New Antifungal and Antifeedant Metabolites from Daldinia eschscholtzii Cocultured with Colletotrichum pseudomajus.

The synchronous co-culture of Daldinia eschscholtzii and Colletotrichum pseudomajus produced one new linear polyketide, eschscholin C (1), along with three known compounds (2-4). One new acorane sesquiterpene, coldaldrin A (5), and one new amide derivative, coldaldamide A (6) as the probe for polyketide intermediate capture, and three known compounds (7-9) were isolated from the sequential co-culture of D. eschscholtzii with C. pseudomajus. The structures and absolute configurations of 1, 5 and 6 were established by spectroscopic analysis including 1D, 2D NMR, the calculations of the NMR, and ECD data. Most compounds showed significant antifungal activities against the tea pathogens C. pseudomajus, and Fusarium asiaticum with MICs of 2-8 µg/mL. Compound 4 also showed antifeedant activity against silkworms with feeding deterrence indices of 79% at the concentration of 50 µg/cm2.

The Antiphytopathogenic Metabolites and the Synergy of Endophytes Paraphaeosphaeria sp., Nigrospora oryzae from the Same Ginkgo biloba Host.

Two endophytes from the same Ginkgo biloba host were isolated and cultured separately. Three new eremophilane sesquiterpenoids (1-3), three new furan derivates (6, 8-9), one new polyketide (10), and four known compounds (4, 5, 7, 11) from Paraphaeosphaeria sp. and two new 10-membered macrolides (12-13), a new liner polyketide (14), a new benzofuran (15), and six known compounds (16-21) from Nigrospora oryzae were isolated. The structures of the isolated compounds were determined by spectroscopic methods, NMR calculations, and ECD calculations. The compounds 3-7, 9-10, 12, and 14-17 showed significant antiphytopathogenic effects against mycotoxigenic Alternaria sp. comparable to the activity of nystatin (positive control). Compounds 2, 6, 8, 9, and 18 indicated inhibitions against phytopathogen Fusarium asiaticum with MICs < 10 µg/mL. In addition, the compounds with weak antifungal activities from two endophytes were mixed to test their antifungal activity. The results showed that the metabolites from two endophytes had synergistic antifungal effects, and the beneficial interactions between natural products can induce more antifungal effects against plant pathogens than that of single compounds.

Specialized metabolites of the endophyte Annulohypoxylon areolatum hosted by Aconitum carmichaelii.

Seven previously undescribed compounds, including one amino acid hybrid sesquiterpene areolatol A (1), two unusual natural sesquiterpenoid skeleton areolatones A-B (2-3) and four benzo[j]fluoranthene areolaranes A-D (4-7) were characterized from Annulohypoxylon areolatum. The structures of the compounds were determined by extensive spectroscopic analysis, X-ray diffraction analysis, and ECD and NMR computational. Notably, areolatol A (1) was the first reported sesquiterpene featuring a 5/7/3-ring system and hybridized with two molecular amino acids. In addition, areolaranes A-D (4-7) were identified as possible chemophenetic markers.

The new analogues of ß-trans-bergamotene from endophytic fungus Nigrospora sp. E121 with yam culture medium.

Two new bicyclic sesquiterpenes,Δ9-2, 5, 11-trihydroxyl-ß-cis-bergamotene (3) and Nigrohydroin A (4), together with ten known compounds (1, 2 and 5-12) were obtained from endophytic fungus Nigrospora sp. E121. The structures were elucidated on the basis of their 1D and 2D NMR spectra and mass spectrometric data. The possible biosynthetic pathway of compounds 1, 2, 3 and 4 in Nigrospora sp. E121were reported according to literature. The phytotoxic assay results indicated that the acetyl fragment in α-acetylorcinol may contribute to the phytotoxic activity of this compound.

Accumulation of antitumor polyketides by fermentation of Rubus delavayi Franch. with Clonostachys rogersoniana.

The aim of this work is to explore the effects of herbal medicine on secondary metabolites of microorganisms during fermentation. Clonostachys rogersoniana was found to metabolize only small amounts of polyketide glycosides rogerson B and C on fresh potatoes, but after replacing the medium to the medicinal plant Rubus delavayi Franch., the type and content of the metabolized polyketones showed significant changes. The sugars and glycosides in R. delavayi are probably responsible for the changes in secondary metabolites. Six polyketide glycosides including a new metabolite, rogerson F, and two potential antitumor compounds, TMC-151C and TMC-151D, were isolated from the extract of R. delavayi fermented by C. rogersoniana. In addition, 13C labeling experiments were used to trace the biosynthesis process of these compounds. TMC-151C and TMC-151D showed significant cytotoxic activity against PANC-1, K562 and HCT116 cancer cells but had no obvious cytotoxic activity against BEAS-2B human normal lung epithelial cells. The yields of TMC-151C and TMC-151D reached 14.37 ± 1.52 g/kg and 1.98 ± 0.43 g/kg, respectively, after fermentation at 28 °C for 30 days. This is the first study to confirm that herbal medicine can induce microbes to metabolize active compounds. And the technology of fermenting medicinal materials can bring more economic value to medicinal plants.

The antifungal metabolites from coculture of Aspergillus fumigatus and Alternaria alternata associated with Coffea arabica.

One new cyclohexenone derivative, asperfumtone A (1) along with six known compounds were obtained from the coculture of Aspergillus fumigatus and Alternaria alternata associated with Coffea arabica. The configuration of 2 was first reported in the research. The structures were determined by extensive spectroscopic analyses, and ECD calculation. Compounds 3, 4 and 7 showed significant antifungal activities against coffee phytopathogens A. alternata and Fusarium incarnatum with MICs of 1 µg/mL. Compounds 1 and 2 showed weak antifungal activities against A. alternata and F. incarnatum with MICs of 32-64 µg/mL.

Antifeedant, Antifungal Cryptic Polyketides with Six Structural Frameworks from Tea Endophyte Daldinia eschscholtzii Propelled by the Antagonistic Coculture with Phytopathogen Colletotrichum pseudomajus and Different Culture Methods.

The antagonistic coculture with tea phytopathogen Colletotrichum pseudomajus induces antifungal cryptic metabolites from isogenesis endophyte Daldinia eschscholtzii against tea phytopathogens. Sixteen new polyketides with six structural frameworks including ten cryptic ones, named coldaldols A-C (1-3), collediol (5), and daldinrins A-L (10-20 and 23), were found from the coculture of C. pseudomajus and D. eschscholtzii by different culture methods. The unique framework of compounds 11 and 12 featured a benzopyran-C7 polyketone hybrid, and compounds 13-16 were characterized by the novel benzopyran dimer. The structures were determined mainly by spectroscopic methods, including extensive one-dimensional (1D), two-dimensional (2D) NMR, high resolution electrospray ionisation mass spectroscopy (HRESIMS), ECD calculation, and single-crystal X-ray diffraction. The configuration of acyclic compounds 5 and 18 were determined by application of the universal NMR database. Most compounds showed significant antifungal activities against the tea pathogens C. pseudomajus and Alternaria sp. with MICs of 1-8 µg/mL. Compound 12 had stronger antifungal activity than that of positive drug nystatin. The ether bond at C-4 of the benzopyran derivative increased the antifungal activity. Compounds 4-9 and 11-23 showed antifeedant activities against silkworms with feeding deterrence indices of 15-100% at the concentration of 50 µg/cm2.

Genome mining of actinomycin shunt products from Kitasatospora sp. YINM00002.

Actinomycins are known for their anti-tumor, antibacterial and antiviral activities, and in particular for the ability of actinomycin D as a clinical drug to treat a variety of cancers. In our ongoing work to obtain novel natural products from endophytic actinomycetes derived from traditional Chinese herbs, we identified the potential to produce actinomycins in YINM00002, a Kitasatospora strain derived from Polygonatum kingianum. According to genome mining, we isolated actinomycins D and V (1 and 2) and small amounts of 4-methyl-3-hydroxyanthranilic acid (4-MHA) derivates (3 and 4) from strain fermentation broth. The presence of actinrhater A (3) and actinrhater B (4) reveals a mysterious shunt pathway in the early stages of actinomycin D biosynthesis. Our study provides a fresh perspective for further discovery and modification of novel actinomycins.

The antifungal metabolites isolated from maize endophytic fungus Fusarium sp. induced by OSMAC strategy.

Six new sesquiterpenes, fusarchlamols A-F (1, 2, 4-7); one new natural product of sesquiterpenoid, methyltricinonoate (3); and ten known compounds were found from Fusarium sp. cultured in two different media by the one strain many compounds strategy. The compounds (1, 2, and 4-11) were isolated from Fusarium sp. in PDB medium, and compounds (3-5, 8, and 10-17) were discovered from Fusarium sp. in coffee medium. Additionally, the configuration of 8 was first reported in the research by Mosher's method. The structures were established by 1D, 2D NMR, mass spectrometry, calculated ECD spectra, and Mosher's method. Compounds 1, 2, 6/7, 12, and 16 indicated significant antifungal activities against the phytopathogen Alternaria alternata isolated from Coffea arabica with MICs of 1 µg/mL. The investigation on the anti-phytopathogen activity of metabolites can provide lead compounds for agrochemicals.

Guided isolation of secondary metabolites from Nectria sp. MHHJ-3 by molecular network strategy.

The fungus Nectria sp. MHHJ-3 was isolated from Illigera rhodantha. A molecular networking-guided the secondary metabolites investigation of Nectria sp. MHHJ-3 led to the isolation of ten metabolites (1-10), including two new naphthalenone derivatives, nectrianaphthalenones A (1) and B (2), and two new steroids, nectriasteroids A (3) and B (4). Their structures were elucidated by extensive spectroscopic analysis including the HRESIMS, 1D/2D NMR and electronic circular dichroism (ECD) spectra. A plausible biosynthetic pathway for 1-2 was proposed. Compounds 1 and 2 exhibited moderate acetylcholinesterase (AChE) inhibitory activities. Compounds 3 and 4 showed significant cytotoxic activity against selected tumor cells. Particularly, compound 3 exhibited the strongest activity against A549 cells with an IC50 value of 13.73 ± 0.03 µM, which was at the same grade with that of positive control cisplatin.

Discovery of pyranonaphthoquinones and an eighteen-membered ring macrolide from the rhizospheric soil-derived fungus Phialocephala sp. YUD18001 by OSMAC strategy.

Two new pyranonaphthoquinones, phialoyxinones A (1) and B (2), a new eighteen-membered ring lactone, phialoyxtone (3), and five known pyranonaphthoquinone derivatives were identified from the fungus Phialocephala sp. YUD18001, which was isolated from the rhizospheric soil associated with Gastrodia elata. Their structures were unequivocally established by a comprehensive interpretation of the spectroscopic data, with the stereochemistry for 1-3 was defined by a combination of TDDFT calculations, and the DP4+ probability analysis based on NMR chemical shift calculations. All of the new compounds 1-3 were evaluated for cytotoxicity and acetylcholinesterase inhibitory, compound 2 exhibited in vitro cytotoxic activities against five human cancer cell lines (HL-60, SMMC-7721, A549, MCF-7 and SW480) with IC50 values ranging from 11.80 to 19.32 µM. Compounds 2 and 3 exhibited moderate AChE inhibitory activities. A putative biosynthetic pathway for the pyranonaphthoquinones was proposed.

Two Decarestrictine Analogs from the Soil-Derived Fungus Penicillium sp. YUD18003 Associated with Gastrodia elata.

Two new decarestrictine analogs decarestrictine P and penicitone, together with eight known homologous compounds were isolated from the soil fungus from the rhizosphere of Penicillium sp. YUD18003 related to Gastrodia elata. Their different structures include a decanolides decartestridine P and a long-chain polyhydroxyketone penicitone. The structures of new compounds were determined by nuclear magnetic resonance (NMR) spectroscopic analysis and high resolution electrospray ionization mass spectrometry (HR-ESI-MS), while their absolute configurations were determined by spectroscopic methods, DP4+ probability analysis, modified Snatzke's method and electron circular dichroism (ECD) calculations. All compounds were evaluated for antimicrobial activities.

Proliferation Inhibitory Activity of Quinones from Blaps rynchopetera Defense Secretion on Colorectal Tumor Cells.

OBJECTIVE: To explore the proliferation inhibitory effect of quinones from Blaps rynchopetera defense secretion on colorectal tumor cell lines. METHODS: Human colorectal cancer cell HT-29, human colorectal adenocarcinoma cell Caco-2 and normal human colon epithelial cell CCD841 were chosen for the evaluation of inhibitory activity of the main quinones of B. rynchopetera defense secretion, including methyl p-benzoquinone (MBQ), ethyl p-benzoquinone (EBQ), and methyl hydroquinone (MHQ), through methyl thiazolyl tetrazolium assay. The tumor-related factors, cell cycles, related gene expressions and protein levels were detected by enzyme-linked immunosorbent assy, flow cytometry, RT-polymerase chain reaction and Western blot, respectively. RESULTS: MBQ, EBQ, and MHQ could significantly inhibit the proliferation of Caco-2, with half maximal inhibitory concentration (IC50) values of 7.04 ± 0.88, 10.92 ± 0.32, 9.35 ± 0.83, HT-29, with IC50 values of 14.90 ± 2.71, 20.50 ± 6.37, 13.90 ± 1.30, and CCD841, with IC50 values of 11.40 ± 0.68, 7.02 ± 0.44 and 7.83 ± 0.05 µg/mL, respectively. Tested quinones can reduce the expression of tumor-related factors tumor necrosis factor α, interleukin (IL)-10, and IL-6 in HT-29 cells, selectively promote apoptosis, and regulate the cell cycle which can reduce the proportion of cells in the G1 phase and increase the proportion of the S phase. Meanwhile, tested quinones could up-regulate mRNA and protein expression of GSK-3ß and APC, while down-regulate that of ß-catenin, Frizzled1, c-Myc, and CyclinD1 in the Wnt/ß-catenin pathway of HT-29 cells. CONCLUSION: Quinones from B. rynchopetera defense secretion could inhibit the proliferation of colorectal tumor cells and reduce the expression of related factors, which would be functioned by regulating cell cycle, selectively promoting apoptosis, and affecting Wnt/ß-catenin pathway-related mRNA and protein expressions.

Novel Antifungal and Antifeedant Metabolites from Penicillium chrysogenum Co-Cultured with Nemania primolutea and Aspergillus fumigatus.

The endophyte Nemania primolutea, inhibited the growth of Penicillium chrysogenum in the coculture system. Four new compounds, nemmolutines A-B (1-2), and penigenumin (3) from N. primolutea, penemin (4) from P. chrysogenum were isolated from the coculture. On the other hand, P. chrysogenum inhibited the Aspergillus fumigatus in the coculture. Induced metabolites (13-16) with monasone naphthoquinone scaffolds including a new one from P. chrysogenum were produced by the coculture of P. chrysogenum, and A. fumigatus. Interesting, cryptic metabolites penicichrins A-B isolated from wild P. chrysogenum induced by host Ziziphus jujuba medium were also found in induced P. chrysogenum cultured in PDB ordinary medium. So the induction of penicichrin production by supplementing with host extract occurred in the fungus P. chrysogenum not the host medium. The productions of penicichrins were the spontaneous metabolism, and the metabolites (13-16) were the culture driven. Compounds 4, 6, 8, 10, 11, 14, and 15 showed significant antifungal activities against the phytopathogen Alternaria alternata with MICS of 1-8 µg/mL, and compounds 7, 9, and 12 indicated significant antifeedant activities against silkworms with feeding deterrence indexes (FDIs) of 92 %, 66 %, and 64 %. The carboxy group in 4-(2-hydroxybutynoxy)benzoic acid derivatives, and xylabisboeins; the hydroxy group in mellein derivatives; and the quinoid in monasone naphthoquinone increased the antifungal activities.

Antifungal and antifeedant terpenoids from Paraphaeosphaeria sp. cultured by extract of host Ginkgo biloba.

Five undescribed terpenoids including a polyketide-terpenoid hybrid paraphaone, and four eremophilane sesquiterpenoids, paraphaterpenes A-D, as well as two known compounds were isolated from the endophytic fungus Paraphaeosphaeria sp. cultured by extract of host Ginkgo biloba L. The structures were established by spectroscopic analyses, and the single-crystal X-ray diffraction. The antifungal activity of Paraphaeosphaeria sp. cultured by extract of G. biloba against the plant pathogen Alternaria alternata was significant and higher than that of PDB medium. Tested compounds indicated antifeedant activities against silkworms with feeding deterrence index at 10-70%. Paraphaone, paraphaterpenes A, C, D and alternariol methyl ether showed significant antifungal activities against the phytopathogens A. alternata, Aspergillus fumigatus, and entomopathogen Beauveria bassiana with MICs ≤4 µg/mL. And the preliminary structure-activity relationship of eremophilane sesquiterpenoids was exhibited. The culture of Paraphaeosphaeria sp. by host G. biloba medium afforded agricultural antibiotics.

Antibiotic Guanacastane Diterpenoids with Two New Skeletons from Psathyrella candolleana Uncovered by Semisolid and Liquid Media.

The culture of Psathyrella candolleana in host Dioscorea opposite medium produced seven new guanacastane diterpenoids, psayamin (1) as an unprecedented 5/7/6/6/6/6/7/5-fused octacyclic spiro scaffold both under liquid and semisolid conditions, psathins A-C (4-6) with a 5/7/6 tricyclic backbone by liquid medium, psathins D-E (7-8) as the same unprecedented skeletons of 5/6/7/6-fused tetracyclic or 6/7/6 tricyclic structures, and psathin F (9) with a 5/7/5/6 tetracyclic backbone by semisolid medium. The structures were elucidated by detailed spectroscopic analyses and those of 1 and 7 were determined by single-crystal X-ray crystallography. The semisolid culture led to four structure types of the guanacastane diterpenoid. Compound 5 showed antifungal activity against phytopathogen Fusarium incarnatum with a minimum inhibitory concentration (MIC) of 8 µg/mL, while compound 4 showed significant antifungal activity against Alternaria sp. with an MIC of 2 µg/mL. Compounds 1 and 8 also showed antifeedant activities against the silkworms with the feeding deterrence indices of 50%, at the concentrations of 50 µg/cm2. Compound 1 showed significant cytotoxicity with IC50 at 10.87 ± 0.24-15.96 ± 0.30 µM and anti-acetylcholinesterase activity with IC50 at 37.3 µM. Also, compound 1 remarkably induced apoptosis of HL-60 at 10, 20 µM in a concentration-dependent manner. The spiral ring of 1 was vital in cytotoxicity and anti-acetylcholinesterase activity. The different media fermented by P. candolleana resulted in the chemical diversity of bioactive guanacastane diterpenoids and potential applications in the agricultural and food functions.

A new sesquiterpenoid from the aconitum-derived fungus Aspergillus fumigatus M1.

A new bergamotane sesquiterpenoid, fumigatanol (1), along with nine known compounds (2-10) were isolated from the Aconitum-derived fungus Aspergillus fumigatus M1. Their structures were established on the basis of extensive spectroscopic analyses, ECD experiment and NMR computational method. Antibacterial and cytotoxic activities of compound 1 were evaluated and no obvious antibacterial and cytotoxic activities were observed at concentrations of 256 µg/mL and 40.00 µM, respectively.

A new cycloheptane derivative from the fungus Penicillium crustosum JT-8.

A new highly oxygenated cycloheptane derivative crustane (1), along with fourteen known compounds (2-15) were isolated from Penicillium crustosum JT-8. The structure of compound 1 was determined by extensive spectroscopic data, DP4+ probability analyses and dimolybdenum CD method. Compound 1 exhibited moderate antibacterial activity against Staphylococcus aureus with MIC of 4.0 µg/mL.

A new butenolide with antifungal activity from solid co-cultivation of Irpex lacteus and Nigrospora oryzae.

A new antifungal butenolide irperide (1) along with five known compounds were isolated from the co-culture of endophyte Irpex lacteus and pathogenic Nigrospora oryzae. The structure of 1, including the absolute configuration, was elucidated by analysis of NMR, HR-ESI-MS data and ECD spectra. Compounds 1, 4 and 6 exhibited significant antifungal activity against Aspergillus fumigatus, with MIC values of 1, 2 and 1 µg/mL, respectively.

Phytotoxic meroterpenoids with herbicidal activities from the phytopathogenic fungus Pseudopestalotiopsis theae.

The fungus Pseudopestalotiopsis theae isolated from the fresh leaves of Illigera celebica, has been reported to be a pathogenic fungus that can cause gray blight on tea leaves, a disease characterized by the appearance of necrotic lesions on tea leaves. The pathogenic substances in this fungus have not been clearly identified. Considering the possible involvement of specialized metabolites in symptom appearance, a chemical investigation of specialized metabolites on P. theae was conducted, resulting in the isolation of eight meroterpenoids, including six undescribed biscognienynes G-L and two known ones (biscognienynes B and D). The structures of these new compounds were characterized by extensive NMR spectroscopic and HR-ESI-MS data, and their absolute configurations were elucidated by ECD calculations. Except for biscogniyne L, all the isolated biscognienynes showed different degrees of phytotoxicity to tea in vivo, thereby revealing for the first time the substances in P. theae that cause tea gray blight. Inspired by the fact that phytotoxins produced by pathogenic fungus are an effective resource for designing natural and safe bioherbicides, when assayed the herbicidal activity through Petri dish bioassays, biscognienynes G-J showed phytotoxic effects against seed germination and seedling growth of Setaria viridis, strongly inhibiting seed germination percentage and radicle and germ lengths of seedlings. The results of this study demonstrated the great potential of biscognienynes G-J to be proposed and developed as ecofriendly herbicides.