Binding and toxicological insights into Direct Yellow 8 and bovine serum albumin: fluorescence quenching and cytotoxicity studies

Abstract Industrial dyes are ubiquitous in nature, making it essential to assess their toxicological effects on humans and animals. Azo dyes, due to their structural composition (azo linkages), are resistant to biodegradation. Direct Yellow 8 (DY8), a monoazo industrial dye, may exhibit carcinogenic properties; therefore, it is imperative to extensively explore its effects on biomolecules. In this study, for the first time to the best of our knowledge, we elucidate the binding interaction between DY8 and bovine serum albumin (BSA) using multi spectroscopic techniques. Changes in the secondary structure of BSA were assessed using circular dichroism (CD). Fluorescence (FL) intensity of BSA was quenched upon interacting with DY8. Moreover, the lifetime of BSA is nearly constant in the presence of DY8. The change in the absorption spectrum, along with the constant FL lifetime in the presence of DY8, ensures the dominant static quenching. Molecular docking and dynamics simulations revealed a stable binding configuration with minimal fluctuation. Furthermore, the effect of DY8 in human embryonic kidney 293 (HEK 293) cells has also been discussed.