[Spectral characterization for capsanthin molecule with in vitro oxidative defense reaction]

The changes of UV-Vis and FTIR spectroscopic properties for capsanthin before and after reaction with exogenous superoxide anion (*O2(-)), hydrogen peroxide (H2O2) and hydroxyl radical (*OH), catalase (CAT), peroxidase (POD) and lipoxygenase (LOX) were explored. The results showed that, the UV-Vis spectral absorption of capsanthin treated with reactive oxygen species had a blue-shift. At the same time, the FTIR spectra changed significantly. The number of FTIR spectral peaks reduced and theFTIR strength weakened for capsanthin molecule treated with *O2(-) and *OH. The characteristic and strong peaks moved to shorter wavelengths when treated with H2O2. And LOX caused breakage of capsanthin molecule and reduction of peak number or groups without carbonyl. Exogenous H2O2 + CAT or H2O2 + POD treatment could not affect the UV-Vis and FTIR spectra significantly. So ROS could cause oxidative degradation of capsanthin and destroy chromophoric groups such as carbon-carbon double bond and carbonyl, then grow colorless alcohols. Hence ROS and LOX should transforms the conjugate system of capsanthin molecules, while CAT and POD could protect the capsanthin.