A comparison of the anticancer activities of dietary beta-carotene, canthaxanthin and astaxanthin in mice in vivo

The anticancer activities of beta-carotene, astaxanthin and canthaxanthin a gainst the growth of mammary tumors were studied in female eight-wk-old BAL B/c mice. The mice power were fed a synthetic diet containing 0, 0.1 or 0.4 % beta-carotene, astaxanthin or canthaxanthin. After 3 weeks, all mice were inoculated with I x 10(6) WAZ-2T tumor cells into the mammary fat pad All animals were killed on 45 d after inoculation with the tumor cells. No caro tenoids were detectable in the plasma or tumor tissues of unsupplemented mi ce. Concentrations of plasma astaxanthin (20 to 28 mu mol/L) were greater ( P < 0.05) than that of beta-carotene (0.1 to 0.2 mu mol/L) and canthaxanthi n (3 to 6 mmol/L). However, in tumor tissues, the concentration of canthaxa nthin (4.9 to 6.0 nmol/g) was higher than that of beta-carotene (0.2 to 0.5 nmol/g) and astaxanthin (1.2 to 2.7 nmol/g). In general, all three caroten oids decreased mammary tumor volume. Mammary tumor growth inhibition by ast axanthin was dose-dependent and was higher than that of canthaxanthin and b eta-carotene. Mice fed 0.4% beta-carotene or canthaxanthin did not show fur ther increases in tumor growth inhibition compared to those fed 0.1% of eac h carotenoid. Lipid peroxidation activity in tumors was lower (P < 0.05) in mice fed 0.4% astaxanthin, but not in those fed beta-carotene and canthaxa nthin. Therefore, beta-carotene, canthaxanthin and especially astaxanthin i nhibit the growth of mammary tumors in mice; their anti-tumor activity is a lso influenced by the supplemental dose.