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Immediate pigment darkening: its evolutionary roles may include protection against folate photosensitization
Author(s) -
Moan Johan,
Nielsen Kristian Pagh,
Juzeniene Asta
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.11-195859
Subject(s) - photoprotection , photodegradation , endogeny , pigment , human skin , chemistry , absorption (acoustics) , biology , biochemistry , genetics , photosynthesis , materials science , photocatalysis , organic chemistry , catalysis , composite material
The evolution of dark human skin colors in tropical areas is possibly related to photoprotection of folates. However, natural folates absorb mainly UVB radiation, and too little UVB can penetrate down to folates in dermal vessels to cause serious damage. However, endogenous photosensitizers, like riboflavin and uroporphyrin, absorbing UVA and visible light, can cause photosensitization of folates. Immediate pigment darkening (IPD), generated by UVA, has an absorption spectrum covering those of the endogenous photosensitizers. IPD is most prominent for darker skin types, which were typical for populations living under tropical solar fluences. We here propose that the biological role of IPD is protection of folates against photodegradation, which would be of large evolutionary importance for early hominids.— Moan, J., Nielsen, K. P., Juzeniene, A. Immediate pigment darkening: its evolutionary roles may include protection against folate photosensitization. FASEB J. 26, 971‐975 (2012). www.fasebj.org