Premium
Radical Protection by Sunscreens in the Infrared Spectral Range
Author(s) -
Meinke Martina C.,
Haag Stefan F.,
Schanzer Sabine,
Groth Norbert,
Gersonde Ingo,
Lademann Jürgen
Publication year - 2010
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2010.00838.x
Subject(s) - radical , photochemistry , chemistry , infrared , absorption (acoustics) , irradiation , electron paramagnetic resonance , spectroscopy , radiation , electron paramagnetic resonance spectroscopy , materials science , optics , organic chemistry , nuclear magnetic resonance , quantum mechanics , nuclear physics , composite material , physics
One essential reason for skin ageing is the formation of free radicals by excessive or unprotected sun exposure. Recently, free radical generation in skin has been shown to appear not only after irradiation in the UV wavelength range but also in the infrared (IR) spectral range. Sunscreens are known to protect against radicals generated by UV radiation; however, no data exist for those generated by IR radiation. This paper has investigated four different, commercially available sunscreens and one COLIPA standard with regard to radical formation in the skin after IR irradiation, using electron paramagnetic resonance spectroscopy. The use of sunscreens has led to reduced amounts of radicals compared to untreated skin. Furthermore, absorption and scattering properties and the radical protection factor of the formulations were determined to investigate their influence on the radical protection of the skin. None of these formulations contained an optical absorber in the IR range. The protection efficiency of the sunscreens was shown as being induced by the high scattering properties of the sunscreens, as well as the antioxidants contained in the formulations.