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

Ramsia Geisler,Sylvain Prévost,Rajeev Dattani,Thomas Hellweg

doi:10.3390/cryst10050401

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.

Highlights

Aescin is a mixture of the triterpene saponins extracted from the seeds of the horse chestnut tree Aesculus hippocastanum [1,2,3,4,5,6,7]
Tm the acyl chains undergo a conformational transition from all trans to partially gauche configuration leading to the more disordered arrangement of lipid molecules and the flexible fluid Lα phase of DMPC is reached
We employed wide-angle X-ray scattering (WAXS) in order to discuss the effect of β-aescin on local structural parameters of a DMPC bilayer and on the cooperative phase transition of the lipid molecules on the sub-nm scale

Summary

Introduction

Aescin (or escin) is a mixture of the triterpene saponins extracted from the seeds of the horse chestnut tree Aesculus hippocastanum [1,2,3,4,5,6,7]. The active compound in this mixture is β-aescin, which is the key molecule in this work [8]. It has gained significant attention in the last 10 years especially in relation to aescins’ pharmacological activity [9,10,11,12,13,14]. Aescin has been investigated with respect to its potential for anti-cancer therapy [20,21,22]. Its growth-inhibiting activity against glioblastoma-initiating cells (GIC) is remarkable and is more efficient compared to clinically used drugs [23]. It was found to augment the effects of existing chemotherapeutic drugs [20]

Methods

Results

Conclusion