Investigation on the interaction of aromatic organophosphate flame retardants with human serum albumin via computer simulations, multispectroscopic techniques and cytotoxicity assay.

Organophosphate flame retardants (OPFRs) are newly emerging estrogenic environmental pollutants, which attracted widespread public interest owing to their potential threats to human. Here, the interaction between two typical aromatic OPFRs, TPHP/EHDPP and HSA was researched by different experiments. Experimental results indicated that TPHP/EHDPP can insert the site I of HSA and be encircled by several amino acid residues, Asp451, Glu292, Lys195, Trp214 and Arg218 played vital roles in this binding process. At 298 K, the K value of TPHP-HSA complex was 5.098 × 10 M, and the K value of EHDPP-HSA was 1.912 × 10 M. Except H-bonds and van der Waals forces, the π-electrons on the phenyl ring of aromatic-based OPFRs played a pivotal role in maintaining the stability of the complexes. The content alterations of HSA were observed in the present of TPHP/EHDPP. The IC values of TPHP and EHDPP were 157.9 μM and 31.14 μM to GC-2spd cells, respectively. And the existence of HSA has a regulatory effect on the reproductive toxicity of TPHP/EHDPP. In addition, the results of present work implied Ka values of OPFRs and HSA are possible to be a useful parameter for evaluating their relative toxicity.