Table of Contents
Journal of Thermodynamics
Volume 2011, Article ID 137531, 7 pages
Research Article

Investigation on the Competition Interaction of Synthetic Food Colorants and Ciprofloxacin Hydrochloride with Bovine Serum Albumin by Fluorescence Spectroscopy

Key Laboratory of Medical Chemistry and Molecular Diagnosis, Ministry of Education, College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China

Received 12 June 2011; Accepted 3 September 2011

Academic Editor: Ali-Akbar Saboury

Copyright © 2011 Baosheng Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The effects of synthetic food colorants like tartrazine (TTZ), sunset yellow (SY), and erythrosine (ETS) on the binding reaction between ciprofloxacin hydrochloride (CPFX) and bovine serum albumin (BSA) were investigated by fluorescence spectroscopy in the aqueous solution of pH = 7.40. Results showed that CPFX caused the fluorescence quenching of BSA through a static quenching procedure and the primary binding site was located at subdomain IIA of BSA (site I). According to the calculated thermodynamic parameters, it confirmed that CPFX bound to BSA by electrostatic interaction. In addition, the colorants affected the formation of BSA-CPFX complex. This resulted in an increase of the free, biological active fraction of CPFX. The binding distance of BSA-CPFX systems was evaluated according to Förster's theory. Results suggested that the binding distance were increased in the presence of synthetic food colorants.