A method was developed to treat the result from an antioxidant trapping radicals including 2,2＇-azinobis （3-ethylbenzothiazoline-6-sulfonate） cationic radieal（ABTS＋＇）, 2,2＇-diphenyl-l-picrylhydrazyl radical（D...A method was developed to treat the result from an antioxidant trapping radicals including 2,2＇-azinobis （3-ethylbenzothiazoline-6-sulfonate） cationic radieal（ABTS＋＇）, 2,2＇-diphenyl-l-picrylhydrazyl radical（DPPH）, and galvinoxyl radical. In the presence of a certain concentration of an antioxidant, the decrease of the concentration of a kind of radicals follows the second order exponential function with the increase of the reaction time（t）, v＆., [radical]=Ae-t/a＋Be rib＋c, the derivation operation of which obtains the differential style, -d[radical]/dt= （A/a）e t/a＋（B/b）e-t/b, revealing the relationship between the reaction rate（r=-d[radical]/dt） and the reaction time（t）. Thus, the reaction rate at the beginning of the reaction@0） can be calculated by assigning t=-0 in the equation of -d[radical]/dt-t. Based on the concept of the reaction rate, r=k[radical][antioxidant], the rate constant（k） can be calculated based on r0 and the initial concentrations of radical and antioxidant, k=-r0/（[radieal]o[antioxidant]0）. The k means the rate of a fresh antioxidant molecule to trap a fresh radical. This method was used to treat the interactions of ABTS＋＇, DPPH, and galvinoxyl radicals with three homoisoflavonoids, four pyrazoles, and three ferrocenyl Schiff bases. It was found that ferrocenyl group is beneficial for antioxidants to reduce ABTS＋＇, and ortho-hydroxyl group is beneficial for antioxidants to donate hydrogen atom in phenolic hydroxyl group to DPPH and galvinoxyl radicals.展开更多
文摘A method was developed to treat the result from an antioxidant trapping radicals including 2,2＇-azinobis （3-ethylbenzothiazoline-6-sulfonate） cationic radieal（ABTS＋＇）, 2,2＇-diphenyl-l-picrylhydrazyl radical（DPPH）, and galvinoxyl radical. In the presence of a certain concentration of an antioxidant, the decrease of the concentration of a kind of radicals follows the second order exponential function with the increase of the reaction time（t）, v＆., [radical]=Ae-t/a＋Be rib＋c, the derivation operation of which obtains the differential style, -d[radical]/dt= （A/a）e t/a＋（B/b）e-t/b, revealing the relationship between the reaction rate（r=-d[radical]/dt） and the reaction time（t）. Thus, the reaction rate at the beginning of the reaction@0） can be calculated by assigning t=-0 in the equation of -d[radical]/dt-t. Based on the concept of the reaction rate, r=k[radical][antioxidant], the rate constant（k） can be calculated based on r0 and the initial concentrations of radical and antioxidant, k=-r0/（[radieal]o[antioxidant]0）. The k means the rate of a fresh antioxidant molecule to trap a fresh radical. This method was used to treat the interactions of ABTS＋＇, DPPH, and galvinoxyl radicals with three homoisoflavonoids, four pyrazoles, and three ferrocenyl Schiff bases. It was found that ferrocenyl group is beneficial for antioxidants to reduce ABTS＋＇, and ortho-hydroxyl group is beneficial for antioxidants to donate hydrogen atom in phenolic hydroxyl group to DPPH and galvinoxyl radicals.
