Nature of the Vitamin A Activity of Annatto Seed (Bixa orellana L.)

The high vitamin A activity of the petroleum ether extract of the annatto seed has been confirmed. It ranges from 1,000 to 2,000 international units of vitamin A per gram of extract. It was found that a standard mixture of 3-percent acetone in petroleum ether did not remove any vitamin A-active material from a magnesium oxide-hyflo supercel column, on which a petroleum ether extract of annatto had been chromatographed. The only solvent among those tried, that effectively removed the material which was left absorbed on the column after elution with acetone-petroleum ether was methanol. The methanol extract exhibited a biological activity of about the same order of magnitude as the original petroleum ether extract, that is, 1,000 to 2,000 international units of vitamin A.