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Quenching of Singlet Oxygen by a Carotenoid-Cyclodextrin Complex: The Importance of Aggregate Formation
| Content Provider | Scilit |
|---|---|
| Author | Kanofsky, Jeffrey R. Sima, Paul D. |
| Copyright Year | 2009 |
| Description | Journal: Photochemistry and Photobiology The Girard's reagent P derivative of canthaxanthin ((GRP)(2)-canthaxanthin), a dicationic carotenoid, forms a highly water-dispersible complex with (2-hydroxypropyl)-gamma-cyclodextrin. The UV-visible light spectrum of the complex is consistent with some degree of aggregation, but the spectrum is independent of concentration from 7.5 to 750 mum. Stern-Vomer plots for singlet-oxygen quenching by the complex are linear over a concentration range of 0-20 mum. In the presence of 1 mm (2-hydroxypropyl)-gamma-cyclodextrin, the singlet-oxygen quenching constant for the complex is 7.9 +/- 0.9 x 10(8) m(-1)s(-1). This is about an order of magnitude lower than the singlet-oxygen quenching constants for (GRP)(2)-canthaxanthin in various organic solvents. The properties of the complex are also compared with the properties of (GRP)(2)-canthaxanthin solubilized in neat water and in water containing various detergents. The singlet-oxygen quenching constant for (GRP)(2)-canthaxanthin in micelles depends strongly on the specific detergent used, varying from 9.4 x 10(8) m(-1)s(-1) for hexadecyltrimethylammonium bromide (CTAB) to 1.24 +/- 0.4 x 10(10) m(-1)s(-1) for sodium dodecyl sulfate. The small quenching constant in CTAB micelles correlates with spectroscopic evidence for aggregation of the (GRP)(2)-canthaxanthin in this detergent. |
| Related Links | http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.2008.00461.x/pdf |
| Ending Page | 399 |
| Page Count | 9 |
| Starting Page | 391 |
| e-ISSN | 17511097 |
| DOI | 10.1111/j.1751-1097.2008.00461.x |
| Journal | Photochemistry and Photobiology |
| Issue Number | 1 |
| Volume Number | 85 |
| Language | English |
| Publisher | Wiley-Blackwell |
| Publisher Date | 2009-01-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: Photochemistry and Photobiology Biochemistry and Molecular Biology Atomic, Molecular and Chemical Physics Quenching Constant |
| Content Type | Text |
| Resource Type | Article |