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Changes in ultraviolet absorbance and hence in protective efficacy against lipid peroxidation of organic sunscreens after UVA irradiation.
J Photochem Photobiol B. 2006 Mar 01; 82(3):204-13.JP

Abstract

Owing to the spectral distribution of solar UV, the UVA component of sunlight is now believed to be the main cause of photoaging and photocarcinogenesis and is much more effective than UVB in inducing peroxidative damage. Consequently, most skin care cosmetic products now include UVA filters in their formulations along with UVB filters. These modern sunscreens should provide and maintain their initial absorbance, hence protection, throughout the entire period of exposure to sunlight. However, not all UVA and UVB filters are sufficiently photostable. In this study, we examine the correlation between the photochemical degradation of sunscreen agents under UVA irradiation, with particular reference to the UVA-absorber 4-tert-butyl-4'-methoxydibenzoylmethane, alone and in combination with other organic UV filters (2-ethylhexyl 4 methoxycinnamate and 2-ethylhexyl 2-cyano-3,3-diphenylacrylate) and their ability to prevent UVA-induced lipid peroxidation. Since antioxidants are also added to formulations to deactivate free radicals generated during UVA exposure, vitamin E and the synthetic antioxidant, bis(2,2,6,6-tetramethyl-1-oxyl-piperidine-4-yl)sebacate, a nitroxide derivative, were also included in this study. By using simple in vitro tests, the results show that a decrease in spectral absorbance of the UV filters correlates in most cases with increased UVA-induced lipid peroxidation; this depends on the specific UV absorber analysed and also on whether they are alone or in combination. Furthermore, the combined presence or absence of antioxidants has a profound effect on this oxidative event. In particular, the nitroxide appears to be a more efficient photo-antioxidant than vitamin E. Similar experiments were also performed under natural sunlight and the results obtained did not differ substantially from those performed under UVA. The results presented and discussed in this work may help in understanding the effects of UVA/UVB absorbers and antioxidants upon the level of UV-induced ROS generated under UVA exposure and in natural sunlight which could be relevant for improving the photoprotection and efficacy of skin care cosmetic formulations.

Authors+Show Affiliations

Istituto di Biochimica, Via Ranieri, Università Politecnica delle Marche, I-60131 Ancona, Italy. e.damiani@univpm.itNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16442301

Citation

Damiani, Elisabetta, et al. "Changes in Ultraviolet Absorbance and Hence in Protective Efficacy Against Lipid Peroxidation of Organic Sunscreens After UVA Irradiation." Journal of Photochemistry and Photobiology. B, Biology, vol. 82, no. 3, 2006, pp. 204-13.
Damiani E, Rosati L, Castagna R, et al. Changes in ultraviolet absorbance and hence in protective efficacy against lipid peroxidation of organic sunscreens after UVA irradiation. J Photochem Photobiol B. 2006;82(3):204-13.
Damiani, E., Rosati, L., Castagna, R., Carloni, P., & Greci, L. (2006). Changes in ultraviolet absorbance and hence in protective efficacy against lipid peroxidation of organic sunscreens after UVA irradiation. Journal of Photochemistry and Photobiology. B, Biology, 82(3), 204-13.
Damiani E, et al. Changes in Ultraviolet Absorbance and Hence in Protective Efficacy Against Lipid Peroxidation of Organic Sunscreens After UVA Irradiation. J Photochem Photobiol B. 2006 Mar 1;82(3):204-13. PubMed PMID: 16442301.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Changes in ultraviolet absorbance and hence in protective efficacy against lipid peroxidation of organic sunscreens after UVA irradiation. AU - Damiani,Elisabetta, AU - Rosati,Luca, AU - Castagna,Riccardo, AU - Carloni,Patricia, AU - Greci,Lucedio, Y1 - 2006/01/25/ PY - 2005/01/19/received PY - 2005/03/29/accepted PY - 2006/1/31/pubmed PY - 2006/6/14/medline PY - 2006/1/31/entrez SP - 204 EP - 13 JF - Journal of photochemistry and photobiology. B, Biology JO - J Photochem Photobiol B VL - 82 IS - 3 N2 - Owing to the spectral distribution of solar UV, the UVA component of sunlight is now believed to be the main cause of photoaging and photocarcinogenesis and is much more effective than UVB in inducing peroxidative damage. Consequently, most skin care cosmetic products now include UVA filters in their formulations along with UVB filters. These modern sunscreens should provide and maintain their initial absorbance, hence protection, throughout the entire period of exposure to sunlight. However, not all UVA and UVB filters are sufficiently photostable. In this study, we examine the correlation between the photochemical degradation of sunscreen agents under UVA irradiation, with particular reference to the UVA-absorber 4-tert-butyl-4'-methoxydibenzoylmethane, alone and in combination with other organic UV filters (2-ethylhexyl 4 methoxycinnamate and 2-ethylhexyl 2-cyano-3,3-diphenylacrylate) and their ability to prevent UVA-induced lipid peroxidation. Since antioxidants are also added to formulations to deactivate free radicals generated during UVA exposure, vitamin E and the synthetic antioxidant, bis(2,2,6,6-tetramethyl-1-oxyl-piperidine-4-yl)sebacate, a nitroxide derivative, were also included in this study. By using simple in vitro tests, the results show that a decrease in spectral absorbance of the UV filters correlates in most cases with increased UVA-induced lipid peroxidation; this depends on the specific UV absorber analysed and also on whether they are alone or in combination. Furthermore, the combined presence or absence of antioxidants has a profound effect on this oxidative event. In particular, the nitroxide appears to be a more efficient photo-antioxidant than vitamin E. Similar experiments were also performed under natural sunlight and the results obtained did not differ substantially from those performed under UVA. The results presented and discussed in this work may help in understanding the effects of UVA/UVB absorbers and antioxidants upon the level of UV-induced ROS generated under UVA exposure and in natural sunlight which could be relevant for improving the photoprotection and efficacy of skin care cosmetic formulations. SN - 1011-1344 UR - https://www.unboundmedicine.com/medline/citation/16442301/Changes_in_ultraviolet_absorbance_and_hence_in_protective_efficacy_against_lipid_peroxidation_of_organic_sunscreens_after_UVA_irradiation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1011-1344(05)00238-1 DB - PRIME DP - Unbound Medicine ER -