Biosynthesis of securinine,the main alkaloid of Securinega suffruticosa

Biosynthesis of securinine was studied by incorporation experiments in Securinega suffruticosa. Among presumed precursors tested, lysine, cadaverine, and tyrosine showed the highest incorporation into securinine. Degradation experiments revealed that cadaverine-1,5-¹⁴C] labelled specifically the piperidine ring of securinine and the radioactivity from dl-tyrosine-2-¹⁴C] was introduced into the C-11 lactone carbonyl. Experiments with L-tyrosine-U-¹⁴C] and L-tyrosine-3′,5′-³H; U-¹⁴C] prove that the remaining C₆Sz.sbnd;C₂ moiety is derived from the aromatic ring and the C-2 and C-3 or tyrosine.