Characterization and Antimicrobial Activity of Alkaloid Extracts from Seeds of Different Genotypes of Lupinus spp.

Alkaloid profiles of 22 lupin genotypes belonging to three different cultivated species, Lupinus albus L., Lupinus luteus L., and Lupinus angustifolius L., collected from different Italian regions and grown in Sicily, were studied by gas chromatography mass spectrometry (GC-MS) to determine alkaloid composition. More than 30 alkaloids were identified. The lowest alkaloid concentration was observed in the L. albus Luxor, Aster, and Rosetta cultivars, and in all the varieties of L. luteus and L. angustifolius. The highest content was observed in all the landraces of L. albus. Surprisingly, the white lupin Lublanc variety and the commercial seeds of cv Multitalia had a high alkaloid content. The tested species and the different genotypes exhibited different alkaloid profiles: lupanine, 13α-hydroxylupanine, and albine were the main alkaloids in the analyzed L. albus seeds; angustifoline and 13α-tigloyloxylupanine were well-represented in L. albus landraces; sparteine and lupinine were typical of L. luteus; and lupanine, 13α-hydroxylupanine, and angustifoline were the main alkaloids in L. angustifolius seeds. The samples with the highest amounts of total alkaloids proved to be interesting from a pharmaceutical viewpoint. The alkaloid extracts showed significant activity on Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates.