RESUMO
Kinetics and mechanism of vitamin D3 action were investigated in the process of initiated oxidation of various modeling systems in comparison with activity of various antioxidants such as: alpha-tocopherol, dibunol, alpha-tocopheryl quinone, ubiquinone Q10, philloquinone and beta-carotene. Vitamin D3 addition increased initial and maximal rates of oxygen consumption. The length of circuits, value of a kinetic parameter k2/square root k6, describing oxidability of system as a whole was also increased. Cholecalciferol concentrations exceeding 7.5 x 10(-6) M inhibited these processes. Increase of conjugated dienes was proportional to vitamin D3 concentration. Vitamin D3 did not influence kinetics of accumulation of TBA-reactive products. These results may be explained by high lability of cholecalciferol, which may represent an additional source of free radicals.
