Investigation of in vitro antibacterial, antiglycation, and antioxidant activities of selamectin/chlorogenic acid system and their interaction with immunoglobulin G.

The interaction mechanism between chlorogenic acid (CGA) and/or selamectin (SEI) and immunoglobulin G (IgG) was studied by multispectral techniques and molecular docking, and the effect of the complex formation on the protein's functional properties was then evaluated. The results showed that CGA or SEI binds to the different site on IgG chain through different binding forces, which induces different influence on the protein's secondary structure. The interaction of IgG with CGA is higher than that of IgG with SEI due to the multiple hydroxyl groups, the flexible and compact structure of CGA. When two drugs coexist, the pre-added drug can all decrease the interaction intensity between the subsequently added drug and IgG. The results of the biological activity experiments showed that CGA exhibits excellent antioxidant and antidiabetic activities, while SEI displays excellent antibacterial and antidiabetic performance. These biological activities were affected in varying degrees by the drug combination and the related complex formation with IgG. In addition, the antiviral potential of CGA and SEI was preliminary predicted by molecular docking, and their strong binding to SARS-CoV-2 main protease (Mpro) may indicate the good antiviral activity of the drug combination. It is expected to provide theoretical support for developing more efficient antibacterial and antiviral drugs by the results of this research, and for rational drug co-administration in treating specific diseases.