Synthesis and anthelmintic activity of aminochalcones against multiresistant Haemonchus contortus

Síntese e atividade anti-helmíntica de aminochalconas contra Haemonchus contortus multiresistente

The objective of this study was to synthesize and evaluate the in vitro activity of aminochalcones against Haemonchus contortus eggs and adults. Aminochalcones 1 and 2 were synthesized using Claisen–Schmidt condensation and characterized using Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry. The activity of both aminochalcones was assessed in the egg hatch test and that of aminochalcone 1 was further evaluated in the adult worm motility test using multiresistant H. contortus. The chemical structures of the synthesized compounds were confirmed, and changes induced in eggs and adults were assessed using scanning electron microscopy (SEM). Aminochalcones 1 and 2 inhibited larvae hatching by 98.70 and 99.89%, respectively, at concentrations of 0.25 and 1 mg/mL. SEM images revealed structural and morphological changes in eggs treated with both compounds. After 12 h of exposure to aminochalcone 1 (1.25 mg/mL), all adult nematodes were immobile, and wrinkling of the cuticle was observed. These findings indicate the ovicidal effect of aminochalcones and the inhibition of worm motility by aminochalcone 1. Our preliminary study demonstrated, for the first time, the anthelmintic activity of this class of compounds against gastrointestinal nematodes of small ruminants and suggest further anthelmintic evaluation.

Keywords:
Small ruminants; active compounds; structural modifications; antiparasitic effect; gastrointestinal nematodes