Synthesis, hypoglycemic activity and molecular modeling studies of pyrazole-3-carbohydrazides designed by a CoMFA model

• Novel pyrazole derivatives were designed and synthesized by a predictive CoMFA model.
• The compounds show important hypoglycemic activity superior to that of glibenclamide.
• A homology model of CB1 was constructed using a β1-adrenergic receptor as a template.
• Docking shows the compounds acting in a similar way to that proposed for rimonabant.
• Stable ligand–receptor complexes were formed in the dynamics simulations carried out.

Diabetes and obesity are two universal health problems that constitute a research objective of several groups due to the lack of efficient and safe drug treatment. In this sense, cannabinoid receptor 1 (CB1) has attracted interest because of its role in food intake and metabolic balance, two targets in the control of metabolic syndrome. In this work, novel 1,5-diaryl pyrazole derivatives were synthesized in accordance with the pKi prediction of a previously reported CoMFA model by our group. To further investigate the biological activity of these compounds in metabolic disorders, their hypoglycemic activity in an in vivo model was tested. Interestingly, a high degree of correlation was observed between the predicted pKi and hypoglycemic effect 7 h after administration. Compounds 4, 9 and 13 showed the most significant plasma glucose reduction with decreases of 60%, 64% and 60% respectively. This result not only surpasses the activity of the lead rimonabant, but also that of the reference drug glibenclamide. Moreover, PASS prediction and molecular docking in an excellent validated homology model of CB1 suggest that these compounds would probably act as CB1 antagonists/inverse agonists and therefore, anti-obesity agents. The ligand–receptor complexes demonstrate that 1,5-diaryl pyrazole derivatives bind to the proposed binding site where a hydrophobic moiety interacts with the phenyl rings in the pyrazole nucleus and Lys192 forms a hydrogen bond with the oxygen of the carbonyl group. Dynamics simulations were also carried out to study the stability of the ligand–receptor complexes where the most active compounds showed smaller ΔG values and more hydrogen bonds throughout the simulation. These compounds are considered useful leads for further optimization in the treatment of such metabolic illnesses.

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