New ester alkaloids from lupins (genus lupinus)

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Phytochemistry

Background:

• Lupinus species are known sources of alkaloids.
• Esterification of hydroxyl groups on lupin alkaloids can modify their properties.
• Characterization of alkaloid diversity is crucial for understanding plant biochemistry.

Purpose of the Study:

• To synthesize and characterize new ester alkaloids of 13-hydroxylupanine and 4-hydroxylupanine.
• To identify novel ester alkaloids in four Lupinus species.
• To expand the known chemical profile of lupin alkaloids.

Main Methods:

• Synthesis of ester derivatives using various carboxylic acids.
• Characterization using capillary gas-liquid chromatography.
• Mass spectrometry (Electron Ionization-Mass Spectrometry and Chemical Ionization-Mass Spectrometry) for structural elucidation.

Main Results:

• Successful synthesis of esters with acetic, propionic, butyric, isobutyric, valeric, isovaleric, tiglic, benzoic, and TRANS-cinnamic acids.
• Identification of new ester alkaloids, including 13-propyloxylupanine, 13-butyryloxylupanine, 13-isobutyryloxylupanine, and 4-tigloyloxylupanine in LUPINUS POLYPHYLLUS, L. ALBUS, L. ANGUSTIFOLIUS, and L. MUTABILIS.
• Confirmation of previously known ester alkaloids in the studied species.

Conclusions:

• The study successfully expanded the repertoire of known lupin ester alkaloids.
• New naturally occurring ester alkaloids were identified in diverse Lupinus species.
• The findings contribute to the understanding of alkaloid biosynthesis and chemical diversity in the Lupinus genus.