Radical-Scavenging Activity of a Sunscreen Enriched by Antioxidants Providing Protection in the Whole Solar Spectral Range.
OBJECTIVE
The main reason for extrinsic skin aging is the negative action of free radicals. The formation of free radicals in the skin has been associated with ultraviolet (UV) exposure and also to visible (VIS) and near-infrared (NIR) irradiations. The aim of the present study was to evaluate the efficacy of a sunscreen in the whole solar range.


METHODS
The radical-scavenging activity of a sunscreen in the UV, VIS, and NIR ranges was evaluated using electron paramagnetic resonance spectroscopy. Ex vivo penetration profiles were determined using confocal Raman microscopy on porcine ear skin at different time points after application.


RESULTS
Compared to the untreated skin, the sunscreen decreased the skin radical formation in the UV and VIS regions. Additional protection in the VIS and NIR ranges was observed for the sunscreen containing antioxidants (AO). The penetration depth of the cream was less than 11.2 ± 3.0 µm for all time points.


CONCLUSIONS
A sunscreen containing AO improved the photoprotection in the VIS and NIR ranges. The sunscreen was retained in the stratum corneum. Therefore, these results show the possibility of the development of effective and safer sunscreen products.
Laboratory of Cosmetic Technology, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
Carla
C
Souza
Patrícia
P
Maia Campos
Sabine
S
Schanzer
Stephanie
S
Albrecht
Silke B
SB
Lohan
Jürgen
J
Lademann
Maxim E
ME
Darvin
Martina C
MC
Meinke
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects; D013472:Sunlight / Q000009:adverse effects; D013473:Sunscreening Agents / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine; D014466:Ultraviolet Rays / Q000009:adverse effects
D000975:Antioxidants; D016166:Free Radical Scavengers; D005609:Free Radicals; D013473:Sunscreening Agents
Antioxidants; Confocal Raman microscopy; Electron paramagnetic resonance spectroscopy; Radical formation; Skin penetration profile; Sunscreen