Influence of curcumin on membrane properties : curcumin as a molecular probe to study 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposomes while interacting with ionic liquids / by Elsy Daniel El Khoury.

Abstract

Extensive research is currently focused on curcumin as a potential novel drug for near future to control various diseases including inflammatory disorders, carcinogenesis, AlzheimerΓÇÖs disease and oxidative stress-induced pathogenesis. Therapeutic utility of curcumin is limited due its poor water solubility and its fast degradation. Therefore, methods are being developed through synthetic approach to alter its properties or incorporate it into different host systems to improve the curcumin delivery system. Earlier it was established from our research group that fluorescence characteristics of curcumin is susceptible to aggregation behavior. In this thesis we report that the fluorescence intensity of curcumin is sensitive to the viscosity and thus the fluidity of the solvent. The partition coefficient of curcumin with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-Dipalmitoyl-sn-Glycero-3-Phosphocholine (DPPC) liposomes were measured and found to be high. We concluded that curcumin binds strongly to liposomes and at high concentrations curcumin influences the phase transition temperature of liposomes but at low concentration it does not influence it appreciably. Thus we use curcumin at low concentration range to probe the properties of these two bilayers. Fluorescence intensity of curcumin ΓÇô temperature profile was successfully applied to determine the phase transition temperature of these liposomes. We used ethanol to induce interdigitation between the hydrophobic chains of the lipids and studied this effect using curcumin as fluorescence probe. Increased and wider use of ionic liquids (ILs) for various applications recently has drawn attention to its toxicological consequence on human health. To explore effect of ILs on membrane properties, we also monitored the interactions of ILs such as 1-methyl-3-octylimidazolium chloride (moic), 1-buytl-3-methyl imidazolium tetrafluoroborate (bmit) and 1-benzyl-3-methyl imidazolium tetrafluoroborate (bzmit) with DMPC and DPPC. We studied their effect