[Photochemiluminescent study of the antioxidant activity in biological systems. Mathematical modeling]

The mathematical modeling of the kinetics of riboflavin photo-chemiluminescence (PCL) in the presence of antioxidants, superoxide dismutase and ascorbic acid, has been performed. A specially developed computer program "Kinetic Analyzer" was used for the modeling. The PCL intensity of was taken as directly proportional to the superoxide concentration, because lucigenin had been added to the system. It was found, that the experimental curves of PCL virtually coincide with those calculated in the case of the following set of reactions (reaction rate constants, M-1.s-1 are given in brackets): hv + RH-->R. + .O2- (2,3 x 10(-4) s-1); RH + .O2(-)-->R. + H2O2 (1000); RH-->...(0,005 s-1); .O2- + .O2(-)-->... + phi OTOH (2 x 10(5) M-1 s-1); SOD + .O2(-)-->SOD H2O2 (1 x 10(8)); ASC + .O2(-)-->...(2 x 10(7)). Here RH is, .O2(-)--superoxide, R.--riboflavin radical, SOD--superoxide dismutase, ASC--ascorbate.