Alkaloids and metabolism in a Duboisia hybrid

A Duboisia hybrid contained scopolamine, 6-hydroxyhyoscyamine and hyoscyamine as major alkaloids and similar minor alkaloids as the parent species, D. leichhardtii and D. myoporoides. Unlike D. myoporoides, there was almost complete absence of pyridine bases. Tritiated scopolamine was infiltrated into a 2-year-old, field grown tree via a wick method. The scopolamine administered was metabolised to aposcopolamine. Hyoscyamine, 6-hydroxy-hyoscyamine and other minor Duboisia alkaloids had specific activities that were too small for them to be direct metabolites of scopolamine. Activity was located in acidic fractions that were shown to contain aromatic protons and water soluble basic fractions and are presumed to be responsible for the activity of these other alkaloids. The metabolic process occurred within the bark; alkaloids already accumulated appeared to be removed from the metabolic process