Lysine Lobelia inflata

Alkaloids with the piperidine nucleus, such as pelletierine (Punica grana-tum), lobelanine Lobelia inflata) and piperine Piper nigrum), have a typical biosynthesis pathway. It starts with L-lysine and continues via cadaverine (biogenic amine), A -piperideine and A -piperidinium cations and lobelanine, to be synthesized as lobeline. Piperine is synthesized from A -piperideine via piperidine (Figure 49). For the transformation from A -piperideine to A -piperideine cation, the residue from acetyl-CoA is needed, together with SAM activity in the transformation to lobelanine. Piperine is synthesized from piperidine through the formation of amide. 

Lobeline.—The results of feeding experiments with DL-[2- C]lysine and dl-[2- Clphenylalanine in Lobelia inflata have shown that these amino-acids are both specific precursors for the alkaloid lobeline (13). In further experiments, DL-[3- C]phenylalanine, [3- C]cinnamic acid, and [3- C]-3-hydroxy-3-phenylpropionic acid [as (9)] have been found to be specific precursors for lobeline (13). These results are consistent with the anticipated pathway " to lobeline illustrated in Scheme 2, with benzoylacetic acid (10) as the intermediate which couples with A -piperideine to give the intermediate (11). The probability of 3-hydroxy-3-phenylpropionic acid (9) being an intermediate in lobeline biosynthesis is increased by the isolation of this acid from L. inflata ... 

Another series of lysine derived alkaloids occurs in the genus Lobelia (Campanulaceae). One of these compounds, lobeline (39) (Fig. 29.13) (from Lobelia inflata, Indian tobacco), has been used in antismoking preparations. Both lobeline and nicotine are classed as ganglionic stimulants. Therapeutically, lobeline is hardly used today (Fodor and Colosanti, 1985). Poisoning of cattle because of ingestion of Lobelia berlandieri has occurred in Texas and Mexico... 

Lobeline is found in Lobelia inflata along with lobelanine and lobelanidine. The main ring in lobeline is derived from lysine via piperidine, while the two benzene rings it contains derive from phenylalanine via the shikimic acid pathway (Samuelsson 1992). 

The biosynthesis, occurrence, and biological activities of piperidine alkaloids arising from lysine have been studied Punica granatum. Piper species, and Lobelia inflata). The isolation process, chromatographic purification/analysis, and structure elucidation of the significant alkaloids are discussed. 

While for developing of simple piperidine alkaloids, e.g., pelletierine (Punica granatum), piperine (Piper nigrum et longum), and lobeline (Lobelia inflata), only one molecule of lysine is necessary, for quinolizidine alkaloids - e.g., lupinine (Lupinus luteus), sparteine of antiarrhythmic activity (Sarothamnus scoparius), and cytisine of respiratory stimulant effect (Laburnum species) - two molecules of lysines are indispensable. It was also proved that lycopodine (Lycopodium tristachyum, clubmoss) of quinolizidine structure has no polyketide origin, but it is a modified dimer of pelletierine, which, in turn, is derivable from lysine and acetate. 

It is interesting that anatabine was not derived from lysine, but nicotinic acid. (This alkaloid is characteristic for Nicotiana plants but was also detected in Lobelia inflata) (Fig. 11.21), [1]. 

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See also in sourсe #XX -- [ ]

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