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157929 
Journal Article 
Chemical oxidation and DNA damage catalysed by inorganic sunscreen ingredients 
Dunford, R; Salinaro, A; Cai, L; Serpone, N; Horikoshi, S; Hidaka, H; Knowland, J 
1997 
Yes 
FEBS Letters
ISSN: 0014-5793
EISSN: 1873-3468 
EMIC/105543 
418 
1-2 
87-90 
English 
9414101 
WOS:A1997YJ81800020 
Titanium dioxide (TiO2) has been noted (US Federal Register, 43FR38206, 25 August 1978) to be a safe physical sunscreen because it reflects and scatters UVB and UVA in sunlight. However, TiO2 absorbs about 70% of incident UV, and in aqueous environments this leads to the generation of hydroxyl radicals which can initiate oxidations. Using chemical methods, we show that all sunscreen TiO2 samples tested catalyse the photo-oxidation of a representative organic substrate (phenol). We also show that sunlight-illuminated TiO2 catalyses DNA damage both in vitro and in human cells. These results may be relevant to the overall effects of sunscreens. 
Sunscreen; Titanium dioxide; Zinc oxide; DNA damage; Hydroxyl radical