The human colon carcinoma HT-29 cell line was selected as a model for human colon epithelial cells. Cells were maintained in a humidified atmosphere of 5% CO2 and 95% air at 37 C in supplemented McCoy’s 5a medium (with L-glutamine and sodium bicarbonate) containing 10% (v/v) FBS and 1% (v/v) each of streptomycin and penicillin. Three days after seeding, the cells were washed with PBS and incubated with cell culture medium supplemented with the studied diluted astaxanthin nanodispersions with selected food systems. The total concentration of astaxanthin in the food systems was set at 10 lM. Cell monolayers were rinsed with PBS and detached by trypsinisation after an additional 48 h of incubation with the supplemented culture medium under maintenance conditions (37 C and 95% air, 5% CO2) and were resuspended in 10 ml culture media. An aliquot of the suspension was used for the determination of cell number, and the remainder of the cell suspension was rinsed with PBS and suspended in 2 ml water/ethanol (1:1, v/v). The cellular astaxanthin was extracted three times with methanol/DCM (1:1, v/v) and quantified by HPLC (Anarjan et al., 2011).