Three Meroterpenes From the Mangrove Endophytic Fungus Phyllosticta sp. E2A1

Area of Science:

• Natural Product Chemistry
• Marine Microbiology
• Immunology

Background:

• Mangrove endophytic fungi are a rich source of structurally diverse secondary metabolites.
• Meroterpenes, compounds derived from both the mevalonate/DOXP and shikimate pathways, often exhibit unique biological activities.

Purpose of the Study:

• To isolate and characterize new meroterpenes from the mangrove endophytic fungus Phyllosticta sp. E2A1.
• To evaluate the isolated compounds for their potential to inhibit nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells.

Main Methods:

• Isolation and purification of compounds using chromatographic techniques.
• Structure elucidation employing Nuclear Magnetic Resonance (NMR) spectroscopy, High-Resolution Electrospray Ionization Mass Spectrometry (HR-ESI-MS), and single-crystal X-ray diffraction.
• Biological activity assessment using nitric oxide inhibition assays in RAW264.7 macrophages.

Main Results:

• Two new monoterpene-shikimate-conjugated meroterpenes, phyllostictones J (1) and K (2), were identified.
• A new sesquiterpene-shikimate-conjugated spirocyclic meroterpene, capitalensis E (3), was also isolated.
• Phyllostictones K (2) demonstrated inhibitory activity against nitric oxide production with an IC50 value of 10.8 µM.

Conclusions:

• The study successfully identified three novel meroterpenes from a mangrove endophytic fungus.
• Phyllostictones K represents a promising compound for further investigation in the context of inflammatory modulation.