Distribution and taxonomic significance of major alkaloids in the genus Podalyria

A chemotaxonomic survey of alkaloids in 22 species of the genus Podalyria has shown the presence of several different tetracyclic quinolizidine alkaloids and their angelate, tigliate and carboxylic acid esters. Quantitative and qualitative differences were found between the species and also between samples of twigs, leaves, pods and seeds. Most of the species have high concentrations of lupanine as virtually the only alkaloid, but some have a wide range of different compounds, including various hydroxylated lupanines and esters of alkaloids. The three yellow-flowered species differ from all others in the presence of virgiline, oroboidine and virgiline-pyrrolyl carboxylic acid ester as major alkaloids. These three compounds were found to be totally absent in all the pink- and white-flowered species of the genus. In the tribe Podalyrieae, carboxylic acid esters were hitherto known only from the genus Virgilia and their distribution agrees with morphological evidence that the yellow-flowered group of species should be excluded from Podalyria.