Reactivity of 2,2-Diphenyl-1-picrylhydrazyl Radical Solubilized in Water by β-Cyclodextrin and Its Derivatives

Recently, we have reported the solubilization of 2,2-diphyenyl-1-picrylhydrazyl radical (DPPH•) in water using β-cyclodextrin (β-CD). However, the yield of the β-cyclodextrin-solubilized DPPH• (DPPH•/β-CD) is less than 1% due to the poor solubility of β-CD in water.In this study, the β-CD derivatives, such as 2,6-di-O-methyl-β-CD (DM-β-CD), were used instead of β-CD to improve the solubility of DPPH• in water. The scavenging rate constants of DPPH•/DM-β-CD by the water soluble antioxidants ware about half as compared with those of DPPH•/β-CD