Bioactive indole alkaloids from insect derived endophytic Aspergillus lentulus.

Area of Science:

• Natural Products Chemistry
• Mycology
• Medicinal Chemistry

Background:

• Endophytic fungi are a promising source for novel bioactive compounds.
• Fungal secondary metabolites, particularly indole alkaloids, often exhibit significant biological activities.
• Aspergillus lentulus is an under-explored endophytic fungus with potential for chemical discovery.

Purpose of the Study:

• To isolate and characterize new bioactive compounds from an endophytic Aspergillus lentulus strain.
• To evaluate the cytotoxic and antibacterial potential of the isolated compounds.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation via comprehensive spectroscopic analyses (1D/2D NMR, HR-ESI-MS).
• Determination of absolute configurations using electronic circular dichroism (ECD) calculations and experiments.

Main Results:

• Three new indole alkaloids (compounds 1-2, 4) and twelve known compounds were identified.
• Compounds 2, 4, 5, 13, and 15 demonstrated moderate cytotoxicity against A549 cells (IC50: 17.92–48.29 μM).
• Compounds 1, 2, and 13-15 exhibited antibacterial activity against Xanthomonas oryzae pv. oryzae and pv. oryzicola (MIC: 25–100 μg/mL).

Conclusions:

• The endophytic fungus Aspergillus lentulus produces structurally diverse indole alkaloids.
• The isolated compounds possess potential as cytotoxic and antibacterial agents.
• Further investigation into these compounds may lead to the development of new therapeutic agents.