Quencher singlet oxygen

Di Mascio, R, Kaiser, S., and Sies, H., Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch. Biochem. Biophys., 274, 532, 1989. Cantrell, A. et ah. Singlet oxygen quenching by dietary carotenoids in a model membrane environment. Arch. Biochem. Biophys., 412, 47, 2003. 

Although spironaphthooxazines have excellent lightfastness, they decompose slowly on exposure to sunlight. However, lightfastness can be improved by addition of nickel stabilizers (singlet oxygen quenchers) or hindered amines (antioxidants).86 88... 

The three unsymmetrical carotenoids have also been studied in methanol (Burke 2001) and all are very efficient singlet oxygen quenchers. This may be attributable to the polarity of the molecules. These asymmetrical XANs will possess a permanent dipole and their solvent interaction will... 

Di Mascio, P., S. Kaiser, and H. Sies. 1989. Lycopene as the most efficient biological carotenoid singlet oxygen quencher. Arch Biochem Biophys 274(2) 532-538. 

Di Mascio P., Sandquist A., Devasagayam T., and Sies H. (1992). Assay of lycopene and other carotenoids as singlet oxygen quenchers. Methods Enzymol 213 429 438. 

A similar study of the photooxidation of some spiropyrans and spironaphthox-azines indicates that the spiro and open forms of these dyes are singlet oxygen quenchers and that the colored form does not act as a sensitizer. A mechanism is proposed that involves the formation of a superoxide radical anion by photoinduced electron transfer to oxygen from a merocyanine form of the dye, followed by nucleophilic attack of the radical anion on the radical cation of the dye.174... 

Phenolic antioxidants do not protect fats from oxidation by singlet oxidation (Yasaei et al. 1996). However, the antioxidant ascor-byl palmitate is an effective singlet oxygen quencher (Lee et al. 1997). Carotenoids are widely used as quenchers. Rahmani and Csallany (1998) reported that in the photooxidation of virgin olive oil, pheophytin A functioned as sensitizer, while P-carotene acted as a quencher. 

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