Stereochemistry of tropane alkaloid formation in Datura

Five-month-old Datura innoxia plants were fed via the roots with either d(+)-hygrine-2′-¹⁴C] or l(?)-hygrine-2′-¹⁴C]. After 7 days the root alkaloids 3α,6β-ditigloyloxytropane, 3α,6β-ditigloyloxytropan-7β-ol, hyoscine, hyoscyamine and cuscohygrine were isolated from both groups of plants. d(+) but not l(?)-hygrine acts as a precursor for the tropane alkaloids whereas both enantiomers appeared to serve equally well in the biosynthesis of cuscohygrine.