Effect of Cholesterol and Ibuprofen on DMPC-β-Aescin Bicelles: A Temperature-Dependent Wide-Angle X-ray Scattering Study

Abstract

β -aescin is a versatile biosurfactant extracted from the seeds of the horse chestnut tree Aesculus hippocastanum with anti-cancer potential and is commonly used in the food and pharmaceutical and cosmetic industries. In this article, wide-angle X-ray scattering (WAXS) is used in order to study the modifications of the structural parameters at the molecular scale of lipid bilayers in the form of bicelles composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the triterpenoid saponin β -aescin. In particular, the impact on the cooperative phase transition and the structural parameters of the DMPC bilayers at different compositions and temperatures is of special interest. Moreover, we show how cholesterol and the non-steroidal anti-inflammatory drug (NSAID) ibuprofen modulate the structural parameters of the β -aescin-DMPC assemblies on a molecular scale. Ibuprofen and cholesterol interact with different parts of the bilayer, namely the head-region in the former and the tail-region in the latter case allowing for specific molecular packing and phase formation in the binary and ternary mixtures.

Stable DOPG/Glycyrrhizin Vesicles with a Wide Range of Mixing Ratios: Structure and Stability as Seen by Scattering Experiments and Cryo-TEM

“…It is expected that incorporated glycyrrhizin will, at least at higher contents, significantly contribute to the WAXS signal. Similar observations were made for the incorporation of aescin into DMPC bilayers [ 66 , 67 ].…”

“…It is expected that incorporated glycyrrhizin will, at least at higher contents, significantly contribute to the WAXS signal. Similar observations were made for the incorporation of aescin into DMPC bilayers [66,67]. Several simulation studies in literature suggest that glycyrrhizin is fully incorporated into the hydrophobic part of the membrane in case of the lipids DPPC or DOPC [26,29,69].…”

Interactions between DMPC Model Membranes, the Drug Naproxen, and the Saponin β-Aescin

“…The head group consists of one or more sugar moieties [ 26 , 27 , 28 , 29 ]. Saponins also interact with phospholipid membranes, red blood cells, and cancer cells, as they are able to alter the membrane properties and structure [ 30 , 31 , 32 , 33 , 34 , 35 ]. The well-known saponin -aescin is studied here [ 36 , 37 ].…”

Expanding the Toolbox for Bicelle-Forming Surfactant–Lipid Mixtures

“…These structures spontaneously assemble by mixing phospholipids and a detergent at a given lipid:detergent molar ratio (q), which determines the particle size, and their properties vary depending on experimental conditions, such as lipid and detergent type and concentration, buffer ionic strength, and temperature [ 1 , 2 , 3 ]. Their high compositional tunability, along with stability against several freeze–thawing cycles, makes bicelles popular as models of cellular membranes for the study of both transmembrane protein structure and functioning and their intermolecular interactions in a native-like environment [ 4 , 5 ].…”