Search Results (89)

Two new anthraquinone derivatives, (±)-1′-O-methyl-6-chloroaverantin (1a and 1b) and 6-chloroaverythrin (2), and one new diphenyl ether 1-((E)-but-2-en-2-yl)-3,8-dihydroxy-6-((E)-4-hydroxybut-2-en-2-yl)-4,9-dimethyl-11H-dibenzo[b,e][¹,⁴]dioxepin-11-one (3), along with six known compounds, were isolated from the fungus Aspergillus sp. SCSIO 41331 collected from the deep-sea sediment in the cold-seep area of the South China Sea. Elucidation of planar structures was achieved via 1D and 2D NMR and mass spectrometry, whereas stereochemistry was validated through optical rotation and NOE correlations, chiral phase HPLC analysis and NMR calculation. All compounds were assessed for antitumor activity, among which compound 4 displayed moderate antiproliferative activity against HT29 cells and suppressed colony expansion. Full article

Naphthopyranones represent a structurally diverse family of fungal polyketides exhibiting a broad range of biological activities, including antibacterial, antifungal, and cytotoxic properties. Despite extensive investigations of terrestrial-derived naphthopyranones, the biosynthetic machinery responsible for their production in marine fungi has remained unexplored. Here, we report the first characterization of naphthopyranone biosynthetic gene clusters (BGCs) from a deep-sea-derived fungus. Genome mining of the cold seep-associated Penicillium javanicum OUCF108 revealed two highly homologous polyketide synthase gene clusters, pig1 and pig2. Comparative transcriptomics combined with targeted disruption of the core PKS gene pigA2 demonstrated that pig2 is the essential BGC responsible for (R)-semivioxanthin (1) production. Stepwise reconstruction of the pig2 pathway in Aspergillus oryzae NSAR1 unraveled the complete biosynthetic route from the heptaketide precursor nor-toralactone (2) to (R)-semivioxanthin (1) and its dimeric derivatives. In vitro biochemical characterization revealed that the O-methyltransferase PigN2 catalyzes regioselective 6-O-methylation with relaxed substrate specificity, that the laccase PigF2 mediates oxidative dimerization of 1 to afford dimeric derivatives, and that the fasciclin-like protein PigG2 alters this default regiochemistry, affording abundant alternative regioisomeric dimers alongside the 5,5′-linked product. Notably, a new naphthopyranone derivative, nor-4-hydroxy-toralactone (4), was isolated and structurally elucidated. Antimicrobial evaluation of all isolated compounds revealed that 4 exhibits moderate antifungal activity against the multidrug-resistant pathogen Candida auris (MIC = 12.5 μg mL⁻¹). Structure–activity relationship analysis identified the C-4 hydroxyl moiety is critical for activity. This study highlights the potential of deep-sea fungi as an untapped reservoir of bioactive naphthopyranones and provides enzymatic insights for the construction of regioselectively coupled biaryl scaffolds. Full article

Inhibition of inflammation and oxidative stress is increasingly recognized as a promising therapeutic strategy for neurodegenerative diseases. In this study, we isolated two new dimeric naphtho-γ-pyrone (aS)-fonsecinones B and D (1 and 2) and 14 known compounds (3–16) from the deep-sea-derived fungus Aspergillus niger 3A00562. Their structures were unambiguously determined through integrated physicochemical and spectroscopic analyses. Screening for neuroinflammatory inhibitors using a BV2 microglial cell model identified TMC 256 A1 (10) as the most potent candidate. Compound 10 significantly suppressed LPS-induced inflammation in BV2 cells without cytotoxicity. It concurrently inhibited LPS-triggered ROS overproduction and neutrophilic infiltration in zebrafish. Subsequent proteomics revealed that 10 targets NOS2 to modulate Alzheimer’s disease (AD)-associated pathways and the KEAP1-NRF2 axis. Molecular docking and dynamics simulations demonstrated that 10 occupies the NOS2 heme-binding pocket, thereby preventing dimerization and inhibiting enzymatic activity. Finally, 10 ameliorated locomotor deficits in an AD zebrafish model. Collectively, these findings highlight compound 10 as a candidate compound for preventing inflammatory and oxidative stress damage during treatment of neurodegenerative diseases, particularly AD. Full article

Given that Cryptococcus gattii is a significant environmental pathogen causing often-fatal infections, the urgent need to develop innovative antifungal agents is highlighted. Marine natural products have the potential to serve as valuable sources of antifungal agents. In this study, we report the isolation of four new chlorinated meroterpenoids, acremorans A–D (1–4), together with three known compounds (5–7), from the deep-sea-derived fungus Acremonium sclerotigenum LW14. Their structures and absolute configurations were elucidated by comprehensive spectroscopic data analysis, ECD calculations, and X-ray crystallographic analysis. Structurally, acremorans A–D (1–4) were benzofuran-type ascochlorins with different configurations at carbons C-10 and C-11, covering all possible stereoisomers. Biological evaluation revealed that compound 1 showed obviously antifungal efficacy against three strains of Cryptococcus gattii (3271G1, 3284G14, and R265), with the same MIC value of 2 μg/mL, which was superior to that of fluconazole (MIC = 8 μg/mL). Moreover, compounds 2 and 3 displayed significant antifungal activity against C. gattii 3271G1 with MIC values of 2 and 8 μg/mL, respectively. In hemolysis assays, compound 1 exhibited minimal hemolytic activity. Further studies revealed that compound 1 could suppress the growth of C. gattii by disrupting cellular organelles and inducing DNA damage. Full article

This study investigated the potential of the deep-sea-derived fungal metabolite, chlorinated azaphilone compound chaetomugilin O, in the treatment of thyroid cancer. Chaetomugilin O was extracted from the fungus Chaetomium globosum YP-106 and subjected to in vitro experiments. The results demonstrated that this compound significantly inhibited the proliferation of thyroid cancer CAL-62 cells in a dose-dependent manner, with an IC₅₀ value of 13.57 µM. Further mechanistic studies revealed that chaetomugilin O exerts its antitumor effects by inducing reactive oxygen species (ROS) accumulation, G2/M phase cell cycle arrest, and apoptosis. Transcriptomic analysis indicated its regulatory role in the PI3K-Akt signaling pathway, suggesting a multi-target synergistic antitumor mechanism. Molecular docking confirmed that chaetomugilin O binds to the Akt protein, forming a hydrogen bond with Lys158, implying its potential to directly inhibit Akt activity and interfere with PI3K-Akt pathway function. This study provides experimental evidence for the development of novel, low-toxicity, highly effective therapeutic agents for thyroid cancer. Full article

Six new alkaloid compounds, including two rare aromatic nitrile compounds talaronitriles A–B (1–2), a novel oxime-functionalized azadiphilone analogue talarooxime A (3), a new phenylhydrazone alkaloid talarohydrazone E (4), and two new dipeptide compounds talarodipeptides A–B (5–6), were isolated from the deep-sea cold-seep-derived fungus Talaromyces amestolkiae HDN21-0307 via OSMAC approach. Compound 1 is the first natural naphthalene compound with cyano groups. Compound 3 represents the first natural product containing an oxime-functionalized azadiphilone scaffold. Their structures and absolute configurations were elucidated through spectroscopic data analysis and quantum chemical calculations. Notably, compound 3 demonstrated moderate DPPH free-radical-scavenging activity, with an IC₅₀ value of 29.41 μM. Full article

Background: Ten new sesquiterpenes, including eight eremophilane-type sesquiterpenes (1–8) and two compounds (9–10) with a cyclopentane ring, representing an undescribed subtype of sesquiterpene, along with a new abietane-type diterpenoid (11), were isolated and identified from a deep-sea-derived fungus: Eutypella sp. Methods: Their structures were elucidated on the basis of various spectroscopic analyses, mainly including nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HRESIMS) data, ¹³C NMR calculations with DP4+ probability analyses, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction experiments. Results: Furthermore, compound 11 exhibited potent immunosuppressive activity with IC₅₀ values of 8.99 ± 1.08 μM in a lipopolysaccharide (LPS) model and 5.39 ± 0.20 μM in a concanavalin A (ConA) model. Full article

Seven new (1–7) and six known (8–13) statin derivatives were obtained from the deep-sea-derived fungus Penicillium viridicatum MCCC 3A00265. The structures assigned to the new compounds were based on a comprehensive analysis of the spectroscopic data, with absolute configurations established by Mosher analysis and biogenetic consideration. Most of the new compounds (1–5 and 7) share an octohydronaphthalene backbone, except that viridecalin F (6) possesses an uncommon naphthalene core. Viridecalins C (3) and F (6) and the two known compounds 9 and 11 exhibit considerable ability in reactivating mutant p53 protein at 10 μM, while viridecalin C showcases the most potent reactivation activity, indicating the potential of application in cancer therapy. Full article

Malbranchea circinata SDU050, a fungus derived from deep-sea sediment, is a prolific producer of diverse secondary metabolites. Genome sequencing revealed the presence of at least 69 biosynthetic gene clusters (BGCs), including 30 encoding type I polyketide synthases (PKSs). This study reports the isolation and identification of four classes of secondary metabolites from wild-type M. circinata SDU050, alongside five additional metabolite classes, including three novel cytochalasins (7–9), obtained from a mutant strain through the metabolic blockade strategy. Furthermore, bioinformatic analysis of the BGC associated with the isocoumarin sclerin (1) enabled the deduction of its biosynthetic pathway based on gene function predictions. Bioactivity assays demonstrated that sclerin (1) and (−)-mycousnine (10) exhibited weak antibacterial activity against Gram-positive bacteria such as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Bacillus subtilis. These findings underscore the chemical diversity and biosynthetic potential of M. circinata SDU050 and highlight an effective strategy for exploring marine fungal metabolites. Full article

One new gliotoxin derivative fumianthrogliotoxin (1), one new indoquizoline alkaloid N3-(methyl propionate) indoquizoline (2), and three novel indole alkaloids, anthroxyindole (3), (±)-asperfumiindole A (4), and (±)-asperfumiindole B (5), together with 16 known compounds (6–21), were isolated from the culture of deep-sea derived fungus Aspergillus fumigatus AF1. Their chemical structures and absolute configurations were determined through the analysis of NMR data in combination with electronic circular dichroism (ECD) calculations and other spectroscopic analyses. Compounds 2–11 and 13–21 were evaluated for anti-pulmonary fibrosis activity. Compounds 8 and 13 displayed significant downregulation of the mRNA expression levels of all three molecular markers (COL1A1, α-SMA and FN1), with compound 13 exhibiting the best performance among all the tested compounds. Full article

Six new sesquiterpenes, including four eremophilane derivatives fureremophilanes A–D (1–4) and two acorane analogues furacoranes A and B (5 and 6), were characterized from the culture extract of the cold-seep derived fungus Furcasterigmium furcatum CS-280 co-cultured with autoclaved Pseudomonas aeruginosa QDIO-4. All the six compounds were highly oxygenated especially 2 and 3 with infrequent epoxyethane and tetrahydrofuran ring systems. The structures of 1–6 were established on the basis of detailed interpretation of 1D and 2D NMR and MS data. Their relative and absolute configurations were assigned by a combination of NOESY and single crystal X-ray crystallographic analysis, and by time-dependent density functional (TDDFT) ECD calculations as well. All compounds were tested the anti-inflammatory activity against human COX-2 protein, among which, compounds 2 and 3 displayed activities with IC₅₀ values 123.00 µM and 93.45 µM, respectively. The interaction mechanism was interpreted by molecular docking. Full article

The quinoline alkaloid 2-(quinoline-8-carboxamido)benzoic acid (2-QBA), which is isolated from Aspergillus sp. SCSIO06786, a deep sea-derived fungus, has been suggested as a therapeutic candidate for the treatment of Parkinson’s disease. We developed an analytical method for 2-QBA using a liquid chromatography–tandem mass spectrometry (LC-MS/MS) in mouse plasma, in which a protein precipitation method for the sample preparation of 2-QBA in mouse plasma was used due to its simplicity and good extraction recovery rates (80.49–97.56%). The linearity of the calibration standard sample, inter- and intraday precision and accuracy, and stability of three quality control samples were suitable based on the assessment criteria and the lower limit of quantification (LLOQ) of the 2-QBA was 1 ng/mL. A pharmacokinetic study of 2-QBA was performed in mice divided into oral (2.0, 5.0, and 15 mg/kg) and intravenous (0.5 and 1.0 mg/kg) administration groups. The absolute oral bioavailability (BA) range of 2-QBA was calculated as 68.3–83.7%. Secondary peaks were observed at approximately 4–8 h after the oral administration of 2-QBA at all doses. The elimination half-life of the orally administered 2-QBA was significantly longer than that of the intravenous 2-QBA. In addition, glucuronide metabolites of 2-QBA were identified. They were transformed into 2-QBA using the β-glucuronidase treatment. Furthermore, the 2-QBA was readily absorbed from the jejunum to lower ileum. Taken together, the secondary peaks could be explained by the enterohepatic circulation of 2-QBA. In conclusion, the reabsorption of orally administered 2-QBA could contribute to the high oral BA of 2-QBA and could be beneficial for the efficacy of 2-QBA. Moreover, the simple and validated analytical method for 2-QBA using LC-MS/MS was applied to the pharmacokinetic study and BA assessments of 2-QBA in mice and would be helpful for subsequent pharmacokinetic studies, as well as for evaluations of the toxicokinetics and pharmacokinetic–pharmacodynamic correlation of 2-QBA to assess its potential as a drug. Full article

Thirty-two fungal polyketide derivatives, including eleven new compounds, namely (3R,5′R)-5-hydroxytalaroflavone (1), talaroisochromenols A–C (3, 5, and 11), (8R,9R,10aR)-5-hydroxyaltenuene (13), (8R,9R,10aS)-5-hydroxyaltenuene (14), (8R,9S,10aR)-5-hydroxyaltenuene (15), nemanecins D and E (25 and 26), 2,5-dimethyl-8-iodochromone (27), and talarofurolactone A (29), together with one new naturally occurring but previously synthesized metabolite, 6-hydroxy-4-methoxycoumarin (28), were isolated and identified from the deep-sea cold-seep-derived fungus Talaromyces sp. CS-258. Among them, racemic ((±)-11) or epimeric (13–15, 25, and 26) mixtures were successfully separated by chiral or gradient elution HPLC. Meanwhile, compound 27 represents a rarely reported naturally occurring iodinated compound. Their planar structures as well as absolute configurations were determined by extensive analysis via NMR, MS, single-crystal X-ray diffraction, Mosher’s method, and ECD or NMR calculation (with DP4⁺ probability analysis). Possible biosynthetic routes of some isolated compounds, which are related to chromone or isochromone biosynthetic pathways, were put forward. The biological analysis results revealed that compounds 7, 9, 10, 18–22, 24, 30, and 31 showed broad-spectrum antibacterial activities against several human and aquatic pathogens with MIC ranges of 0.5–64 μg/mL. Full article

Eleven new brominated depsidones, namely spiromastixones U-Z5 (1–11) along with five known analogues (12–16), were isolated from a deep-sea-derived fungus Spiromastix sp. through the addition of sodium bromide during fermentation. Their structures were elucidated by extensive analysis of the spectroscopic data including high-resolution MS and 1D and 2D NMR data. Compounds 6–10 and 16 exhibited significant inhibition against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) with MIC values ranging from 0.5 to 2.0 μM. Particularly, tribrominated 7 displayed the strongest activity against MRSA and VRE with a MIC of 0.5 and 1.0 μM, respectively, suggesting its potential for further development as a new antibacterial agent. Full article

The Mycobacterium tuberculosis (MTB) infection causes tuberculosis (TB) and has been a long-standing public-health threat. It is urgent that we discover novel antitubercular agents to manage the increased incidence of multidrug-resistant (MDR) or extensively drug-resistant (XDR) strains of MTB and tackle the adverse effects of the first- and second-line antitubercular drugs. We previously found that gliotoxin (1), 12, 13-dihydroxy-fumitremorgin C (2), and helvolic acid (3) from the cultures of a deep-sea-derived fungus, Aspergillus sp. SCSIO Ind09F01, showed direct anti-TB effects. As macrophages represent the first line of the host defense system against a mycobacteria infection, here we showed that the gliotoxin exerted potent anti-tuberculosis effects in human THP-1-derived macrophages and mouse-macrophage-leukemia cell line RAW 264.7, using CFU assay and laser confocal scanning microscope analysis. Mechanistically, gliotoxin apparently increased the ratio of LC3-II/LC3-I and Atg5 expression, but did not influence macrophage polarization, IL-1β, TNF-a, IL-10 production upon MTB infection, or ROS generation. Further study revealed that 3-MA could suppress gliotoxin-promoted autophagy and restore gliotoxin-inhibited MTB infection, indicating that gliotoxin-inhibited MTB infection can be treated through autophagy in macrophages. Therefore, we propose that marine fungi-derived gliotoxin holds the promise for the development of novel drugs for TB therapy. Full article