultaneously.