Supercritical carbon dioxide anti-solvent precipitation of anti-oxidative zeaxanthin highly recovered by elution chromatography from Nannochloropsis oculata

Zeaxanthin, a kind of xanthophylls, rich in Marigold flowers and a few micro algae, acts as a strong antioxidant capable of protecting human eye-sight from age-related macular degeneration. This study examined elution chromatography coupled with supercritical anti-solvent precipitation applied for generation of zeaxanthin-rich particulates from micro-algal Nannochloropsis oculata species. Crude of the ultrasonic acetone extract subjected to the column fractionation successfully yields a fraction containing 303.02 mg/g (30%) of zeaxanthin with recovery of 90%. Supercritical anti-solvent precipitation of the algal solution at 200 bar and 313 K was used in producing submicron-sized particulates of 50% zeaxanthin. These extracts were subjected to tests of antioxidant capacities in 2,2-diphenyl-2-picrylhydrazyl hydrate free-radical assay and human adult retinal pigment epithelium-19 cells. This work provided a fast and environmental benign process to generate anti-oxidative capable algal micronized powders from the N. oculata.

► Ultrasonic acetone extraction of sight-protecting zeaxanthin from microalgae is fast with high recovery.
► Reverse phase column chromatography increased concentration of zeaxanthin in elution.
► Supercritical anti-solvent precipitation successfully generated sub-micron sized zeaxanthin within minutes.
► Anti-oxidative capacity of DPPH free radicals and ARPE-19 cells by zeaxanthin was evidenced in vitro.