Indole alkaloids from Geissospermum reticulatum.

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Pharmacology

Background:

• Geissospermum reticulatum is a plant source of indole alkaloids.
• Indole alkaloids possess diverse biological activities.
• Characterizing novel natural products is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize indole alkaloids from Geissospermum reticulatum.
• To evaluate the antiparasitic activities of these alkaloids.
• To discover new therapeutic leads for parasitic diseases.

Main Methods:

• Isolation of alkaloids using chromatographic techniques.
• Structure elucidation via 1D and 2D NMR spectroscopy and X-ray crystallography.
• Antiparasitic activity screening against Trypanosoma cruzi and Leishmania infantum.

Main Results:

• Ten indole alkaloids were isolated; seven from leaves and three from bark.
• Seven aspidospermatan-type alkaloids were identified, including a novel geissospermidine subtype.
• Compounds 1-3, 5-8, and 10 were new natural products; 4 and 9 were known.
• Extracts and pure alkaloids showed selective antiparasitic activity, particularly against Leishmania infantum.
• O-demethylaspidospermine (alkaloid 4) demonstrated high activity against Leishmania infantum.

Conclusions:

• Geissospermum reticulatum is a rich source of structurally diverse indole alkaloids.
• Novel indole alkaloids, including the geissospermidine subtype, were characterized.
• The study identified potential antiparasitic agents, with O-demethylaspidospermine being a promising candidate for treating Leishmania infections.