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International audience; Cucurbitacin E (Cuc E), highly oxygenated triterpene from cucurbitaceae ă family, was demonstrated to possess anti-proliferative, ă anti-inflammatory and anti-oxidant activities. Here, we studied the ă effect of Cuc E on the properties of the phospholipid membrane. Large ă unilamellar vesicles, with and without sulforhodamine B (SRB), were ă prepared in the absence and presence of Cuc E. The fluorescence ă increase, resulting from SRB release from vesicles due to inhibition of ă auto-quenching, was used to assess the permeability of liposome at 4 ă degrees and 37 degrees C. At 4 degrees C, blank liposomes and those ă containing Cuc E were stable; while at 37 degrees C Cuc E loaded ă liposomes showed less stability than blank ones. The loading efficiency ă of Cuc E into the vesicles was demonstrated to be 85% by HPLC. Dynamic ă light scattering measurements showed that liposomes embedding Cuc E were ă smaller than those which did not. Multilamellar vesicles were ă manufactured from dipalmitoylphosphatidylcholine in the presence and ă absence of Cuc E (molar ratio 7%). Results obtained by differential ă scanning calorimetry suggest that Cuc E binds mainly at the polar/apolar ă interfacial region of lipid bilayers and may incorporate into the lipid ă bilayer. Cuc E does not produce phase separation and thus might be ă included in liposome formulation. (C) 2013 Elsevier B.V. All rights ă reserved.

Cucurbitacin E (Cuc E), an oxygenated triterpene molecule, has demonstrated anti-proliferative effect on various cancer cells. Here, we examined the effect of Cuc E on the membrane morphology and properties using differential scanning calorimetry, transmission electron microscopy and atomic force microscopy techniques. Dipalmitoylphosphatidylcholine vesicles were prepared by the thin film hydration method in the absence and presence of Cuc E at molar ratios 100:12 and 100:20. The loading efficiency of Cuc E was found to be higher than 98% upon HPLC analysis. The thermodynamic parameters suggest that Cuc E does not penetrate into the bilayers and interacts with the polar/apolar interface of the lipid membranes. Blank and Cuc E loaded liposomes prepared from a mixture of DPPC/DPPE/DPPG/Cho were imaged by TEM and AFM. Images obtained by TEM revealed unilamellar liposomes for blank and Cuc E loaded liposomes. AFM images showed that the size and the height of Cuc E loaded liposomes were respectively smaller and higher than blank ones. Results suggest that Cuc E produces modifications in the lipid membrane structures.