Chemotaxonomic significance of alkaloids in the genus Lebeckia

The alkaloids of fourteen species of Lebeckia have been identified. Sparteine, lupanine and nuttalline were found to be the major alkaloids of all the species studied. α-isolupanine and a novel alkaloid 3β,4α-dihydroxylupanine (lebeckianine) were identified as minor compounds. Lebeckia differs from other quinolizidine-bearing genera of the tribe Crotalarieae by the absence of α-pyridone alkaloids and esters of alkaloids. The combination of major alkaloids seems to be a useful chemotaxonomic marker for the genus and agrees with suggestions that Lebeckia is one of the basal groups in the tribe. Despite morphological dissimilarities, species from different sections of the genus are remarkably similar in their alkaloidal constituents.