Knak, Alena and Regensburger, Johannes and Maisch, Tim and Baeumler, Wolfgang (2014) Exposure of vitamins to UVB and UVA radiation generates singlet oxygen. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, 13 (5). pp. 820-829. ISSN 1474-905X, 1474-9092
Full text not available from this repository. (Request a copy)Abstract
Deleterious effects of UV radiation in tissue are usually attributed to different mechanisms. Absorption of UVB radiation in cell constituents like DNA causes photochemical reactions. Absorption of UVA radiation in endogenous photosensitizers like vitamins generates singlet oxygen via photosensitized reactions. We investigated two further mechanisms that might be involved in UV mediated cell tissue damage. Firstly, UVB radiation and vitamins also generate singlet oxygen. Secondly, UVB radiation may change the chemical structure of vitamins that may change the role of such endogenous photosensitizers in UVA mediated mechanisms. Vitamins were irradiated in solution using monochromatic UVB (308 nm) or UVA (330, 355, or 370 nm) radiation. Singlet oxygen was directly detected and quantified by its luminescence at 1270 nm. All investigated molecules generated singlet oxygen with a quantum yield ranging from 0.007 (vitamin D-3) to 0.64 (nicotinamide) independent of the excitation wavelength. Moreover, pre-irradiation of vitamins with UVB changed their absorption in the UVB and UVA spectral range. Subsequently, molecules such as vitamin E and vitamin K-1, which normally exhibit no singlet oxygen generation in the UVA, now produce singlet oxygen when exposed to UVA at 355 nm. This interplay of different UV sources is inevitable when applying serial or parallel irradiation with UVA and UVB in experiments in vitro. These results should be of particular importance for parallel irradiation with UVA and UVB in vivo, e. g. when exposing the skin to solar radiation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | HUMAN-SKIN; ENDOGENOUS PHOTOSENSITIZERS; MOLECULAR-OXYGEN; ULTRAVIOLET; IRRADIATION; LUMINESCENCE; DNA; PHOTODEGRADATION; EXPRESSION; MECHANISM; |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Dermatologie und Venerologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 29 Nov 2019 10:36 |
| Last Modified: | 29 Nov 2019 10:36 |
| URI: | https://pred.uni-regensburg.de/id/eprint/11009 |
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