Alkaloids Derived from Lysine

The amino acid L-lysine happens to be the homologue of L-ornithine, and it also caters as an alkaloid precursor, employing pathways that are analogous to those known for ornithine. The „additional methylene moiety? present in lysine affords the formation of six-membered piperidine ring systems, very similar to ornithine that provided five-membered ring systems, as shown below:
Piperidine Alkaloids
The various important alkaloids that essentially have the piperidine nucleus are, namely: Coniine, Lobeline, Lobelanine and Piperine, which shall be discussed individually in the sections that follows:
Lobelia inflata (Indian Tobacco) AND Lobeline
Lobelia inflata (Campanulaceae) grows wild in the U.S.A., the eastern and central part of Canada. The leaf has been used by Native Americans as an emetic since ancient times. From this plant, a large number of piperidine and N-methylpiperidine derivatives were obtained, and the main alkaloids are lobeline, lobelanine, and lobelanidine
Biosynthetically, these alkaloids may be formed by a double Mannich reaction between two molecules of phenylalanine (via cinnamic acid and benzoylacetate-coenzyme A) and one ?1-piperidium cation arizing from lysine .