Unraveling the interaction of an opium poppy alkaloid noscapine ionic liquid with human hemoglobin: Biophysical and computational studies

Abstract

Apart from a wide range of applications, nowadays, Ionic liquids (ILs) are showing their major importance in the field of pharmaceuticals for the development of effective therapeutics. Along with them, proteins are the major targets of a drug and a little alteration in their conformation can lead them to act differently. In the present study, a step has been taken towards the binding of a noscapine (Nos) based ionic liquid [Pip-Nos]OTf with human hemoglobin (Hb), as the blood plasma has a special role in the transport and targeting of a drug. Noscapine, is a phthalideisoquinoline alkaloid, derived from an opium poppy (Papaver Somniferum) having various biological properties. UV–Vis absorption spectroscopy, steady state fluorescence spectroscopy, circular dichroism (CD) and computational studies have been used to study the molecular interaction of [Pip-Nos]OTf with human hemoglobin. UV–Vis spectra showed an increase in absorption intensity with a considerable red (bathochromic) shift on continuous addition of [Pip-Nos]OTf. A static quenching was observed with the formation of ground state complex in fluorescence spectroscopy. CD analysis showed no significant changes in the secondary structure of Hb on the addition of [Pip-Nos]OTf. It was found to bind strongly with hemoglobin in its catalytic groove with a high molecular docking score of −265.47 kJ/mol. Besides, molecular dynamics simulation studies delineate the stable and prolonged binding of [Pip-Nos]OTf to hemoglobin with minimal deviations in deformations plot and covariance matrix statistics. These favorable outcomes of stable binding of [Pip-Nos]OTf with hemoglobin, also depicted certain common spectroscopic and in silico features to the previously reported interaction of this ionic liquid with BSA and conclusively, showed its promising candidature as cancer therapeutics.