Antiplasmodial alkaloids from Desmos rostrata.

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Pharmacognosy

Background:

• The stem bark of Desmos rostrata is a rich source of bioactive alkaloids.
• Alkaloids are a diverse class of natural products with a wide range of pharmacological activities.
• Investigating novel compounds from medicinal plants is crucial for drug discovery.

Purpose of the Study:

• To isolate and characterize new and known alkaloids from Desmos rostrata stem bark.
• To evaluate the cytotoxic and antimalarial activities of the isolated compounds.
• To explore the potential of these alkaloids as therapeutic agents.

Main Methods:

• Phytochemical investigation involving extraction and isolation techniques.
• Structure elucidation using spectroscopic methods such as mass spectrometry and 2D-Nuclear Magnetic Resonance (2D-NMR).
• In vitro bioassays to determine cytotoxicity against KB cells and inhibition of Plasmodium falciparum.

Main Results:

• Two new alkaloids, desmorostratine (1) and discretine N-oxide (2), were identified.
• Five known alkaloids: discretine (3), dehydrodiscretine (4), pseudocolumbamine (5), predicentrine (6), and aristolactam AII (7) were also isolated.
• Desmorostratine (1) demonstrated cytotoxicity against KB cells (IC50 2.4 µM).
• Discretine N-oxide (2), discretine (3), and dehydrodiscretine (4) exhibited significant inhibition against Plasmodium falciparum (IC50 4.2, 1.6, and 0.9 µM, respectively).

Conclusions:

• The study successfully isolated and characterized novel and known alkaloids from Desmos rostrata.
• The findings highlight the potential of desmorostratine as an anticancer agent and discretine N-oxide, discretine, and dehydrodiscretine as antimalarial leads.
• Further research is warranted to explore the therapeutic applications of these bioactive alkaloids.