Lipofuscin is a photoinducible free radical generator.

Despite the association between high concentrations of the age pigment lipofuscin and various age-related pathologies, there is contention as to whether or not the intracellular accumulation of such granules has an adverse effect on cell function. In this paper, we present evidence to indicate that lipofuscin is a photoinducible free radical generator. White light irradiation of lipofuscin granules resulted in the production of superoxide anions, their rate of production increasing with increased light intensity. This effect appeared to be maximal in the blue light region of the spectrum. We speculate that lipofuscin could be detrimental to bodily functions through free radical generation initiated either by light or interaction with endogenous free radicals.