Characterization of the activity of L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl-hydrogen phosphate] potassium salt in hydroxyl radical elimination

The effect of L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-( 4,8,12- trimethyltridecyl)-2H-1-benzopyran-6-yl-hydrogen phosphate] potassium salt (EPC-K-1) on hydroxyl radical(. OH) elimination was studied using electron spin resonance (ESR) and spectrophotometric experiments. The addition of EFC-K-t and . OH scavengers eliminated the . OH generated from Cu2+/H2O2, Fe2+/H2O2 and H2O2/UV-irradiation reaction systems. However, in competitive reactions using different concentrations of a spin-trap agent, the addition of the . OH scavenger altered the IC50 values, whereas the addition of EPC-K-1 and a metal chelater did not change the value in the Cu2+/H2O2 and Fe2+/H2O2 reaction systems. The addition of EPC-K-1 and metal chelater changed the ESR signal for free Cu2+. The spectrophotometric experiments confirmed that the addition of EPC-K-1 and metal chelater altered the absorption spectra due to CuCl2 and FeSO4, whereas the . OH scavenger did nut alter the spectra. Therefore, it was demonstrated that EPC-K-1 has the ability both to scavenge . OH directly and to inhibit the generation of . OH by the chelation of Cu2+ and Fe2+.