Oxidation of naringenin by gamma-radiation

The reaction of (OH)-O-center dot with naringenin (4',5,7-trihydroxyflavanone) in the presence of air induced the formation of the hydroxylation product eriodictyol (3',4',5,7-tetrahydroxyflavanone). Its yield was dependent on pH. The initial degradation yield of naringenin was G(i)(-Nar) = (2.5+/-0.2) x 10(-7) mol dm(-3) J(-1). For the reaction with (OH)-O-center dot, a rate constant k ((OH)-O-center dot + naringenin) = (7.2 +/- 0.7) x 10(9) M-1 s(-1) was determined. In the presence of N2O and NaN3/N2O, no eriodyctiol was formed. Apigenin (4',5,7-trihydroxyflavon) was detected as decay product of the naringenin phenoxyl radicals. In Ar-saturated solutions, naringenin exhibited a pronounced radiation resistance, G(-naringenin) similar to 0.3 x 10(-7) mol dm(-3) j(-1). (C) 2007 Elsevier Ltd. All rights reserved.