Atropine Dynamics in Seedlings of Duboisia myoporoides

Summary Changes in atropine distribution, degradation and metabolite production during culture were determined when [carbonyl- 14 C]atropine sulfate was supplied as a tracer to 2- to 3-month-old seedlings of Duboisia myoporoides through the root which is the site of biosynthesis, and then cultured for 1 to 11 weeks. All radioactivity was recovered in 80 % MeOH extracts from A) non-powdered tissues and then B) powdered tissues, but negligible activity in the tissue residue: Extracts A and B seemed to contain radioactivity mainly from the vascular tissues and from the fundamental tissues of the plant, respectively. The radioactivity in the fundamental tissues increased with the decrease in the vascular system during culture. Leaves detached before end of culture showed little activity in the vein. Atropine was degradated exponentially and the half-life of atropine in seedlings was near 3 weeks. According to the decrease of atropine, metabolites appeared; not only alkaloidal products scopolamine and aposcopolamine, but also non-alkaloidal metabolites, one of which corresponded to tropic acid. Other metabolites were determined by alkali hydrolysis as esterified products between tropic acid and unknown substances. Atropine dynamics in the seedlings of D. myoporoides was discussed.