Biosynthesis of piperidine alkaloids

History, chemistry and biology of alkaloids from Lobelia inflata

“…Among this family, Lobelia inflata contains the greatest concentration of more than 20 piperidine alkaloids 6 (see Figure 1 for the identification of [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. (K)-Lobeline 1 is the major and the most biologically active alkaloid of the plant.…”

Tropane and Granatane Alkaloid Biosynthesis: A Systematic Analysis

“…Radioactive acetate is incorporated into GAs regardless of which species is fed [116][117][118][119]. As is In all three hypotheses the origin of the N-methyl group is via labeled methionine [121].…”

“…The general consensus is that lysine (25) is the starting substrate for the entry into granatane biosynthesis. In several cases, different forms of labeled lysine were found incorporated into the core granatane structure [115][116][117][118][119][120]. Sedum sarmentosum 6-14 C-DL-lysine N-methylpelletierine asymmetrically [117] Sedum sarmentosum 4,5-3 H 2 ,6-14 C-DL-lysine N-methylpelletierine [117] Over the course of studies regarding granatane and piperideine alkaloid biosynthesis, there has been some controversy over the origin of the intermediates in the biosynthetic pathway.…”

“…Hypothesis I is based on the observation that P. granatum plants fed [1.5-14 C] and [1.5-14 C 3 H 2 ] cadaverine yields incorporation of the labels into N-methylpelletierine (7) and pseudopelletierine (6) [121]. In this pathway, lysine (25) is first decarboxylated to form cadaverine (26) which would subsequently be methylated to form N-methylcadaverine (27) [119]. N-methylcadaverine (27) would then be oxidized to form 5-methylaminopentanal (28) promoting a spontaneous cyclization to form the N-methyl-∆ 1 -piperidinium cation (29).…”

“…Radioactive acetate is incorporated into GAs regardless of which species is fed [116][117][118][119]. As is the case with tropane alkaloid biosynthesis, the enzymes involved in the extension and cyclization reactions of granatanes includes a putative polyketide synthase.…”