Protective effect of Dunaliella bardawil on water-immersion-induced stress in rats

The functional activity of a natural isomer mixture as compared with synthetic all-trans beta-carotene in rats was investigated in a rat model produced by water-immersion restraint stress. Five-week-old male rats were fed diets supplemented with synthetic all-trans beta-carotene, dry Dunaliella bardawil, and purified natural beta-carotene from D. bardawil at equivalent levels of beta-carotene. After the rats were fed diets containing up to 0.1% beta-carotene for 2 weeks, they were restrained in a wire cage and immersed in a 23 degree C water bath for 20 h. Liver analyses indicated that rats showed higher accumulations of the algal beta-carotene isomer mixture than of the synthetic all-trans beta-carotene. Dunaliella bardawil and purified natural beta-carotene significantly decreased the gastric mucosal lesions. Synthetic beta-carotene did not decrease the lesions. These results suggest that the gastric cytoprotective effect of beta-carotene depends on the amount of beta-carotene accumulated in the body.