Antioxidant in a model biomembrane – astaxanthin and its esters mixed with DPPC in Langmuir films

Amphiphilic properties of astaxanthin molecule and its esters make it possible to include it in self-organized structures based on lipid membrane components. Astaxanthin and its mono- and diesters were isolated from the extract of the microalgae Haematococcus Pluvialis , purified by column chromatography, and identified by thin-layer chromatography. The absence of impurities in astaxanthin and its esters was confirmed by means of high performance liquid chromatography method with detection in the ultraviolet-visible region and mass spectrometric detection. The model systems of the cell membrane lipid bilayer — Langmuir films of mixtures of DPPC with astaxanthin and its mono- and diesters, were formed at the air-water interface and studied by a complex of methods. It was found that an increase in the amount of astaxanthin, as well as the addition of its esters to the Langmuir films of DPPC, leads to an increase of values of area per molecule at the surface pressure isotherm uprise and decrease of Langmuir film collapse pressure. The addition of astaxanthin mono- and diesters prevents the phase transition in the DPPC monolayer more strongly than unesterified astaxanthin.