Sesquiterpenes from the Endophyte Glomerella cingulata

Area of Science:

• Natural Product Chemistry
• Pharmacology
• Mycology

Background:

• The toxic plant Gelsemium elegans harbors endophytic fungi with potential for novel metabolite discovery.
• Endophytic fungi are a rich source of structurally diverse and biologically active compounds.

Purpose of the Study:

• To isolate and characterize new chemical compounds from the endophytic fungus Glomerella cingulata.
• To evaluate the anti-inflammatory potential of the isolated compounds by assessing their effect on nitric oxide production.

Main Methods:

• Isolation of endophytic fungus Glomerella cingulata from Gelsemium elegans.
• Structure elucidation of isolated compounds using spectroscopic methods (e.g., NMR, MS).
• Determination of absolute configurations using Electronic Circular Dichroism (ECD) calculations.
• In vitro assay for nitric oxide inhibition in LPS-stimulated BV2 cells.

Main Results:

• One new phenanthrene (1) and four new sesquiterpenes (2-5) were isolated, along with three known sesquiterpenes (6-8).
• The structures and absolute configurations of the new compounds were successfully determined.
• Compounds 2, 4, and 5 demonstrated significant inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 cells at 1 μM concentration.

Conclusions:

• Glomerella cingulata, an endophyte of Gelsemium elegans, produces novel phenanthrene and sesquiterpene derivatives.
• The isolated sesquiterpenes possess anti-inflammatory properties, evidenced by their ability to inhibit NO production.
• These findings highlight the potential of endophytic fungi as a source for discovering new anti-inflammatory natural products.