With a protection factor of 22.6 +- 1.7 units, was better than that of alpha-tocopherol (8.5+-1.5 units). The higher antioxidant activity of the astaxanthin-rich fration was also indicated by a higher protection factor (14.1 +- 3.2 units) compared to alpha-tocopherol (6.2+-0.1 units) against singlet oxgen mediated oxidation of liposomes.