Study of the Interaction of Cinnamaldehyde with Alpha-lactalbumin: Spectroscopic and Molecular Docking Investigation

Cinnamaldehyde is an important compound of the cinnamon essential oil, and it is responsible for the most of the health benefits of cinnamon. Enriching foods such as milk with cinnamaldehyde can lead to greater utilization of cinnamaldehyde properties. In this study, we investigated the interaction of cinnamaldehyde with bovine alpha-lactalbumin. Analyzing the spectrum of alpha-lactalbumin in the presence of different concentrations of cinnamaldehyde by ultraviolet-visible, fluorescence and circular dichroism spectroscopy showed that cinnamaldehyde is capable to bind to alpha-lactalbumin without changing its secondary structure. Conformational change in alphalactalbumin induced by interaction with cinnamaldehyde and the number of binding sites and binding constant were 1.1 and 5.88  105 M-1, respectively. The molecular docking results showed one binding site which most of its interactions are hydrophobic. The ability of cinnamaldehyde to bind to alpha-lactalbumin suggests that alpha-lactalbumin can be used as a suitable vehicle for cinnamaldehyde especially for fortification of milk.