Monoterpene indole alkaloids from Rhazya stricta

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Pharmacognosy

Background:

• Rhazya stricta is a plant source of bioactive natural products.
• Monoterpene indole alkaloids (MIAs) are a diverse class of plant-derived compounds with various biological activities.
• Investigating the chemical constituents of R. stricta can lead to the discovery of novel bioactive molecules.

Purpose of the Study:

• To isolate and characterize monoterpene indole alkaloids (MIAs) from Rhazya stricta.
• To identify new MIA structures and elucidate their chemical properties.
• To evaluate the antifungal activities of the isolated compounds against pathogenic Candida species.

Main Methods:

• Phytochemical investigation involving extraction and isolation techniques.
• Structure elucidation using High-Resolution Mass Spectrometry (HRMS) and Nuclear Magnetic Resonance (NMR) spectroscopy.
• Antifungal activity screening using broth microdilution assays to determine Minimum Inhibitory Concentrations (MICs).

Main Results:

• Twenty-seven MIAs, including three previously undescribed compounds, were successfully isolated from Rhazya stricta.
• The novel compound Secopleiocarpamine A (1) was identified as a unique 2,3-seco pleiocarpamine type MIA containing a cyano group.
• Compounds 2, 5, 12, 21, 23, and 27 demonstrated moderate inhibitory activity against six Candida strains, with MIC values between 3.125 and 50 μg/mL.

Conclusions:

• The phytochemical analysis of Rhazya stricta yielded a diverse array of MIAs, expanding the known chemical diversity of this plant.
• The discovery of Secopleiocarpamine A provides insights into novel MIA structural types and potential biosynthetic pathways.
• Several isolated MIAs exhibit promising antifungal properties, warranting further investigation for potential therapeutic applications against Candida infections.