Molecular properties of astaxanthin in water/ethanol solutions from computer simulations

Research output: Contribution to journalArticle

Abstract

Astaxanthin (AXT) is a reference model of xanthophyll carotenoids, which is used in medicine and food industry, and has potential applications in nanotechnology. Because of its importance, there is a great interest in understanding its molecular properties and aggregation mechanism in water and mixed solvents. In this paper, we report a novel model of AXT for molecular dynamics simulation. The model is used to estimate different properties of the molecule in pure solutions and in water/ethanol mixtures. The calculated diffusion coefficients of AXT in pure water and ethanol are (3.22 ± 0.01) × 10–6 cm2 s–1 and (2.7 ± 0.4) × 10–6 cm2 s–1, respectively. Our simulations also show that the content of water plays a clear effect on the morphology of the AXT aggregation in water/ethanol mixture. In up to 75% (v/v) water concentration, a loosely connected network of dimers and trimers and two-dimensional array structures are observed. At higher water concentrations, AXT molecules form more compact three-dimensional structures that are preferentially solvated by the ethanol molecules. The ethanol preferential binding and the formation of a well connected hydrogen bonding network on these AXT clusters, suggest that such preferential solvation can play an important role in controlling the aggregate structure.

Details

Authors
  • Khadga Jung Karki
  • Susruta Samanta
  • Danilo Roccatano
External organisations
  • Jacobs University
  • University of Cagliari
  • University of Lincoln
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
Original languageEnglish
Pages (from-to)9322-9328
JournalThe Journal of Physical Chemistry Part B
Volume120
Issue number35
Publication statusPublished - 2016 Sep 8
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes