Genotoxicity and subacute toxicity studies of a new astaxanthin-containing Phaffia rhodozyma extract

Experimental and clinical studies demonstrate that astaxanthin (AXN), a xanthophyll carotenoid, has protective effects against oxidative damage. Because most of these studies assessed AXN derived from Haematococcus pluvialis that were cultivated at industrial scales, few studies have examined the toxicity of AXN derived from Phaffia rhodozyma. To evaluate the safety of astaxanthin-containing P. rhodozymaextract (AXN-PRE), genotoxicity was assessed in bacterial reverse mutation test and mouse bone marrow micronucleus test, and general toxicity was assessed in 4-week repeated oral toxicity study in rats. AXN-PRE did not induce reverse mutations in the Salmonella typhimurium strains TA98 or TA100 at concentrations of 5,000 µg/plate with or without S9 mix, and no chromosome damage was observed at a dose of 2,000 mg/kg in mouse micronucleus test. In the subacute toxicity study, male and female Sprague-Dawley rats were given AXN-PRE at doses of 0, 500, and 1,000 mg/kg by gavage for 4 weeks. Body weights, urinalysis, hematology, serum biochemistry, organ weights, or histopathological lesions indicated no distinct toxicity. In conclusion, AXN-PRE had no effect in bacterial reverse mutation test and mouse bone marrow micronucleus test. The no-observed-adverse-effect level for AXN-PRE in 4-week repeated oral toxicity study in rats was determined to be greater than 1,000 mg/kg (corresponding to dose of 50 mg/kg AXN) regardless of gender.