Quinizarin interaction with bile salts micelles as biomimetic model membranes

Abstract

The evaluation of the interaction of quinizarin (Q), an analogue of the core unit of various anticancer drugs, with two bile salts sodium cholate (NaC) and sodium deoxycholate (NaDC) in 0.1 M phosphate buffer (pH 7.4), investigated by absorption and conductance measurements is presented in this work. The values of binding constant (Kb), partition coefficient (Kx) and free energy change (ΔG) were determined and discussed in terms of possible intermolecular interactions. The results indicate higher binding constant and partition coefficient values for NaDC micelles than NaC micelles and this distinct interaction of quinizarin with NaTDC and NaTC micelles is supported by the differences in nature and structure of bile salts micelles. The critical micelle concentration (CMC) of both bile salts, determined using electrical conductivity measurements is higher in the presence of quinizarin.