Open AccessMechanism of protection of adenosine from tert-butoxyl radicals and repair of adenosine radicals by α-tocopherol in aqueous solution
Author(s) -
G. Vijayalakshmmi,
M. Adinarayanna,
P. Jayaprrakash Rao
Publication year - 2014
Publication title -
malaysian journal of fundamental and applied sciences
Language(s) - English
Resource type - Journals
ISSN - 2289-599X
DOI - 10.11113/mjfas.v7n1.205
Subject(s) - radical , adenosine , chemistry , photodissociation , tocopherol , reaction rate constant , photochemistry , kinetics , antioxidant , organic chemistry , biochemistry , vitamin e , physics , quantum mechanics
The rates of oxidation of adenosine and α-tocopherol by tert-butoxyl radicals (t-BuO•) were studied spectrophotometrically. Radicals (t-BuO•) were generated by the photolysis of tert-butyl hydroperoxide (t-BuOOH) in presence of tert-butyl alcohol to scavenge •OH radicals. The rates and the quantum yields () of oxidation of α-tocopherol by t-BuO• radicals were determined in the absence and presence of varying concentrations of adenosine. An increase in the concentration of adenosine was found to decrease the rate of oxidation of α-tocopherol, suggesting that adenosine and α-tocopherol competed for t-BuO• radicals. From competition kinetics, the rate constant of α-tocopherol reaction with t-BuO• was calculated to be 7.29 x 108 dm3 mol-1 s-1. The quantum yields expt and cal values suggested that α-tocopherol not only protected adenosine from t-BuO• radicals, but also repaired adenosine radicals, formed by the reaction of adenosine with t-BuO• radicals.