2012 Volume 60 Issue 5 Pages 639-646
The various biological activity of dihydropyrazines(DHPs)due to the radical generation potency has been described in previous papers. Detailed data about radical species generating be mentioned here. The electron spin resonance (ESR) spin-trapping technique revealed that DHPs generate free radical species such as ·OH, ·OOH, ·CHR2 and ·CR3. Oxygen radicals and two carbon-centered radicals were detected as adducts of the spin traps DMPO and DBNBS, respectively. All the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO)- and 3,5-dibromo-4-nitrosobenzenesulfonate (DBNBS)-adducts of compounds DHP-1–8 exhibited approximately the same signal patterns, with various levels of intensity depending on the substituent of the dihydropyrazine ring. The ESR signal intensity of DHPs also increased remarkably upon addition of Cu2+, resulting that the effects of DHPs were enhanced.