A series of meroterpenoids with highly oxygenated skeletons from the endophytic fungus Penicillium sp. and their anti-inflammatory activities

Four undescribed meroterpenoids, peniclactone D (1) and penichrodrimanins A-C (5-7), along with five known analogues (2-4, 8, and 9), were isolated from the fungus Penicillium sp. GDGJ-285. Their structures and absolute configurations were established on the basis of spectroscopic analyses and single-crystal X-ray diffraction. Compound 1 represents a highly oxygenated 6/5/6/5/5/5 polycyclic ring system, and 7 is a chrodrimanin-type meroterpenoid with a rare ether linkage between rings A and B via C-3 and C-9. Compound 5 exhibited notable inhibitory effect on nitric oxide (NO) production in LPS-induced RAW 264.7 cells, with the IC50 value of 18.50 ± 1.26 μM compared to dexamethasone (33.61 ± 4.45 μM). The further investigation indicated that 5 could suppress LPS-induced TNF-α, IL-1β, and iNOS expression via inhibition of NF-κB signaling pathway.

Anti-neuroinflammatory naphthol dimers from the marine-derived fungus Penicillium sp. HQ1-23

Five undescribed naphthol dimers, penibinaphthols A-E (1-5), and two known analogues (6 and 7), were isolated from the marine-derived fungus Penicillium sp. HQ1-23. Their structures were elucidated based on spectroscopic data analysis, and the absolute configurations were determined by X-ray crystallographic data and ECD spectroscopic analysis. Compound 3, with a ketone carbonyl group at C-1', potently inhibited LPS-induced NO production in BV-2 microglial cells (IC50 = 6.86 ± 0.10 μM), surpassing that of the positive control minocycline (IC50 = 23.57 ± 0.92 μM). Moreover, compound 3 decreased LPS-induced iNOS and COX-2 expression and reduced LPS-stimulated levels of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6.

Cytotoxic metabolites from the mangrove endophytic fungus Aspergillus sp. GXNU QG1a

A new benzoquinone, guxiumasperone A (1), and a new diisoprenyl-cyclohexene-type meroterpenoids, biscognienyne M (2), along with four known diisoprenyl-cyclohexene analogues was isolated from the mangrove endophytic fungus Aspergillus QG1a. Their structures were determined by extensive spectral analysis of 1D and 2D NMR, HR-ESI- MS, and X-ray crystallography. Compound 1 was deduced by a single-crystal X-ray diffraction analysis, and the absolute configuration of 2 was further unequivocally elucidated by comparing the experimental electronic circular dichroism (ECD) data with calculated ECD spectra. Compounds 1 and 2 showed significant cytotoxic activity against selected tumour cells. Particularly, compound 2 exhibited strong activity against A2780 cancer cells with an IC50 value of 6.8 μM.

Two new cytochalasins from the endophytic fungus Xylaria sp. GDGJ-77B

Two new open-chain cytochalasins, xylarchalasins A and B (1 and 2), together with six known analogues (3-8), were isolated from the endophytic fungus Xylaria sp. GDGJ-77B from the Chinese medicinal plant Sophora tonkinensis. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. Compound 2 displayed moderate antibacterial activities against Bacillus subtilis and Escherichia coli with MIC values of 25 and 12.5 μg/mL, respectively.

Austin-Type Meroterpenoids from Fungi Reported in the Last Five Decades: A Review

Austin was first isolated as a novel polyisoprenoid mycotoxin from Aspergillus ustus in 1976. Subsequently, some new austin-type meroterpenoids (ATMTs) have been continually found. This review attempts to give a comprehensive summary of progress on the isolation, chemical structural features, biological activities, and fungal biodiversity of 104 novel ATMTs from 5 genera of terrestrial- and marine-derived fungi reported from October 1976 to January 2023. The genera of Penicillium and Aspergillus are the two dominant producers, producing 63.5% and 30.8% of ATMTs, respectively. Moreover, about 26.9% of ATMTs display various pronounced bioactivities, including insecticidal, anti-inflammatory, cytotoxicity, antibacterial, and PTP1B inhibitory activities. The chemical diversity and potential activities of these novel fungal ATMTs are reviewed for a better understanding, and a relevant summary focusing on the source fungi and their taxonomy is provided to shed light on the future development and research of austin-type meroterpenoids.

Isolation and Characterization of Antimicrobial Metabolites from the Sophora tonkinensis-Associated Fungus Penicillium sp. GDGJ-N37

Chemical investigation of Penicillium sp. GDGJ-N37, a Sophora tonkinensis-associated fungus, yielded two new azaphilone derivatives, N-isoamylsclerotiorinamine (1) and 7-methoxyl-N-isoamylsclerotiorinamine (2), and four known azaphilones (3-6), together with two new chromone derivatives, penithochromones X and Y (7 and 8). Their structures were elucidated based on spectroscopic data, CD spectrum, and semi-synthesis. Sclerotioramine (3) showed significant antibacterial activities against B. subtilis and S. dysentery, and it also showed most potent anti-plant pathogenic fungi activities against P. theae, C. miyabeanus, and E. turcicum.

Cycloaspeptide H, a cyclopentapeptide from the endophytic fungus Penicillium virgatum

One new cyclopentapeptide, cycloaspeptide H (1), featuring a serine residue, along with seven known compounds (2-8), was isolated from the endophytic fungus Penicillium virgatum GDGJ-227. The planar structure of 1 was elucidated by a comprehensive analysis of NMR and MS spectroscopic spectra, and the absolute configuration was determined by single-crystal X-ray diffraction (Cu Kα) analysis. Compounds 7 and 8 displayed antibacterial activities against Bacillus subtilis and Enterobacter aerogenes with MIC values ranging from 12.5 to 50 μg/mL.

Isolation and insecticidal activities of new cyclic peptides from mangrove endophytic fungus Aspergillus sp. GXNU-4QQY1a

An investigation on bioactive metabolites from the mangrove endophytic fungus Aspergillus sp. GXNU-4QQY1a led to the isolation of two undescribed cyclic peptides, guaspertide A (1) and guaspertide B (2), together with six known compounds, 3-8. These structures and the new compounds' absolute configuration were determined by mass spectrometry analysis, nuclear magnetic resonance spectrum, electronic circular dichroism, and single-crystal X-ray diffraction. Insecticidal assays were carried out with compounds 1-8, and the results showed that compounds 1-3 and 8 exhibited good insecticidal activity against citrus psyllids.

Peniandranoids A-E: Meroterpenoids with Antiviral and Immunosuppressive Activity from a Penicillium sp

Peniandranoids A-E (1-5), five new meroterpenoids, together with three known analogues (6-8), were isolated from the fermentation of a soil-derived fungus, Penicillium sp.sb62. Their structures including absolute configurations were determined by extensive spectroscopic analysis, and the absolute configurations of compounds 1 and 5 were further elucidated by single-crystal X-ray diffraction. Peniandranoids A-E belong to a rare class of andrastin-type meroterpenoids incorporating an extra polyketide unit (a C₁₀ polyketide unit for 1 and 2, a C₉ polyketide unit for 3 and 4, and a furancarboxylic acid unit for 5). Compounds 1 and 6 exhibited favorable inhibitory activities against influenza virus A (H1N1) with EC₅₀ values of 19 and 14 μg/mL, respectively. Compounds 3-8 exhibited potent immunosuppressive activities against concanavalin A-induced T cell proliferation with EC₅₀ values ranging from 4.3 to 27 μM and lipopolysaccharide-induced B cell proliferation with EC₅₀ values ranging from 7.5 to 23 μM, respectively.

Talaromynoids A-I, Highly Oxygenated Meroterpenoids from the Marine-Derived Fungus Talaromyces purpureogenus SCSIO 41517 and Their Lipid Accumulation Inhibitory Activities

Nine new highly oxygenated 3,5-dimethylorsellinic acid-derived meroterpenoids, talaromynoids A-I (1-9), were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures including absolute configurations were elucidated by HRMS, NMR, single-crystal X-ray diffraction analysis, and electronic circular dichroism calculations. Compounds 1 and 7-9 possessed unprecedented 5/7/6/5/6/6, 6/7/6/6/6/5, 6/7/6/5/6/5/4, and 7/6/5/6/5/4 polycyclic systems, respectively. Biologically, compound 5 showed selective inhibitory activity against phosphatase CDC25B with an IC₅₀ value of 13 μM. Moreover, 7-9 and 12 exhibited the activity of reducing triglyceride in 3T3-L1 adipocytes in a dosage-dependent manner.

Hot off the Press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as neopetrothiazide from a Neopetrosia species.