
Full text loading...
Purpose. To investigate the efficiency of natural astaxanthin that has been extracted from Xanthophyllomyces dendrorhous in inhibiting the proliferation and viability of colorectal adenocarcinoma cell line (Caco-2; colon cancer cells).
Methodology. Caco-2 cells and normal human oralkeratinocytes (NOKs) were treated with different concentrations of extracted astaxanthin, ranging from 0.075 to 10 mg ml−1, for 24, 48 and 72 h. The number of cells was determined via MTS assay and the proliferating cells were investigated by bromodeoxyuridine (BrdU) assay.
Results/Key findings. Of the Caco-2 cells, 30–50 % remained viable, while the NOKs showed 110–120 % survival when treated with 5 mg ml−1 astaxanthin. The Caco-2 cells showed distinct structural shrinkage when treated with the same concentration of astaxanthin. Fluorescent labelling of the DNA of the proliferative cells with BrdU showed a significant decrease in the number of the proliferative Caco-2 cells when the concentration of astaxanthin was increased to 5 mg ml−1.
Conclusion. The natural astaxanthin from X. dendrorhous, at an appropriate concentration, is effective in terminating the viability of, or retarding the proliferative activity of, Caco-2 cells, without harmful effects on NOKs.