A New Cyclic Hexapeptide and a New Isocoumarin Derivative from the Marine Sponge-Associated Fungus Aspergillus similanensis KUFA 0013

Abstract

A new isocoumarin derivative, similanpyrone C (1), a new cyclohexapeptide, similanamide (2), and a new pyripyropene derivative, named pyripyropene T (3) were isolated from the ethyl acetate extract of the culture of the marine sponge-associated fungus Aspergillus similanensis KUFA 0013. The structures of the compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compound 2 the stereochemistry of its amino acid constituents was determined by chiral HPLC analysis of the hydrolysate by co-injection with the d and l amino acids standards. Compounds 2 and 3 were evaluated for their in vitro growth inhibitory activity against MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A373 (melanoma) cell lines, as well as antibacterial activity against reference strains and the environmental multidrug-resistant isolates (MRS and VRE). Only compound 2 exhibited weak activity against the three cancer cell lines, and neither of them showed antibacterial activity.

Naturally Occurring Isocoumarins Derivatives from Endophytic Fungi: Sources, Isolation, Structural Characterization, Biosynthesis, and Biological Activities

“…It was postulated that 273 is also derived from the malonate-acetate pathway [28]. The pentaketide (I) cyclization and enolization produce 88.…”

Cytotoxic Natural Products from Marine Sponge-Derived Microorganisms

“…One fungal strain, Aspergillus similanensis KUFA0013, derived from the sponge Rhabdermia sp. (Similan Islands, Thailand) was found to produce a new cyclohexapeptide, similanamide ( 62 ) (Chart 10), which possessed in vitro weak inhibitory activity against breast adenocarcinoma MCF-7, non-small cell lung cancer NCI-H460, and melanoma A373 cell lines [37]. Chemical examination of Scopulariopsis bre v icaulis from the marine sponge Tethya aurantium (Limski Fjord, Croatia) afforded two novel cyclodepsipeptides: scopularides A ( 63 ) and B ( 64 ) (Chart 10).…”

New chiral stationary phases based on xanthone derivatives for liquid chromatography

“…Analytical and preparative enantiomer separations by chromatography and related techniques play more than ever a crucial role in the chemical industry and academic research . Over the years, liquid chromatography (LC) using chiral stationary phases (CSPs) has become a very helpful and highly applicable method for preparative resolution of racemates, determination of the enantiomeric purity in quality control, analysis of the stereochemistry of natural compounds, monitoring enantiomeric reactions, and for pharmacokinetic and environmental studies . LC can be considered the method of choice in analytical laboratories due to its high speed, sensitivity, and reproducibility.…”