New Isocoumarin Analogues from the Marine-Derived Fungus Paraphoma sp. CUGBMF180003

Abstract

Nine new secondary metabolites, including six isocoumarin analogues, 7-hydroxyoospolactone (1), 7-methoxyoospolactone (2), 7-methoxy-9-hydroxyoospolactone (3), 10-acetoxy-9-hydroxyoospolactone (4), 6-dehydroxysescandelin (5), parapholactone (6), and three compounds with a rare skeleton of isocoumarin coupled with phenylethylamine, namely paraphamide A (12), paraphamide B (13), and paraphamide C (14), together with five known compounds, oospolactone (7), 8-O-methyloospolactone (8), 10-hydroxyoospolactone (9), 9,10-dihydroxyoospolactone (10), and oospoglycol (11), were isolated and identified from the marine-derived fungus Paraphoma sp. CUGBMF180003. Their chemical structures were determined using spectroscopic data, including HRESIMS and 1D and 2D NMR techniques. Furthermore, the stereogenic carbons in 5 and 14 were determined by comparing the experimental and calculated electronic circular dichroism (ECD) spectra. The carbon skeleton of 12–14 was identified as the first example of isocoumarin coupled with phenylethylamine derivatives. All of these compounds were examined for antimicrobial activities against Candida albicans and Staphylococcus aureus. Both 1 and 6 showed antibacterial activity against S. aureus with MIC values of 12.5 μg/mL.

New Secondary Metabolites from the Marine-Derived Fungus Talaromyces mangshanicus BTBU20211089

“…The molecular formula of 1 was determined to be C19H24N2O5S based on the HRESIMS spectrum (m/z [M + H] + 393.1481, calcd for C19H25N2O5S, 393.1479), accounting for nine degrees of unsaturation (Figure S1). The 1 H NMR, 13 C, and HSQC spectra of 1 (Figures S2-S4, Table 1…”

“…The molecular formula of 1 was determined to be C 19 H 24 N 2 O 5 S based on the HRESIMS spectrum (m/z [M + H] + 393.1481, calcd for C 19 H 25 N 2 O 5 S, 393.1479), accounting for nine degrees of unsaturation (Figure S1). The 1 H NMR, 13 C, and HSQC spectra of 1 (Figures S2-S4, Table 1 shifts of C-5, C-12, and C-14 and the molecular formula, C-5 and C-16 were linked by a sulfur atom to form the tetrahydrothiophene moiety of ring B, and C-12 and C-14 were linked by an oxygen atom to form the dihydrofuran moiety of ring D. Therefore, the planar structure of 1 was assigned. The absolute configurations of 1 were established as 5S, 8R, 12S, and 16S by comparing the experimental and calculated ECD spectra (Figure 3).…”

“…During our ongoing investigations into bioactive natural products from marinederived microorganisms [10][11][12][13], a fungal strain of Talaromyces mangshanicus BTBU20211089, which was isolated from a sediment sample collected from the South China Sea, was found to be active against Candida albicans. Chemical investigation of this fungus cultured in rice solid media led to the isolation and identification of seven new compounds, namely, talaromanloid A (1), talaromydene (2), 10-hydroxy-8-demethyltalaromydine and 11-hydroxyd-8-emethyltalaromydine (3 and 4), talaromylectone (5), and ditalaromylectones A and B (6 and 7), together with seven known compounds.…”

“…Chemical investigation of this fungus cultured in rice solid media led to the isolation and identification of seven new compounds, namely, talaromanloid A (1), talaromydene (2), 10-hydroxy-8-demethyltalaromydine and 11-hydroxyd-8-emethyltalaromydine (3 and 4), talaromylectone (5), and ditalaromylectones A and B (6 and 7), together with seven known compounds. The known compounds were determined to be 3-(propan-2-ylidene)-pyrrolidine-2, 5-dione (8) [14], (E)-3-(2,5-dioxo-3-(propan-2-ylidene)pyrrolidin-1-yl)acrylic acid (9) [15], nafuredin (10) [16], dehydroaustinol (11) [17], austinolide (12) [18], altenusin (13), and 5 -methoxy-6-methyl-biphenyl-3,4,3 -triol (14) [19] (Figure 1). Here, we report the isolation, structure elucidation, and bioactivities of these compounds.…”

“…Here, we report the isolation, structure elucidation, and bioactivities of these compounds. droaustinol (11) [17], austinolide (12) [18], altenusin (13), and 5′-methoxy-6-methyl-biphenyl-3,4,3′-triol ( 14) [19] (Figure 1). Here, we report the isolation, structure elucidation, and bioactivities of these compounds.…”