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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Isomerization of Cholecalciferol through Energy Transfer as a Protective Mechanism Against Flavin-Sensitized Photooxidation

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Scurachio, Regina S. [1] ; Santos, Willy G. [1] ; do Nascimento, Eduardo S. P. [1] ; Skibsted, Leif H. ; Cardoso, Daniel R. [1]
Total Authors: 5
[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560470 Sao Carlos - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of Agricultural and Food Chemistry; v. 63, n. 18, p. 4629-4637, MAY 13 2015.
Web of Science Citations: 1

Cholecalciferol, vitamin D-3, was found to isomerize to 5,6-trans-vitamin-D-3 with a quantum yield of 0.15 +/- 0.01 in air-saturated 7/3 tert-butyl alcohol/water (v/v) at 25 degrees C, increasing to 0.32 +/- 0.02 in the absence of oxygen, through quenching of triplet excited state flavin mononucleotide, FMN, rather than becoming oxidized. The quenching was found by laser flash photolysis to have a rate constant of 1.4 x 10(8) L mol(-1) s(-1) in 7/3 tert-butyl alcohol/water (v/v) at 25 degrees C, assigned to energy transfer from (FMN)-F-3{*} to form a reactive vit.D-3 diradical. vit.D-3 forms a 1/1 precomplex with FMN by hydrophobic stacking with Delta H degrees = -36 +/- 7 kJ mol(-1) and Delta S degrees = -4 +/- 3 J mol(-1) K-1, as shown by single photon counting fluorescence spectroscopy and steady-state fluorescence spectroscopy. Both ground-state precomplex formation and excited-state energy transfer seem important for vit.D3 protection against flavin-sensitized photooxidation of nutrients in food and biological systems. (AU)

FAPESP's process: 11/51555-7 - Bread and meat for the future
Grantee:Daniel Rodrigues Cardoso
Support type: Regular Research Grants