The biosynthesis of the Lythraceae alkaloids. I. The lysine-derived fragment

The biosynthesis of decodine (7) and decinine (9), Lythraceae alkaloids containing a trans-fused quinolizidine nucleus, was studied in intact plants of Decodonverticillatus (L.) Ell. Nonrandom incorporation of radioactivity from 14C-labelled samples of lysine, cadaverine, and Δ1-piperideine was demonstrated by partial degradation. Pelletierine did not serve as a precursor of the alkaloids. It was also shown, by means of 3H,14C-labelled tracers, that the alkaloids are derived from L-lysine whereas pipecolic acid, which is present in the plant, is derived from D-lysine.