2006 Volume 17 Issue 1 Pages 34-39
Reductive metabolic conversion to retinol of Carophyll-red and Carophyll-pink (water soluble beadlet of non-provitamin A carotenoids, Canthaxanthin and Astaxantin) feeding in vitamin A deficient rats was investigated.
Male Std Wistar rats, 3-weeks old, were fed a vitamin A deficient diet for 35days prior to the experiment. Carophyll-red or Caropphll-pink was given for 8 days, and the change in the body weight of each group was measured. The serum and liver levels of retinol, retinyl ester, and the retinol binding protein (RBP) were determined.
The reduced body weight of the rats fed the vitamin A-deficient diet significantly increased by the administration of Carophyll-red and Carophyll-pink. The change in the body weight ratio compared to the control group was 1.9 times higher in the Carophyll-red group and 1.3 times higher in the Carophyll-pink group. The serum retinol levels of the Carophyll-red group and Carophyll-pink group were 2.0 and 1.2 times higher than that of the control group. The serum RBP levels of the Carophyll-red group and Carophyll-pink group were 1.6 and 1.3 times higher than that of the control group.
These results may suggest that both Canthaxanthin in Carophyll-red and Astaxanthin in Carophyll-pink were converted into retinol by the oxidative reaction of each carotenoid due to reductive reagents, such as sugars, in the water soluble beadlet, because the conversions from Canthaxanthin and Astaxanthin to retinol are difficult in mammals unless some reductive reagents are included in the diets. Other anti-oxidative reagents in the beadlet and/or diet, such as Ethoxyquin, may also play a synergistic-reductive action. Further study is needed to confirm this hypothesis.
