6-Methyl-Nitroarachidonate :a novel esterified nitroalkene which potently Inhibits platelet aggregation and exerts cgmp mediated vascular relaxation

Abstract

Nitro-fatty acids represent endogenously occurring products of oxidant-induced nitration reactions. We have previously synthesized a four isomers mixture of nitroarachidonic acid, a novel anti-inflammatory signaling mediator. Herein, we synthesized, chemically and biologically characterized for a first time an esterified nitroalkene derived from the nitration of methylarachidonate (AAMet): 6-methyl-nitroarachidonate (6-AAMetNO2). Synthesis was performed by AAMet reaction with sodium nitrite in acidic conditions. Analysis by mass spectrometry (positive ion ESI-MS) showed a [M+H]+ ion of m/z 364, characteristic of AAMetNO2. Fragmentation of this ion yielded a daughter ion at m/z 317, corresponding to the neutral loss of the nitro group ([M+HHNO2]+). Furthermore, IR signal at 1378 cm-1 and NMR data confirmed the structure of a 6-nitro positional isomer. This novel esterified nitroalkene showed to be capable of promoting vascular protective actions including: a) the induction of vasorelaxation via endothelium-independent mechanisms, associated with an increase of smooth muscle cells cGMP levels and b) a potent dosedependent inhibition of human platelet aggregation. We postulate that 6-AAMetNO2 could be a potential drug for prevention of vascular and inflammatory diseases, where the presence of the methyl group may increase its pharmacological potential.