Protective effect of flavonoids and tocopherol in high altitude hypoxia in the rat: comparison with ascorbic acid.

The mixture of flavonoids (silymarin) from Carduus Marianus (0.9 mg.g-1 body weight) and/or ascorbic acid (0.4 mg.g-1 body weight) were administered in the food to 21 day-old (b.w. 35-45 g) rats for one week. Then the animals were exposed, in a hypobaric chamber, to simulated altitude 8,000-12,000 m for one hour. Mean lethal altitude was calculated by the Behrens equation: it was 10,150 m in controls, 10,550 m in ascorbic acid treated, 10,500 m in silymarin and tocopherol treated and 10,450 m in animals, receiving both ascorbic acid and silymarin. Thus silymarin protected the animals against lethality of high-altitude hypoxia. The effect of ascorbic acid and silymarin were not additive.