Characterizing the Interaction of Carmine with Human Serum Albumin Using Biophysical and Molecular Docking Approaches

Abstract

Carmine (CRM) is regarded as a safe coloring agent derived from the cochineal insect and is used to impart red color in a variety of products ranging from food, beverages, and cosmetics to pharmaceutical drugs. However, various toxicological implications are associated with the use of CRM, viz. anaphylaxis, utricaria, rhinitis, asthma and other cytotoxic and genotoxic ramifications. Therefore, it is imperative to evaluate the toxicity of CRM at the molecular level. A number of biophysical and biochemical methods have been used to examine the impact of CRM on human serum albumin (HSA). The formation of a CRM–HSA complex was revealed by intrinsic fluorescence analysis. The resulting circular dichroism spectra showed that CRM binding reduces the amount of alpha helices present in HSA. The synchronous fluorescence spectroscopy revealed significant microenvironment changes around the tyrosine (Tyr) and tryptophan (Trp) residues in HSA upon CRM binding. The binding of CRM takes place at or close to site I of HSA while also having transient interactions at the subdomain IIA–IIB interfaces determined by the drug displacement and molecular docking studies. Our present research described in the paper, we believe, is significant to understand the CRM-induced toxicity in people.