水環境中における香辛料刺激成分による一重項酸素消去の評価

抄録

The singlet oxygen (¹O₂) quenching ability of pungent o-methoxyphenols (OMPs) such as capsaicin and zingerone found in spices was evaluated by measuring the time evolution of ¹O₂ phosphorescence. The ¹O₂ quenching rate constants (k_Q) for poorly watersoluble OMPs in aqueous media were estimated using cyclodextrin (CD) as a solubility enhancer. The k_Q values obtained for the tested compounds in aqueous media were 10⁷ ~ 10⁹ M^-1 s^-1, which were 20 ~ 100 times larger than those in ethanol, indicating that the quenching reaction is essentially electrophilic. In aqueous media, addition of CD caused a large decrease in k_Q. This was likely due to a kinetic inhibition effect caused by encapsulation and an increase in viscosity. Dispersion into aqueous media using CD is applicable to antioxidant evaluations of poorly water-soluble compounds even for fast reactions such as ¹O₂ quenching.