Metabolism and biological potency of 5 6,-monoepoxy-β-carotene and 5,6:5′,6′-diepoxy-β-carotene

Abstract

5,6-Monoepoxy-[beta]-carotene and 5,6:5[image],6[image]-diepoxy-[beta]-carotene were partially converted into the furanoid forms during passage through the rat stomach. The monoepoxide was converted into vitamin A in the small intestine and showed a biological potency 21% of that of [beta]-carotene. Neither [beta]-carotene nor 5,6-monoepoxyvitamin A was formed. Intraperitoneal administration of the monoepoxide led to the accumulation of the unchanged compound in the liver and other tissues. The diepoxide gave no [beta]-carotene or vitamin A or 5,6-monoepoxyvitamin A when given orally and showed no biological potency. The significance of these results with special reference to the mechanism of formation of vitamin A from [beta]-carotene is discussed.