Prooxidant actions of carotenoids in biologic systems.

The potential for carotenoids to modulate chronic disease risk is currently under investigation, and renewed interest has been placed on achieving a better understanding of the mechanisms of action of carotenoids in biologic systems. Available data currently show that the antioxidant activity of these compounds may shift into prooxidant activity, depending on the redox potential of the carotenoid molecules as well as on the biologic environment in which they act. The prooxidant potency of these compounds is determined by several factors, including oxygen tension, carotenoid concentration, and interactions with other antioxidants. Prooxidant activity can induce either beneficial or harmful results in biologic systems and influence the development of human chronic diseases.