Structural analysis of the interaction between free, glycated and fructated hemoglobin with propolis nanoparticles: A spectroscopic study

Abstract

Non enzymatic Glycation is the main causes of diabetic complications. Propolis is a natural product of different plant exudates and buds which has different biological properties such as anti-hyperglycemia. In attention to better performance of nanoparticles in treatment, we synthesized propolis nanoparticles (PNP) and analyzed their physicochemical properties by dynamic light scattering (DLS), scanning electron microscopy (SEM), Zeta potential and FTIR analyses. Then, the structural changes of human hemoglobin (Hb), in three different forms of free, glycated and fructated Hb upon interaction with PNP at two temperatures of 25 and 37°C were investigated using fluorescence and far-UV circular dichoroism (CD) spectroscopic techniques. The size distribution of PNP was less than 100nm. Fluorescence results indicated that PNP have a strong ability in quenching the intrinsic fluorescence of different forms of Hb. The binding constants, number of binding sites and thermodynamic parameters of these interactions were calculated and compare to each other. The Gibbs free energy values for glycated and fructated Hb with PNP were calculated-1635 and 1065J/mol, respectively at 25°C which indicates that interaction of Hb with PNP is more favorable than interaction of GHb with PNP. CD spectra indicated that PNP lead to no significant changes in the secondary structure of different types of Hb. So, PNP as a natural product, due to antioxidant properties and lack of toxicity, can be used in the drug delivery system.