Introduction: Cyanidinis an anthocyanidin widely distributed in fruits and vegetables with novel antioxidant activity. cyanidin has been implicated in attenuating the development of different major disease including asthma , diabetes ,atherosclerosis and cancer. Human serum albumin is most versatile carrier protein in plasma possessing multiple functions . Human transferrin has a transferrin iron bound receptor it enables ligand bonding to transferrin. The aims of this were investigate determining how cyanidin binding affected HSA - HTF interaction by using different biophysical methods
Methods: Fluorescence spectra excitation wavelength set to 280 ,295and 305 in the presence of increasing concentration of Cya, and the emission wavelength was recorded between 300 nm to 600nm.the synchronous spectra were evaluated through the simultaneous scanning of the excitation and emission monochromators while maintaining a constant wavelength interval (∆λ) between them. In this study ,The ∆λ values were set at 15 nm and 60 nm , which characterize the properties of the Tyr and Trp residues , respectively .RLS spectra were accomplished by simultaneously scanning the excitation and emission monochromators from 220 to 600 with ∆λ=0 nm (slit widths of 5 nm for the excitation and emission )
Results: The interaction between cyanidin and HSA-HTF complex was evaluated through fluorescence quenching of HSA-HTF by increasing different concentration of cyanidin and demonstrated conformational changing. When the between the excitation and the emission wavelength is stabilized at 15nm and 60 nm, The synchronous florescence intensities of HSA-HTF decreased regularly with increasing the concentration of cyanidin ;This demonstrated that TRP and TYR residues play an important role in HSA-HTF system .The enhanced RLS intensity was proportional to the concentration of cyanidin , which suggested complex formation between cyanidin and proteins and interaction has occurred
Conclusion: The complexation between HSA and HTF in the presence of cyanidin have been deciphered in this study by using the different spectroscopic methods .Analysis of the fluorescence data suggested that HSA bound to HTF in the presence of cyanidin through quenching mechanism
Keywords: Cyanidin , human serum albumin , human transferrin , fluorescence spectroscopy