The Influence of 6-Shogaol, a Therapeutic Agent of Zingiber Officinale, on the Interaction of Ciprofloxacin with Bovine Serum Albumin

The binding of ciprofloxacin (CIP) to bovine serum albumin (BSA) in the presence and absence of 6-shogaol was investigated by multiple techniques. Fluorescence spectroscopy results indicated that CIP was able to quench BSA in the presence and absence of 6-shogaol through a static mechanism. The CIP and 6-shogaol binding to BSA leads to the increase of the binding constant (Ka) value of CIP to BSA. In accordance to the negative values of ΔH° and ΔS°, the functions of hydrogen bonding and van der Waals forces are very important in this special binding. In addition, the negative values of ΔH° and ΔS° for BSA-CIP in the presence of 6-shogaol have been larger than those of the absence of 6-shogaol, highlighting the role of hydrogen bonding and van der Waals forces. As indicated by the synchronized fluorescence spectroscopy at Δλ = 60 nm, the location of CIP with mixed BSA in binary and trinary systems has been nearer to Tyr residues.