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Sixteen metabolites, including seven C 7 -alkylated salicylaldehyde derivatives ( 1 - 7 ) and nine prenylated indole alkaloids ( 8 - 16 ), three of which are new, namely, asperglaucins A and B ( 1 and 2 ) and neoechinulin F ( 8 ), were separated from the endolichenic fungus Aspergillus chevalieri SQ-8. Asperglaucin A ( 1 ) represents an unusual phthalide-like derivative with a benzo[ c ]thiophen-1(3 H )-one scaffold. All compounds were assessed in vitro for antibacterial, antineuroinflammatory, and antioxidant activities. Notably, asperglaucins A and B exhibited potent antibacterial activities against two plant pathogens Pseudomonas syringae pv actinidae (Psa) and Bacillus cereus , with an MIC value of 6.25 μM; further SEM analyses illustrated that the possible bacteriostatic mechanisms for compounds 1 and 2 were to alter the external structure of B. cereus and Psa, and to cause the rupture or deformation of the cell membranes, respectively, and the results suggest that compounds 1 and 2 may serve as potential promising candidates for lead compounds of agrochemical bactericides. Furthermore, compounds 6 and 10 significantly inhibited nitric oxide production with an IC 50 value of ca. 12 μM, and the possible anti-inflammatory mechanisms involved were also studied by molecular docking. Finally, the tested phenolics 3 - 5 showed significant antioxidative effects. Thus, strain SQ-8 represents a novel resource of these bioactive metabolites to be utilized.

Tricrilactones A–H (1–8), a new family of oligomeric 10‐membered macrolides featuring collectively five unique ring skeletons, were isolated from a hitherto unexplored fungus, Trichocladium crispatum. Compounds 1 and 7 contain two unconventional bridged (aza)tricyclic core skeletons, 2, 3, 5, and 6 share an undescribed tetracyclic 9/5/6/6 ring system, 4 bears an uncommon 9/5/6/10/3‐fused pentacyclic architecture, and 8 is a dimer bridged by an unexpected C−C linkage. Their structures, including absolute configurations, were elucidated by spectroscopic analysis, quantum chemical calculations, and X‐ray diffraction analysis. Importantly, the absolute configuration of the highly flexible side chain of 1 was resolved by the asymmetric synthesis of its four stereoisomers. The intermediate‐trapping and isotope labeling experiments facilitated the proposal of the biosynthetic pathway for these macrolides. In addition, their antiosteoporosis effects were evaluated in vivo (zebrafish). [ABSTRACT FROM AUTHOR]

Two new sterpurane sesquiterpenoids named sterpurol D (1) and sterpurol E (2), and one skeletally new sesquiterpene, cryptomaraone (3), bearing a 5,6-fused bicyclic ring system, along with five known ones, sterpurol A (4), sterpurol B (5), paneolilludinic Acid (6), murolane-2α, 9β-diol-3-ene (7) and (–)-10,11-dihydroxyfarnesol (8) were isolated from an endolichenic fungus Cryptomarasmius aucubae. The structures of the new compounds were elucidated by analysis of NMR spectroscopic spectra and HRESIMS data. The absolute configurations of 1 and 2 were established by spectroscopic data analysis and comparison of specific optical rotation, as well as the biosynthetic consideration. Additionally, compounds 1, 2, 4–6, and 8 showed significant nitric oxide (NO) production inhibition in Lipopolysaccharide (LPS)-induced BV-2 microglial cells with the IC50 values ranging from 9.06 to 14.81 μM. [ABSTRACT FROM AUTHOR]

In this research, twenty aromatic and branched aliphatic polyketides, including seven previously undescribed butenolide derivatives, piterriones A–G and one known analogue, along with twelve known altenusin derivatives, were isolated from the isopod-associated fungus Pidoplitchkoviella terricola. Their structures were elucidated by analysis of NMR (1D and 2D) and mass spectrometry data, and their absolute configurations were determined by Mosher's method, microscale derivatization, and comparison of their specific rotations and ECD spectra. Dihydroaltenuene B exhibited mushroom tyrosinase inhibitory activity with an IC 50 value of 38.33 ± 1.59 μM, which was comparable to that of the positive control, kojic acid (IC 50 = 39.72 ± 1.34 μM). A molecular-docking study disclosed the hydrogen bonding interactions between the 3-OH and 4′-OH of dihydroaltenuene B and the His244, Met280 and Gly281 residues of tyrosinase. Seven undescribed butenolide derivatives, piterriones A–G were isolated from isopod-associated fungus Pidoplitchkoviella terricola. Dihydroaltenuene B exhibited mushroom tyrosinase inhibitory activity. [Display omitted] • Seven undescribed butenolide derivatives were isolated from the fungus Pidoplitchkoviella terricola. • Their absolute configurations were determined by Mosher's method and microscale derivatization. • This is the first report of the dihydroaltenuene B showing tyrosinase inhibitory activity. [ABSTRACT FROM AUTHOR]