Six new indole alkaloids including five new glyantrypine derivatives (1, 2a, 2b, 3, 4) and a new pyrazinoquinazoline derivative (5), together with eight known alkaloids (6-13), were isolated from the culture of the mangrove-derived fungus Cladosporium sp. PJX-41. Their structures were elucidated primarily by spectroscopic and physical data. The absolute configurations of compounds 1-9 were established on the basis of CD, NOESY data, and single-crystal X-ray diffraction analysis. Compounds 2b, 5, 7-9, and 11 exhibited significant activities against influenza virus A (H1N1), with IC50 values of 82-89 μM.
Six unusual xanthone-chromanone dimers, versixanthones A-F (1-6), featuring different formal linkages of tetrahydroxanthone and 2,2-disubstituted chroman-4-one monomers, were isolated from a culture of the mangrove-derived fungus Aspergillus versicolor HDN1009. The absolute configurations of 1-6, representing the central and axial chirality elements or preferred helicities, were established by a combination of X-ray diffraction analysis, chemical conversions, and TDDFT-ECD calculations. The interconversion of different biaryl linkages between 1 and 4 and between 2 and 3 in DMSO by a retro-oxa-Michael mechanism provided insight into the formation of the xanthone-chromanone dimers and supported the assignments of their absolute configurations. Compounds 1-6 exhibited cytotoxicities against the seven tested cancer cell lines, with the best IC50 value of 0.7 μM. Compound 5 showed further inhibitory activity against topoisomerase I.
Two novel sorbicillinoids combining a bicyclo[2.2.2]octane with a 2-methoxyphenol moiety, named sorbicatechols A (1) and B (2), were isolated from the culture of the marine sediment-derived fungus Penicillium chrysogenum PJX-17, together with the known protocatechuic acid methyl ester and caffeic acid methyl ester (3). Their structures, including absolute configurations, were assigned by analysis of NMR, MS data, and TDDFT ECD calculations. Compounds 1 and 2 exhibited activities against influenza virus A (H1N1), with IC50 values of 85 and 113 μ M, respectively.
Four new alkyl aromatics, penixylarins
A–D (1–4), along with the
known biogenetically related
1,3-dihydroxy-5-(12-hydroxyheptadecyl)benzene (5) and
1,3-dihydroxy-5-(12-sulfoxyheptadecyl)benzene (6), were
isolated from a mixed culture of the Antarctic deep-sea-derived fungus Penicillium crustosum PRB-2 and the mangrove-derived fungus Xylaria sp. HDN13-249. UPLC-MS data and an analysis of structural
features showed that compounds 1 and 2 were
produced by collaboration of the two fungi, while compounds 3–6 could be produced by Xylaria sp. HDN13-249 alone, but in noticeably increased quantities by cocultivation.
Compounds 2, 3, 5, and 6 showed antibacterial activity against a panel of strains,
and compound 3 possessed potential antituberculosis effects
(MIC = 6.25 μM against Mycobacterium phlei).
Four new cyclic peptides, psychrophilins E-H (1-4), possessing a rare amide linkage between the carboxylic acid in anthranilic acid (ATA) and the nitrogen from an indole moiety, along with a new ATA-containing hexapeptide, versicotide C (5), were obtained from the culture of the marine-derived fungus Aspergillus versicolor ZLN-60. The structures, including absolute configurations, were elucidated by a combination of HRESIMS, NMR, X-ray crystallography, TDDFT ECD calculations, and Marfey's method. Versicotide C (5) is the first natural cyclic hexapeptide containing two anthranilic acids. Compounds 1-5 were not cytotoxic, and compound 3 showed potent lipid-lowering effects.
Three new citrinin analogues, penicitols A-C (1-3), and one new xanthone derivative, penixanacid A (4), together with four known biogenetically related compounds (5-8), were discovered from the extract of a mangrove-derived fungus, Penicillium chrysogenum HND11-24. The structures of penicitols A-C and penixanacid A were established through analysis of extensive spectroscopic data. Their cytotoxic activity against HeLa, BEL-7402, HEK-293, HCT-116, and A549 cell lines was evaluated.
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