Two New Pentadepsipeptides from the Mangrove Fungus Aspergillus sp. SCSIO 41443

Background: Mangrove fungi are a prolific source of structurally diverse natural products. Among these, natural peptides with varied biological activities hold high commercial value and have been successfully developed into drugs for treating numerous diseases. Methods: Following rice solid-state fermentation of the strain, extracellular metabolites were extracted from the culture filtrate to obtain a crude extract. Cyclic depsipeptides were isolated from the crude extract by silica gel vacuum liquid chromatography for preliminary fractionation and enrichment, followed by high-performance liquid chromatography (HPLC) purification. The structures of the compounds were determined based on extensive spectroscopic analysis (1D and 2D NMR, ESI-MS-MS analysis) and Marfey's method for amino acid configuration assignment. Results: Ultimately, two new compounds, aspertides F (1) and G (2), and three known compounds, aspertides C, D, and A (3-5), were identified. The bioassays indicated that these compounds exhibited weak activity against acetylcholinesterase and neuraminidase. Conclusions: The research findings on this strain have not only enriched the metabolic resource library of mangrove fungi but also highlighted their diverse biological activities and significant application potential.