[Amaryllidaceae alkaloids from Lycoris radiata]

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Medicinal Chemistry

Background:

• Lycoris radiata is a plant species known for its diverse alkaloid content.
• Previous research has identified various bioactive compounds from this genus.
• Understanding the specific alkaloid profile of L. radiata bulbs is crucial for potential applications.

Purpose of the Study:

• To isolate and characterize alkaloids from the bulbs of Lycoris radiata.
• To identify novel alkaloid compounds and those not previously reported in this plant species.
• To contribute to the knowledge of Lycoris radiata phytochemistry.

Main Methods:

• Extraction of Lycoris radiata bulbs using 70% ethanol.
• Fractionation of the extract using a chloroform-soluble fraction.
• Isolation and purification of alkaloids via various column chromatographies (silica gel, ODS, Sephadex LH-20, MCI).
• Structure elucidation using chemical and physicochemical properties and spectroscopic data (NMR, MS, etc.).

Main Results:

• Nine alkaloids were isolated and identified: three aporphine-type (1-3), three lycorine-type (4-6), two crinane-type (7, 8), and one phenanthridine-type (9).
• Compound 1, (+)-N-methoxylcarbonyl-1,2-methylenedioxyl-isocorydione, was identified as a new compound.
• Alkaloids 2-9, including isocorydione, 8-demethyl-dehydrocrebanine, (+)-3-hydroxy-anhydrolycorine N-oxide, vasconine, pancratinine D, yemenine A, 11-O-acetylhaemanthamine, and 5,6-dihydro-5-methyl-2-hydroxyphenanthridine, were isolated from L. radiata for the first time.

Conclusions:

• The study successfully isolated and identified a range of alkaloids from Lycoris radiata bulbs.
• The discovery of a new compound and the first-time identification of several known alkaloids in this plant expand the known chemical diversity of L. radiata.
• These findings provide a basis for further investigation into the biological activities and potential applications of these isolated alkaloids.