Probing the Molecular Interactions of Piperidine Alkaloid Lobeline with Ovalbumin: Anti-Aggregation and Anti-Glycation Potential

Lobeline (LOB) is a bioactive alkaloid known for its neuroprotective and cognitive-enhancing properties, particularly in mitigating oxidative stress and inflammation associated with neurodegenerative diseases. While LOB has been studied for its pharmacological roles in CNS disorders, substance abuse treatment, and smoking cessation, its molecular interactions with proteins and potential antiamyloid, antiglycation, and antioxidant properties remain largely unexplored. This study addresses this gap by analyzing LOB interactions with ovalbumin (OVA) through advanced biophysical and computational techniques to elucidate its therapeutic potential and inform drug development. Fluorescence spectroscopy confirmed a static quenching mechanism and binding constant (Kb) of 105 M-1 with a monopreferential binding site in OVA by LOB. Isothermal titration calorimetry (ITC) indicated an exothermic, entropy-driven interaction, while differential scanning calorimetry (DSC) demonstrated LOB-induced stabilization of OVA. Synchronous fluorescence and red edge excitation shift highlighted LOB's effect on Trp and Tyr residues, while circular dichroism (CD) spectroscopy indicated LOB-induced conformational changes in OVA. Molecular modeling (docking and dynamic simulation) corroborated the experimental findings. Turbidity, thioflavin T (ThT), nile red (NR), 8-anilinonaphthalene-1-sulfonic acid (ANS), CD, and morphological studies confirmed OVA fibril formation, and the aggregation was shown to be inhibited by ligand LOB in vitro. Additionally, d-fructose was used to glycate the OVA protein, creating a model to examine the antiglycation and antioxidant effects of LOB. These aspects are essential for advancing targeted drug design and delivery systems, as they provide vital insights into modern biophysical and biochemical research.