[Study on fenton-methylene blue spectral analysis method for determining the inhibitory effect of quercetin complexes...

In the present, Fenton-Methylene Blue spectral measurement was established, and the new analytical method was applied successfully to determine the inhibitory effect of quercetin (Que) and its complexes on hydroxyl free radical. Methylene Blue(MB) can capture the *OH produced by Fenton reaction, turning its color from blue to achromatic. Therefore, MB was selected as the indicator of the spectral measure study. The testing conditions optimized were pH 8. 0, H2O2 solution (0. 3%) 0. 50 mL, FeSO4 solution (5 mmol x L-1) 0. 50 mL and MB solution(2. 56 x 10(-5) mol x L(-1) )1.0 mL. The experiment results showed that Que-Zn( II), Que-Cu( II) and Que-Fe( III) complexes held significant effects of scavenging action on *OH radical and were more effective in scavenging *OH than quercetin itself, showing the good cooperative action between quercetin and trace metal elements. The structure-bioactivity relationship of the coordination complexes was also discussed through analyzing the antioxygenic activity of quercetin-metal complexes.