The interaction of isoquinoline alkaloid crebanine with immunoglobulin G and cytotoxic effects toward MCF-7 breast cancer cell line.

In this study, the interaction of crebanine, an isoquinoline alkaloid, with immunoglobulin G (IgG) was evaluated. Subsequently, the anticancer effects of crebanine in MCF-7 breast cancer cells were assessed. The results demonstrate that static quenching plays a key role in the fluorescence quenching of the IgG by crebanine, and some embedded hydrophobic patches of the IgG are exposed upon interaction with crebanine, while the characteristic β-sheet conformation of the IgG was almost preserved. Theoretical studies also show that several hydrophilic and hydrophobic residues play a crucial role in the formation of hydrogen bonds between crebanine and IgG, along with the stability of the complex. Cellular studies indicate that crebanine induces selective anticancer effects in MCF-7 cells (IC: 36.76 μM) compared to human embryonic kidney cells (HEK-293, IC: 723.77 μM) through the inhibition of colony formation, induction of oxidative stress and lipid peroxidation, upregulation of the Bax/Bcl-2 ratio, and cytochrome c release, which are indicative of the intrinsic apoptosis pathway. In conclusion, this study provides valuable information regarding the protein binding affinity and anticancer activity of crebanine, which are essential factors for determining the pharmacological activity of small molecules as drug candidates.