Search Results (333)

Indane and phenylpropyl derivatives are interesting precursors for the synthesis of bioactive compounds, including those with antifungal or anti-inflammatory properties. In light of the increasing interest in the biocatalytic potential of marine-derived fungi, a study was conducted in which the substrates indene (1), indanone (2), 5-chloroindanone (2a), 1-phenylpropyl acetate (3), and 1-(4′-chlorophenyl)propyl acetate (3a) were biotransformed by the marine sediment-derived fungal strains Purpureocillium lilacinum BC17-2 and Emericellopsis maritima BC17. Fermentations led to the isolation of sixteen derivatives, which exhibited noteworthy stereoselectivities. The absolute configurations of the optically active indane and phenylpropyl derivatives isolated were determined through electronic circular dichroism and optical rotation dispersion computational calculations. Furthermore, given the known biocatalytic potential of the phytopathogenic fungus Botrytis cinerea to modify the structures of certain antifungal phenylpropyl derivatives, substrates 3 and 3a were also subjected to biotransformation by the strain B. cinerea UCA992. The antifungal activities of the biotransformation products (R)-5, (S)-6, syn-(1S,2R)-7, anti-(1R,2R)-7, (R)-8, (R)-9, threo-(1R,2R)-11, and erythro-(1R,2S)-11 were evaluated against B. cinerea UCA992 using a resazurin-based microdilution method. Full article

Unguisins, a class of structurally complex cyclic peptides featuring a γ-aminobutyric acid residue embedded in the skeleton, exhibit diverse biological activities. Here, a new unguisin K, along with three known congeners, was isolated from the marine-derived fungus Aspergillus candidus MEFC1001. The biosynthetic pathway was elucidated through gene disruption coupled with in vitro enzymatic characterization. The ugs biosynthetic gene cluster (BGC) containing ugsA and ugsB, in conjunction with an extra-clustered gene ugsC, collaborates to synthesize these unguisins. The alanine racemase (AR) UgsC catalyzes the isomerization of Ala and provides d-Ala as the starter unit for the non-ribosomal peptide synthetase (NRPS). The unique localization of ugsC outside the ugs BGC is different from previously reported unguisin-producing systems where AR genes reside within BGCs. The methyltransferase UgsB mediates a key pre-modification step by methylating phenylpyruvic acid to yield β-methylphenylpyruvate, which is subsequently incorporated as β-methylphenylalanine during NRPS assembly. This represents the first experimental evidence of the β-carbon methylation of Phe residue occurring at the precursor level rather than through post-assembly modification. The NRPS UgsA recruits a variety of amino acids for assembly and cyclization to form mature unguisins. Additionally, genome mining utilizing UgsA as a query identified homologous NRPSs in diverse fungal species, highlighting the potential for unguisin production in fungi. This study enriches the biosynthetic diversity of cyclic peptides and provides guidance for exploring unguisin-like natural products derived from fungi. Full article

In this investigation, the anti-inflammatory potential of phenylspirodrimanes (PSDs) produced by the marine-derived fungal strain Stachybotrys sp. SZU-W23 was systematically explored. A total of 15 PSDs were successfully isolated. Among them, four novel compounds, designated as chartarlactams U-X, were precisely characterized using NMR, HRESIMS, and ECD analyses. Specifically, compound 10 exhibited the most potent inhibitory effect on nitric oxide production in LPS-stimulated RAW 264.7 macrophages within the 0.3–30 μM concentration range, with an IC₅₀ value of 12.4 μM. Additionally, MTT assays revealed no detectable cytotoxicity at these concentrations. Mechanistic studies revealed that compound 10 effectively suppressed ROS generation, likely inactivating the NF-κB signaling pathway and consequently downregulating pro-inflammatory mediators, including iNOS, IL-6, and IL-1β. Full article

Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder, yet effective agents for its prevention and therapy remain highly limited. Epicoccin A, a significant secondary metabolite from Exserohilum sp., demonstrates various biological activities; however, its neuroprotective effects have not been elucidated. Here, we investigated the therapeutic potential of epicoccin A for PD by evaluating its impact on neural phenotype, reactive oxygen species (ROS) generation, and locomotor activity in PD-like zebrafish. Transcriptomic analysis and molecular docking were conducted, with key gene expressions further verified using real-time qPCR. As a result, epicoccin A notably mitigated dopaminergic neuron loss, neural vasculature deficiency, nervous system injury, ROS accumulation, locomotor impairments, and abnormal expressions of hallmark genes associated with PD and oxidative stress. Underlying mechanism investigation indicated epicoccin A may alleviate PD-like symptoms by activating PINK1/Parkin-dependent mitophagy, as evidenced by the reversal of aberrant gene expressions related to the pink1/parkin pathway and its upstream mTOR/FoxO pathway following epicoccin A co-treatments. This finding was further confirmed by the robust interactions between epicoccin A and these mitophagy regulators. Our results suggest that epicoccin A relieves PD symptoms by activating pink1/parkin-dependent mitophagy and inhibiting excessive oxidative stress, highlighting its potential as a therapeutic approach for PD. Full article

Sixteen polyketides, including six new compounds (1–2, and 5–8), were isolated from the culture of the marine sponge-associated fungus Neopestalotiopsis sp. SCSIO 41422. Their structures were elucidated through NMR, MS spectroscopic analyses, calculated electronic circular dichroism, quantum chemical NMR calculations, and X-ray single-crystal diffraction. To screen and evaluate the inhibitory activity of these polyketides in renal fibrosis, a TGF-β1-stimulated HK-2 cell model was used. All tested compounds (1, 5–8, and 11–12) at 10 µM showed obvious anti-fibrotic activity by inhibiting TGF-β1-induced α-SMA expression and extracellular matrix production (collagen I and fibronectin). Among them, gamahorin A (1) was shown to be the most potent and the most promising inhibitor against renal fibrosis. Full article

Isaridin E, a cyclodepsipeptide derived from the marine fungus Beauveria felina (SYSU-MS7908), has been demonstrated to possess multiple biological properties. In this study, we employed both lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells (HUVECs) and a LPS-induced murine endotoxemia model to investigate its anti-inflammatory effects. Our results revealed that isaridin E suppressed the expression of pro-inflammatory cytokines and adhesion molecules in a concentration dependent manner, while also reducing monocyte adhesion to endothelial cells. Furthermore, this compound attenuated vascular hyperpermeability and inflammatory cell infiltration in the lungs, as well as preserving the integrity of the aortic and pulmonary tissues. At the molecular level, isaridin E was found to downregulate TLR4 expression, increase IκBα levels, and inhibit the LPS-induced phosphorylation and nuclear translocation of NF-κB p65. In conclusion, our findings indicate that isaridin E exerts robust anti-inflammatory effects in LPS-induced endotoxemia through the suppression of the TLR4/NF-κB signaling axis, positioning it as a promising therapeutic candidate for vascular inflammatory disorders. Full article

Two new decalin-tetramic acid hybrid metabolites, zopfiellamides C (1) and D (2) were isolated from the marine-derived fungus Aspergillus sp. NF666. The structure determination was accomplished on the basis of HRESIMS and NMR spectral data analyses including COSY, HSQC, HMBC, and NOESY experiments. Both isolated metabolites (1 and 2) exhibited significant growth inhibition against four clinically relevant bacterial strains with minimum inhibitory concentration (MIC) values of about 12.5 μΜ. Moreover, we proposed a plausible biosynthetic pathway of zopfiellamide D (2) in this work. Full article

Three new eremophilane sesquiterpenoids (1–3), together with six known analogues, were isolated from the marine-derived fungus Phoma sp. DXH009. Their structures were elucidated through detailed NMR and MS spectroscopic analysis, and the absolute configurations of 1–4 were determined by conformational analysis and quantum chemical TDDFT-ECD calculation. Their anti-neuroinflammatory activities were evaluated using the lipopolysaccharide (LPS)-induced BV2 microglial cells. The results indicated that compound 5 (dihydrosporogen AO-1) exhibited significant inhibitory effects on the production of nitric oxide (NO) levels (EC₅₀ = 3.11 μM) with less cytotoxicity, leading to a reversal effect in inducing microphage polarization in LPS-treated BV2 microglial cells. These were correlated with suppressions of the canonical NF-κB pathway as well as the expression levels of key neuroinflammatory markers, including COX2, TNF-α, IL-6, and IL-1β. Correspondingly, treating 5 in LPS-induced mice efficiently ameliorated neuroinflammation in the tissues of the cortex and hippocampus. These findings suggest that eremophilane sesquiterpenoid 5 could be a potential candidate for the development of anti-neuroinflammatory drugs. 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

Filoviruses, mainly consisting of the two genera of Ebolavirus and Marburgvirus, are enveloped negative-strand RNA viruses that can infect humans to cause severe hemorrhagic fevers and outbreaks with high mortality rates. However, we still do not have effective medicines for treating these diseases. To search for effective drugs, we have identified three marine indole alkaloids that exhibit potent activities against filovirus infection. Thus, it is suggested that marine indole alkaloids can be a valuable compound source for filovirus drug screening and development. Since marine indole alkaloids comprise a large diverse group of secondary metabolites, their biological properties would be helpful for pharmaceutical drug development to treat various filovirus infections. Full article

A detailed chemical study of the culture of a coral-derived fungus Penicillium chrysogenum resulted in the isolation and identification of four new aromatic heterocycles chrysoquinazolinones A–B (1–2) and chrysobenzothiazoles A–B (3–4), along with a new sorbicillinoid 4-carboxylsorbicillin (5). Chrysoquinazolinones A–B (1–2) combine a quinazolinone fragment with a bicyclo[2.2.2]octane or a pyrrolidone moiety, respectively, demonstrating the unexpected structures of marine natural products. Chrysobenzothiazoles A–B (3–4) possess a benzothiazole system and are the second isolation of this class of skeleton compounds from marine organisms. The existence of the pair of enantiomers (±3) was deduced by chiral HPLC analysis. Their structures and absolute configurations were elucidated by detailed spectroscopic analysis, comparison with the literature data, single-crystal X-ray crystallographic analysis and TDDFT-ECD calculations. Compound 5 exhibited moderate cytotoxicity against K562 and NCI-H446 cell lines, with IC₅₀ values of 15.00 μM and 16.87 μM, respectively. Full article

Six new highly oxidized seco-terpenoids, including three 3-nor-labdane type diterpenes, talaroterpenoids A–C (1–3), and three meroterpenoids containing an orthoester group, talaroterpenoids D–F (6–8), together with five known compounds (4–5 and 9–11), were isolated from the marine-derived fungus Talaromyces aurantiacus. Their chemical structures were elucidated through 1D, 2D NMR, HRESIMS, J-based configuration analysis (JBCA), computational ECD calculations, and single-crystal X-ray diffraction analysis. Compounds 1 and 2 contain an unusual 6,20-γ-lactone-bridged scaffold. Compounds 10 and 11 presented inhibitory effects on NO release in lipopolysaccharide (LPS)-induced BV-2 cells with IC₅₀ values of 11.47 and 11.32 μM, respectively. Talaroterpenoid C (3) showed moderate antifungal activity against A. alternata and P. theae Steyaert. Full article

The first total synthesis of the Australian marine tunicate fungus-derived cyclic peptide talarolide A (1) has confirmed the structure previously proposed on the basis of spectroscopic and chemical analyses and re-affirmed the importance of the unique hydroxamate H-bond bridge in ring conformer stabilization. The unexpected co-synthesis of atrop-talarolide A (8) revealed, for the first time, that hydroxamate H-bond bridging in the talarolide framework invokes non-canonical atropisomerism and that talarolides A (1), C (3), and D (4) all exist naturally as atropisomers. These discoveries raise the intriguing prospect that comparable functionalisation of other cyclic peptides, including those with commercial value, could provide ready access to new “unnatural atropisomeric” chemical space, with new and/or improved chemical and biological properties. Full article

Two new fusarochromanone derivatives, deacetylfusarochromene (1) and deacetamidofusarochrom-2′,3-diene (2), along with the previously reported metabolites fusarochromanone TDP-2 (3), fusarochromene (4), 2,2-dimethyl-5-amino-6-(2′E-ene-4′-hydroxylbutyryl)-4-chromone (5), fusarochromanone (6), (−)-chrysogine (7), and equisetin (8), were isolated from the marine fungus Fusarium equiseti UBOCC-A-117302. The structures of the compounds were determined by extensive spectrometric (HRMS) and spectroscopic (1D and 2D NMR) analyses, as well as specific rotation. Among them, 2 and 5 showed inhibition of three protein kinases with IC₅₀ values ranging from 1.42 to 25.48 μM. Cytotoxicity and antimicrobial activity of all isolated compounds were also evaluated. Six fusarochromanone derivatives (1–6) exhibited diverse activities against three cell lines, RPE-1, HCT-116, and U2OS (IC₅₀ values ranging from 0.058 to 84.380 μM). Equisetin (8) showed bactericidal activities against Bacillus cereus and Listeria monocytogenes (MBC values of 7.8 and 31.25 µM, respectively), and bacteriostatic activity against Enterococcus faecalis (MIC value of 31.25 µM). Compounds 2 and 4 showed bacteriostatic activities against Listeria monocytogenes (MIC of 125 µM). Full article

Altechromone A, also known as 2,5-dimethyl-7-hydroxychromone, is a hydroxyketone containing one hydroxyl and one ketone group. In this study, we isolated Altechromone A from the marine-derived fungus Penicillium Chrysogenum (XY-14-0-4). Previous reports show that Altechromone A has various activities including tumor suppression, antibacterial, and antiviral activities. However, there is no study about its anti-inflammatory activity in inflammatory bowel disease (IBD). Here, we assess the anti-inflammatory activity, especially in IBD, and its potential mechanism using the zebrafish model. Our results indicated that Altechromone A has anti-inflammatory activity in a CuSO₄-, tail-cutting-, and LPS-induced inflammatory model in zebrafish, respectively. In addition, Altechromone A greatly reduced the number of neutrophils, improved intestinal motility and efflux efficiency, alleviated intestinal damage, and reduced reactive oxygen species production in the TNBS-induced IBD zebrafish model. The transcriptomics sequencing and real-time qPCR indicated that Altechromone A inhibited the expression of pro-inflammatory genes including TNF-α, NF-κB, IL-1, IL-1β, IL-6, and NLRP3. Therefore, these data indicate that Altechromone A exhibits therapeutic effects in IBD by inhibiting the inflammatory response. Full article