A Preliminary Antidepressant Assessment of a Novel Piperoyl Amide (Y3) Isolated and Elucidated from Piper nigrum Drupes Extract, Justifying Interaction Over MAO-A enzyme: An in vivo, in vitro and Molecular Docking Approach

Abstract

This research aims to confirm the preliminary antidepressant activity of a newly discovered piperoyl amide (Y3) obtained from the extract of Piper nigrum (P. nigrum) drupes, through the inhibition of MAO-A enzyme. Column chromatography was employed for isolation and purification of Novel piperoyl-alkyl amide (Y3) which was eluted in a solvent mixture of Chloroform-Methanol (97:3). Structure elucidation was performed by implying spectroscopic techniques. Invitro in-comparison MAO activity assessment was performed between Y3 and piperine further confirmed by Molecular docking via Auto Dock Tools 1.5.6, Vina, and PyMOL. Invivo antidepressant activity was evaluated by the Despair Test in albino mice. Novel piperoyl-alkyl amide (Y3) was isolated and purified by column chromatography and elucidated spectroscopically. The antidepressant activity of Y3 at 10 and 20 mg/kg doses shown a significant decrease in immobility-time (IT) in contrast to stressed-control group at 107.0±7.6 sec (P<0.05) and 96.0±7.6 sec (P<0.01), respectively. Y3 shown a decent MAO-A inhibitory activity but lower than piperine showing IC50=20.24 µM, Vmax=1.375±0.3 nM/min/mg, Km=1.379×10-16 µM with a stronger interaction and better affinity (-12.6 kcal/mol) towards the active-site of MAO-A. Y3 was isolated and elucidated as (12E,14E)-15-(benzo[d] [1,3] dioxol-5-yl)-N-ethylpentadeca-12,14-dienamide. It proved a good antidepressant at 10 and 20 mg/kg doses. Molecular docking over MAO-A and QSAR studies depicted a better affinity score of Y3 than Piperine. Keywords: Piperoyl amide, Structure elucidation, antidepressant activity, molecular modeling, Piperine