Indolizidine alkaloids from Prosopis

Juliprosopine from Prosopis juliflora A. DC. is a new type of indolizidine alkaloid, and on the basis of an extensive spectroscopic and chemical study it has been assigned the structure (2), in which relative configurations are shown for the substituents on the piperidine ring. Juliprosopine may be derived biosynthetically from combination of a dihydropyrrole unit with two Prosopis piperidine alkaloids that have C12 side-chains.2... 

Juliprosopine (318) and juliprosine (319) (Fig. 5), indolizidine alkaloids of the genus Prosopis (mesquite family Leguminosae), had been partially characterized at the time of the previous review on the topic in this serial (7). Rather few advances have been made since then no further stereochemical clarification has been forthcoming, and no further work has been reported on two other putative Prosopis indolizidines, isojuliprosopine and isojuliprosine (295). However, the alkaloid juliflorine, previously isolated from Prosopis juliflora by workers from Pakistan (296,297), has since been shown to be identical to juliprosopine (298). 

Two further indolizidine alkaloids, juliprosinene ([a]o +9.5° for the chloride salt, c 0.04, CHCI3) and juliflorinine ([a]o +3.9°, c 0.03, CHCI3), were isolated from the leaves of Prosopis juUflora some years after the above work had been reported (299). Partial structures were once again deduced on the basis of extensive spectro-scopic comparisons with known alkaloids. Juliprosinene chloride, for instance, gave very similar spectra to juliprosine (319) and spectaline (320), and showed no doubling up... 

A series of substituted piperidine alkaloids have been isolated from the legume genera Cassia (subfamily Caesalpini-oideae) mdProsopis (subfamily Mimosoideae) (Fig. 29.16). (Strunz and Findlay, 1985). Based on the structures of these compounds, it seems possible that they are derived from acetate-malonate precursors. These compounds are quite similar in structure to the venoms of fire ants (Nahrstedt, 1982). Indolizidine alkaloids also have been isolated from Prosopis species (Howard and Michael, 1986). 

The unusual indolizidine alkaloid julisporine (39) from Prosopis juliflora (Fabaceae) possessed in vitro activity against several dermatophytic fungi (Clark and Hufford, 1992). 

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