Hemoglobin binding and antioxidant activity in spinal cord neurons: O-methylated isoflavone glycitein as a potential small molecule

Abstract

Scientific community has been mesmerized by the application of bioactive O-methylated isoflavones with neuroprotective effects mediated by their antioxidant and antiapoptotic properties. The small size and planar-based structures allow them to interact with a wide range of biomolecules, such as DNA, lipids, and protein. Therefore, glycitein (C16H12O5), 4′,7-dihydroxy-6-methoxyisoflavone, as a potential antioxidant can interact with blood proteins, especially human hemoglobin (HHb), serving as a one of the main carrier proteins. To analyze this interaction, several spectroscopic techniques as well as molecular docking analysis were used. It was revealed that glycitein can interact with HHb mediated by the formation of hydrophobic forces and main aromatic residues. Also, Y140 (A), Y35 (D), and W37 (D) were displaced to a hydrophobic microenvironment upon interaction of HHb with glycitein. Furthermore, glycitein led to a slight increase in the amount of α-helix of HHb. The antioxidant assays showed that glycitein with a low concentration of 5 µM can mitigate the neurotoxicity induced by lipopolysaccharide (LPS, 100 ng/ml) in cultured spinal cord neurons, through mitigation of lactate dehydrogenase (LDH) release, downregulation of reactive oxygen species (ROS) and malonyldialdehyde (MDA) production, recovery of superoxide dismutase (SOD) and catalase (CAT) activity, and downregulation of caspase-3 protein expression and activity. In conclusion, these data indicated that glycitein with potential pharmacological activities can potentially interact with HHb, which can be of interest for future in vivo studies.