Interaction of curcumin with diarachidonyl phosphatidyl choline (DAPC) liposomes: Chitosan protects DAPC liposomes without changing phase transition temperature but impacting membrane permeability.

The developing public interest in traditional medicine, especially plants-based drug, has prompted extensive research on the potential of naturally existing compounds. Among these compounds, curcumin is currently one of the most studied substances. In this study, we elaborate the physical properties of diarachidonyl phosphatidyl choline (DAPC) liposome using fluorescence method, where curcumin at low concentration was used as a probe molecule. In the first place, the phase transition temperature of DAPC was determined by following the fluorescence intensity of curcumin as a function of temperature, along with evaluating the effect of concentration of curcumin in the presence or absence of chitosan oligosaccharide lactate as an additional protective layer. On the other hand, quenching reactions using CPB and KI as quenchers reflected the ease of entry of different concentrations of these quenchers to the curcumin located in the hydrophobic core of the liposome which give new insight about the lipophilicity and permeability of the DAPC membrane. Finally, the partition coefficient analysis was investigated. It was concluded that curcumin has a higher partition coefficient at a temperature above the phase transition temperature of DAPC liposomes where the liposome is in the fluid liquid crystalline phase. Modulation of liposomes properties in the presence of chitosan oligosaccharide lactate layer was for the first time investigated. Chitosan oligosaccharide lactate acts as protecting layer without changing the phase transition temperature, but it affects the membrane permeability depending on solid gel and liquid crystalline phase.