Molecular organization of 2-(2,4-dihydroxylphenyl)-5,6-dichlor 1,3-benzothiazole in monomolecular layers formed with diphytanoylphosphatidylcholine: A linear dichroism–FTIR study

2-(2,4-Dihydroxylphenyl)-5,6-dichlor 1,3-benzothiazole (dHBBT) has very strong antifungal and antitumoral properties in relation to human cancer cells. The aim of this research was to analyze the binding process of dHBBT molecules to the lipid membrane formed from DPhPC at the air–water interface. The effect of dHBBT on the organization of lipid membranes formed with diphytanoylphosphatidylcholine (DPhPC) was studied with the application of monomolecular layer technique, FTIR spectroscopy and linear dichroism–FTIR. On the basis of linear dichroism experiments the mean orientation angle θ between the molecular axis and the normal to monolayer surface was determined. Mean value was calculated at θ = 72° and indicates a horizontal orientation of dHBBT molecules in the lipid membrane formed from DPhPC. dHBBT molecules have considerable influence on the orientation of DPhPC acyl chains. The mean value of the angle between normal to monolayer surface and the main axis of the acyl chain is approximately 45° for DPhPC, while for the lipid monolayer containing dHBBT it is approximately 18°. Such extreme changes in orientation of acyl chains indicate a clear influence of the relationship on the dynamic and structural properties of the monolayer formed from DPhPC. Biological activity of dHBBT molecules is tightly associated with its molecular organization. The results of the research presented in this work are potentially valuable in respect of the development of pharmacologically active preparations of dHBBT.