Structural characterization and biological activity evaluation of Magnoflorine alkaloid, a potential anticonvulsant agent

Abstract

Magnoflorine (MGF), an isoquinoline alkaloid, emerges as a quaternary aporphine alkaloid derived from Ltyrosine amino acid, found in families Magnoliaceae plants and it presents important biological activity being noted for its effect on the nervous system. In this work, a deep study of structural, vibrational and electronic properties has been carried out for the MGF. From Potential Energy Surface (PES) scan the most stable conformer of alkaloid was identified and geometrical parameters were determined by Density Functional Theory (DFT) using B3LYP/6–311++G** method. A complete vibrational assignment of the normal modes was theoretical and experimentally achieved from FT-IR and Raman spectroscopies and scaled SQM methodology. Electronic transitions observed in UV–visible spectrum in aqueous medium were identified using TD-DFT methodology, with the π→π* transition being the most probable UV signal. The MEPs, the electric charge distribution along with the HOMO and LUMO frontier orbitals were analyzed and the GAP energy values justified the stability of the molecule in aqueous medium. The molecular electrostatic potential map reveals the most favourable region for electrophilic attack on MGF. Molecular docking was used to analyze the anxiolytic biological activity of the title molecule on the GABAA receptor. The results suggest an intermolecular binding capability of MFG toward bothintracellular and extracellular domains of GABAA receptor, and the extracellular domain presents a higher affinity by alkaloid. Finally, the biological study infers that MGF could be used as a potential anxiolytic compound.