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

Karki, Khadga Jung and Samanta, Susruta and Roccatano, Danilo (2016) Molecular properties of astaxanthin in water/ethanol solutions from computer simulations. The Journal of Physical Chemistry B, 120 (35). pp. 9322-9328. ISSN 1520-6106

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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} cm^{2}s^{-1} and (2.7+/-0.4) 10^{-6} cm^{2}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, 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.

Keywords:Natural Compounds, Molecular dynamics simulations, Self-diffusion coefficient, Drug aggregation, Carotenoids, NotOAChecked
Subjects:C Biological Sciences > C760 Biomolecular Science
F Physical Sciences > F170 Physical Chemistry
F Physical Sciences > F100 Chemistry
Divisions:College of Science > School of Mathematics and Physics
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ID Code:23775
Deposited On:21 Aug 2016 11:00

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