Abilities of Antioxidants to Eliminate the Peroxyl Radical Derived from 2,2%26apos;-Azobis(2-Amidinopropane) Dihydrochloride (AAPH)

作者：Nakajima Akira^*; Masuda Yukari; Matsuda Emiko; Tajima Kunihiko; Sameshima Hiroshi; Ikenoue Tsuyomu

来源：Applied Magnetic Resonance, 2013, 44(9): 997-1005.

DOI：10.1007/s00723-013-0463-9

Electron spin resonance (ESR) of 5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide (CYPMPO) spin adducts of free radicals derived from the UV irradiation of 2,2%26apos;-azobis(2-amidinopropane) dihydrochloride (AAPH) under rapid scanning condition was examined. The ESR signal obtained was the superposition of two spectra, the spin adduct of the alkoxyl radical [CYPMPO-ORa, Ra = C(CH3)(2)-C(+NH2Cl-)NH2] and the peroxyl radical (CYPMPO-OORa). The decay rate of CYPMPO-OORa was 8,400 times that of CYPMPO-ORa. The order of the k (SB)/k (ST) values (the slope of the Stern-Volmer%26apos;s plot) for the peroxyl radical (RaOO center dot) was l-ascorbic acid %26gt; caffeic acid %26gt; rutin similar to Trolox similar to (+)-catechin similar to glutathione (reduced), which was almost the same order as that for the alkoxyl radical (RaO center dot). Though the k (SB)/k (ST) value of each antioxidant for the peroxyl radical was about half of that for the alkoxyl radical, the ratios of the values of antioxidants to that of trolox (the relative ORAC values) were almost the same between the peroxyl and alkoxyl radicals. The relative oxygen radical absorbance capacity (ORAC) values of polyphenols estimated by the ORAC-ESR assay using both peroxyl and alkoxyl radicals were smaller than those by the ORAC-FL assay.

• 出版日期2013-9