Antioxidant β-carotene does not quench singlet oxygen in mammalian cells
- Bosio, Gabriela Natalia
- Breitenbach, Thomas
- Parisi, Julieta Marcia
- Reigosa, Miguel Antonio
- Blaikie, Frances H.
- Pedersen, Brian W.
- Silva, Elsa F. F.
- Martire, Daniel Osvaldo
- Ogilby, Peter R.
DOIAbstract
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...
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