5-Diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO): a new phosphorylated nitrone for the efficient In Vitro and In Vivo spin trapping of oxygen-centred radicals

Abstract

5-Diethoxyphosphoryl-5-methyl-1 -pyrroline N-oxide (DEPMPO), a newly synthesized spin trap, is used for the in vitro spin trapping of hydroxyl and superoxide radicals, and though the spin trapping rates are close to those reported for 5,5-dimethyl-1 -pyrroline N-oxide (DMPO), the DEPMPO-superoxide spin adduct is significantly more persistent than its DMPO analogue, a difference which allows the detection of superoxide during the reperfusion of ischaemic isolated rat hearts.

The Role of Tetrahydrobiopterin in the Regulation of Neuronal Nitric-oxide Synthase-generated Superoxide

“…First, the rate constant for the reaction of BMPO with O 2 . exceeded that of DMPO, which had been reported to be 15 M Ϫ1 s Ϫ1 (41), and it was slightly slower than that found for DEPMPO at 90 M Ϫ1 s Ϫ1 (42). Second, the half-life of BMPO-OOH was considerably greater than for that of DMPO-OOH at 53 s (43) and in the same range as that for DEPMPO-OOH at 18 min (44).…”

Reexamination of the mechanism of hydroxyl radical adducts formed from the reaction between familial amyotrophic lateral sclerosis-associated Cu,Zn superoxide dismutase mutants and H 2 O 2

“…1B). Based on the literature data (28,29), this spectrum (a P ϭ 47.3 G, a H ϭ 13.2 G, and a N ϭ 14.0 G) was assigned to the DEPMPO-hydroxyl adduct (DEPMPO͞ ⅐ OH). Formation of this spectrum was absolutely dependent on all of the components.…”

“…e-mail: balarama@ mcw.edu. methyl-1-pyrroline N-oxide (DEPMPO) (28)(29)(30) (30). The bicarbonate͞CO 2 buffer solutions were prepared by treating with Chelex 100 resin (Bio-Rad) to remove trace polyvalent metal ions.…”

Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps

“…2). The signals of the superoxide adducts were simulated using the program of Rockenbauer and Korecz [38] using the hyperfine coupling constants (A P , A N , A H , A H ) given in Supplementary Table S1 and were in accordance with those described for DEPMPO-OOH and DIPPMPO-OOH in the literature [15,16] . In phosphate buffer 0.1 M, pH 7.4, the ESR signals of all the superoxide adducts under study spontaneously decayed to diamagnetic species with negligible formation of hydroxyl radical adduct (5-10%).…”

“…Several DMPO analogues bearing an alkoxycarbonyl (e.g. EMPO [13] , BMPO [14] ) or dialkoxyphosphoryl substituent at position 5 (DEPMPO [15] , or DIPPMPO [16] ) are now available, and offer some advantages as their superoxide adducts exhibit longer half-lives in phosphate buffer and do not spontaneously decompose to the corresponding hydroxyl adducts. The stability of their superoxide adducts in vivo or in the presence of biological material remains low and these adducts are easily transformed to diamagnetic compounds.…”