Synthesis and biochemical applications of a solid cyclic nitrone spin trap: A relatively superior trap for detecting superoxide anions and glutathiylradicals

A novel cyclic nitrone spin trap, 5-tert-butoxycarbonyl 5-methyl-1-pyrrolin e N-oxide (BMPO) as a pure white solid has been synthesized for the first t ime. BMPO offers several advantages over the existing spin traps in the det ection and characterization of thiyl radicals, hydroxyl radicals, and super oxide anions in biological systems. The corresponding BMPO adducts exhibit distinct and characteristic electron spin resonance (ESR) spectral patterns . Unlike the 5,5-dimethyl-1-pyrroline N-oxide (DMPO)-derived superoxide add uct, the BMPO superoxide adduct does not non-enzymatically decompose to the BMPO hydroxyl adduct. This feature is clearly perceived as a definite adva ntage of BMPO in its biological applications. In addition, the ESR spectrum of the BMPO glutathionyl adduct (BMPO/*SG) does not fully overlap with the spectrum of its hydroxyl adduct. This spectral feature is again distinctly different from that of DMPO because the ESR spectral lines of DMPO glutath ionyl and hydroxyl radical adducts largely overlap. Finally, the ESR spectr a of BMPO-derived adducts exhibit a much higher signal-to-noise ratio in bi ological systems. These favorable chemical and spectroscopic features make BMPO ideal for the detection of superoxide anions, hydroxyl and thiyl radic als in biochemical oxidation and reduction. (C) 2001 Elsevier Science Inc.