[Per(6-deoxy) derivative of beta-cyclodextrin (B6): physicochemical characterization, haemolytic activity and membrane properties].

Natural beta-cyclodextrin bears an internal crown consisting of six primary alcohol groups. Their removal leads to per(6-deoxy)beta-cyclodextrin (B6). The physicochemical properties of B6 and its interactions with membranes were investigated to give an evaluation of haemolytic activity and complexing properties of this chemical species. This was achieved by using surface tension and haemolytic activity (i.e.DH50 determination, the concentration inducing 50% haemolysis) measurements,1H-31P-NMR and EPR spectroscopies. Whereas B6 solubility in the water is close to that of natural beta CD (about 5 g/L at 20 degrees C) and exhibits amphiphilic properties greater than those of beta CD (log P: -1.36 at 300 K), B6 forms micelles in aqueous solution of 20 molecules, even at low concentration 0.8mM. In addition, B6 exhibits tensioactive properties leading to solubilization and even, in some cases orientation of synthetic membranes. Although no complex formation with membrane components was observed, NMR and ESR showed interactions with the surface of the membrane. Subsequently, B6 exhibits an important haemolytic activity, whose mechanism, different from that of beta CD, is discussed.