Synthesis and anti-nociceptive, anti-inflammatory activities of new aroyl propionic acid derivatives including N-acylhydrazone motif

In the present study, new 4-[4-[2-(2-(4-substituted benzylidene)hydrazinyl)-2-oxoethoxy]phenyl]-4-oxobutanoic acid derivatives were synthesized, and their anti-nociceptive and anti-inflammatory activities were investigated. In the synthesis of the compounds, 4-[4-(2-ethoxy-2-oxoethoxy)phenyl]-4-oxobutanoic acid molecule was used as starting material. The intermediate hydrazide compound (1) was reacted with appropriate aromatic aldehydes to obtain final hydrazone compounds (2a-i). All final compounds are well characterized by IR, H-1 NMR, C-13 NMR, and MS spectroscopic data. Hot-plate and tail-clip tests, measuring centrally organized responses to a nociceptive stimulus, were performed in order to examine anti-nociceptive potentials of the compounds (50 mg/kg). In addition, peripherally mediated anti-nociceptive effect was assessed by acetic acid-induced writhing tests. Further, carrageenan-induced paw edema method was used in order to evaluate the anti-inflammatory activity potential of the compounds. Motor coordination of the animals was examined in a Rota-rod apparatus. The obtained data indicated that compounds 2a, 2b, 2c, 2d, 2e, 2f decreased the number of acetic acid-induced writhing behaviors comparable with diclofenac sodium (10 mg/kg). The same compounds significantly decreased the paw swelling rate (%) of the mice with respect to the control values. These results indicated that compounds 2a, 2b, 2c, 2d, 2e, and 2f have peripherally mediated anti-nociceptive and anti-inflammatory activities. On the other hand, none of the tested compounds changed the reaction time of mice in hot-plate or tail-clip tests indicating that neither supraspinal nor spinal pathways were affected. The observed effect seems to be specific, since Rota-rod tests did not point out any motor impairment induced by the test compounds.