Antioxidant β-carotene does not quench singlet oxygen in mammalian cells.

Gabriela N Bosio, Thomas Breitenbach, Julieta Parisi, Miguel Reigosa, Frances H Blaikie, Brian W Pedersen, Elsa F F Silva, Daniel O Mártire, Peter R Ogilby

Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4 (1900), La Plata, Argentina.

Journal of the American Chemical Society 2013 Jan 9

filter terms:

Carotenoids, and β-carotene in particular, are important natural antioxidants. Singlet oxygen, the lowest excited state of molecular oxygen, is an intermediate often involved in natural oxidation reactions. The fact that β-carotene efficiently quenches singlet oxygen in solution-phase systems is invariably invoked when explaining the biological antioxidative properties of β-carotene. We recently developed unique microscope-based time-resolved spectroscopic methods that allow us to directly examine singlet oxygen in mammalian cells. We now demonstrate that intracellular singlet oxygen, produced in a photosensitized process, is in fact not efficiently deactivated by β-carotene. This observation requires a re-evaluation of β-carotene's role as an antioxidant in mammalian systems and now underscores the importance of mechanisms by which β-carotene inhibits radical reactions.

Citation

Gabriela N Bosio, Thomas Breitenbach, Julieta Parisi, Miguel Reigosa, Frances H Blaikie, Brian W Pedersen, Elsa F F Silva, Daniel O Mártire, Peter R Ogilby. Antioxidant β-carotene does not quench singlet oxygen in mammalian cells. Journal of the American Chemical Society. 2013 Jan 9;135(1):272-9