Abstract: The photoinduced redox reaction between hypocrellin A and reduced glutathione (GluSH) was investigated.Hypocrellin A, a derivative of 3, 10-dihydroxy-4, 9-perylenequinone, undergoes light-induced one-electron reduction in the presence of GluSH as electron donor.Depending on the PH of the medium the product can be semiquinone radical or dihydrohypoc-rellin A.The quantum yield of one-electron reduction of hypocrellin A increased with increasing pH.The hypocrellin A sensitized oxidation of GluSH proceeds through the mixed mechanism of Foote Type Ⅰ and Type Ⅱ in aerated solution, and the hydroxy radical generated through Fenton reaction was also detected by ESR.Hypocrellin A sensitized oxidation of GluSH in aerated lipsome solution follows the Foote Type Ⅱ mechanism, which was verified by dynamic measurements.

Key words: hypocrellin A, reduced glutuhione, photoinduced electron transfer, pho-tooxidation, semiquinone radical, active oxygen