Isolation and structural characterization of polycyclic diazepine alkaloids from Pandanus yvanii

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Phytochemistry

Background:

• Pandanus yvanii is a plant species known for its potential chemical constituents.
• Diazepine-containing alkaloids are a rare class of natural products with diverse biological activities.
• Exploring novel chemical scaffolds from plant sources is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize new alkaloids from Pandanus yvanii.
• To elucidate the structures of unprecedented polycyclic alkaloids.
• To investigate the structural diversity of diazepine-containing natural products.

Main Methods:

• Isolation of alkaloids using chromatographic techniques.
• Structure elucidation via comprehensive spectroscopic analyses (NMR, MS).
• Determination of absolute and relative configurations using ECD spectroscopy and computational methods (TDDFT, GIAO NMR, DP4+).

Main Results:

• Four novel polycyclic alkaloids, pandazepines A-D (1-4), were isolated.
• Pandazepines A and B are the first tetracyclic pyrrolidinoindoline-1,3-diazepine alkaloids.
• Pandazepines C and D possess unique pentacyclic fused-ring systems.
• Absolute and relative configurations were rigorously determined.

Conclusions:

• The discovery of pandazepines A-D significantly expands the known structural diversity of diazepine-containing natural products.
• These findings highlight the biosynthetic potential of the Pandanus genus.
• The study provides a foundation for further investigation into the biological activities and biosynthesis of these novel compounds.