Chemopreventive catechin hydrate interaction with self-aggregated structures – A thermo-acoustic, spectroscopic and electrochemical study

Abstract

Tea catechins exhibit physiological effects including chemopreventive and chemotherapeutic activities. Despite having intestinal accessibility, their bioavailability is limited by their poor stability and permeability through the biological membranes. The interactions of a pharmacologically active molecule with biological membranes are crucial to manifest health-related effects. Nevertheless, improving the knowledge of biophysical interactions of “active” natural chemopreventives with cellular membranes can play a vital role in designing and developing new anti-cancer regimens. To deal with this issue, pseudo-membrane models comprising ionic and non-ionic micelles have provided a useful way to explore in vitro drug-membrane interactions at the molecular level. The present study focuses on physicochemical interactions of a potent flavonol, catechin hydrate (CH) with micelles of ionic (dodecyl trimethylammonium bromide, DTAB; and sodium dodecyl sulfate, SDS) and non-ionic (tween-80 and TX-100) surfactants at the molecular level in the aqueous medium. Various volumetric and acoustic parameters including apparent molar volume (ɸV), isentropic compressibility (Ks), apparent molar isentropic compressibility (ɸk), specific acoustic impedance (Z), relative association (RA), intermolecular free length (Lf) and the speed of sound (U) were calculated and interpreted in terms of solute/solvent–solute/solvent interactions using the cosphere overlap model and the electrostriction effect. Further, UV spectroscopy, conductivity, and electrochemical studies are used to predict the locus of CH in the micelles, binding constant (Kb), partition coefficient (Kc), and free energy changes of CH-micelle systems and redox behavior of the CH in the presence of surfactants.