THE BIOSYNTHESIS OF HYDRASTINE AND BERBERINE

The biosynthesis of hydrastine and of berberine was investigated by administering radioactive glucose, phenylalanine, tyrosine, and dopamine to Hydrastis canadensis L. Both hydrastine and berberine were found to be specifically derived from two molecules of tyrosine. The ratio of incorporation of the two molecules of radiotyrosine into hydrastine was not unity, and varied with time. Dopamine was also incorporated into hydrastine without randomization, but only one molecule was utilized. These results, which are consistent with the classical hypothesis and disprove the prephenic acid hypothesis of biogenesis, provide direct evidence for some of the steps in the biosynthetic pathway by which hydrastine and berberine are formed in the plant.