Effects of Acylhydrazone Derivatives on Experimental Pulmonary Inflammation by Chemical Sensitization.

Background: Chronic lung diseases are characterized by airway inflammation and remodelling of the lung parenchyma that triggers considerable impairment of respiratory function.

Objective: In this study, two compounds belonging to the N-acylhydrazone class were evaluated, aiming to identify new therapeutic agents for pulmonary inflammatory diseases.

Materials and methods: The acute toxicity of 2-cyano-N'-(3-ethoxy-4-hydroxybenzylidene)- acetohydrazide (JR-12) and N'-benzylidene-2-cyano-3-phenylacrylohydrazide (JR09-Bz) was evaluated. Afterwards, they were tested in models of ovalbumin (OVA)-induced allergic asthma and pleurisy, bleomycin-induced pulmonary fibrosis, in addition to mucolytic activity.

Results and discussion: The compounds did not show toxicity at the dose of 2,000 mg/kg, and no animal died. On OVA-induced pleurisy, animals treated with JR-12 or JR09-Bz at a dose of 10 mg/kg (orally) showed significant inhibition of the leukocyte infiltrate in the bronchoalveolar lavage by 62.5% and 61.5%, respectively, compared to the control group. The compounds JR-12 and JR09-Bz were also active in blocking the allergic asthmatic response triggered by OVA, reducing the leukocyte infiltrate by 73.1% and 69.8%, respectively. Histopathological changes and mast cell migration in treated animals with JR-12 or JR09-Bz were similar to treatment with the reference drugs dexamethasone and montelukast. JR-12 and JR09-Bz also reversed airway remodeling in animals on the bleomycin-induced fibrosis model compared to the control group. Furthermore, it was observed that N-arylhydrazone derivatives showed expectorant and mucolytic activities, increasing mucus secretion by 45.6% and 63.8% for JR-12 and JR09-Bz, respectively.

Conclusion: Together, the results show that JR-12 and JR09-Bz showed promising activity against airway inflammation, as well as low toxicity.