RESUMO
Genome sequencing on an intertidal zone-derived Aspergillus flavipes strain revealed its great potential to produce secondary metabolites. To activate the cryptic compounds of A. flavipes, the global regulator flLaeA was knocked out, leading to substantial up-regulation of the expression of two NRPS-like biosynthetic gene clusters in the ΔflLaeA mutant. With a scaled-up fermentation of the ΔflLaeA strain, five compounds, including two previously undescribed piperazine derivatives flavipamides A and B (1 and 2), along with three known compounds (3-5), were obtained by LC-MS guided isolation. The new compounds were elucidated by spectroscopic analysis and electronic circular dichroism (ECD) calculations, and the biosynthetic pathway was proposed on the bias of bioinformatic analysis and 13C isotope labeling evidence. This is the first report to access cryptic fungi secondary metabolites by inactivating global regulator LaeA and may provide a new approach to discovering new secondary metabolites by such genetic manipulation.
Assuntos
Aspergillus , Fungos , Aspergillus/genética , Aspergillus/metabolismo , Piperazinas/farmacologia , Piperazinas/metabolismoRESUMO
Nine new oligophenalenone dimers, adpressins A-G (1-9), together with nine known compounds (10-18), were isolated from the fungus Talaromyces adpressus. Their chemical structures were determined on the basis of spectroscopic and mass spectral analyses. Their relative and absolute configurations were identified by 1H and 13C NMR calculations followed by DP4+ analyses, electronic circular dichroism (ECD) calculations, and ECD spectra comparison with related compounds. Compound 1 is the first example of a duclauxin derivative featuring an unusual 6/6/6/5/6/6/6 ring system, while compounds 6 and 7 contained a novel pyrrolidine ring. Compounds 5, 9, and 18 exhibited moderate inhibition against LPS-induced B lymphocyte proliferation with IC50 values ranging from 1.6 to 8.6 µM. Additionally, compounds 9 and 18 exhibited moderate inhibition against Con A-induced T lymphocyte proliferation with IC50 values of 9.3 and 2.6 µM, respectively.
RESUMO
In this study, we isolated lovastatin derivatives, including aculeatiols A-G (1-7) and three known compounds (8-10), from Aspergillus aculeatus. Their structures and absolute configurations were experimentally determined by high-resolution electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and X-ray diffraction analyses, and the results were corroborated by quantum-chemical calculations. As members of the lovastatin derivatives, aculeatiols A-C (1-3) possess a γ-lactone functional group in the side chain. Compound 6 represents the first example that features an undescribed aromatized heterotetracyclic 6/6/6/6 ring system. Biologically, the lipid-lowering effects of all of these compounds were evaluated by analyzing the free fatty acid-induced intracellular lipid accumulation. In addition, compound 5, which regulated the transcription of genes associated with lipid uptake and synthesis, inhibited the accumulation of lipids.
Assuntos
Aspergillus , Lovastatina , Aspergillus/química , Lovastatina/farmacologia , Lovastatina/química , Estrutura Molecular , HumanosRESUMO
Ten new compounds, including three pairs of diarylcyclopentenone enantiomers (±) talaromycesins A-C (1-3) and four biphenyl derivatives talaromycesins D-G (4-7), along with four known compounds (8-11), were isolated from the fungus Talaromyces adpressus. Their structures were determined by analyses of extensive NMR spectroscopic and HRESIMS data, and their absolute configurations were elucidated by the dimolybdenum tetraacetate [Mo2(AcO)4]-induced ECD spectra, X-ray crystallographic studies, and ECD calculations. These new compounds were evaluated for their immunosuppressive activities for the first time, and compound 7 probably exerted liver-protective and anti-inflammatory effects on Con A-induced AIH by decreasing the levels of inflammatory cytokines, modulating immune homeostasis, and decreasing hepatocyte apoptosis, which may become a potential drug for the treatment of autoimmune diseases.
Assuntos
Talaromyces , Espectroscopia de Ressonância Magnética , Talaromyces/química , Compostos de Bifenilo , Estrutura MolecularRESUMO
A novel and convenient K2S2O8-mediated diiodo cyclization of 1,6-enynes for the facile synthesis of functionalized γ-lactam derivatives has been developed. This reaction features mild and transition-metal-free conditions, which offer a green and efficient entry to synthetically important γ-lactam scaffolds. Mechanistic studies suggest that iodide radicals initiate the cascade cyclic transformation.
RESUMO
Fumitryprostatin A (1), the first example of an indole diketopiperazine alkaloid with a tricyclic 5/6/5 skeleton characterized by a dipyrrolo[1,2-a:1',2'-d]pyrazine-5,10-dione ring system decorated with a prenylated indole moiety, and fuminoid A (2), a sesquiterpenoid with a bicyclo[3.2.1]octane ring featuring a novel carbon skeleton via the transformation of the methyl, were isolated from the fungus Aspergillus fumigatus along with six known diketopiperazine alkaloids. The structure with the absolute configuration of 1 was determined based on spectroscopic analyses and X-ray crystallographic analysis, while the configuration of 2 was assigned tentatively by 13C NMR data with DP4+ probability analyses and ECD calculations. A plausible biosynthetic pathway for 1 was proposed starting from L-Trp and L-Pro via normal indole diketopiperazine. Compound 1 exhibited moderate cytotoxic activity with an IC50 value of 14.6 µM, while compound 8 exhibited moderate immunosuppressive activity in vitro.
Assuntos
Alcaloides , Sesquiterpenos , Aspergillus fumigatus , Sesquiterpenos Monocíclicos , Dicetopiperazinas/farmacologia , Dicetopiperazinas/química , Alcaloides Indólicos/farmacologia , Alcaloides Indólicos/química , Alcaloides/farmacologia , Alcaloides/química , Espectroscopia de Ressonância Magnética , Sesquiterpenos/farmacologiaRESUMO
Twelve new fungal polyketides, koningiopisins I-P (1-8) and trichoketides C-F (9-12), together with six known congeners (13-18), were isolated from Trichoderma koningiopsis, a rhizosphere fungus obtained from the medicinal plant Polygonum paleaceum. Their structures and absolute configurations were established by spectroscopic analysis, single-crystal X-ray diffraction, the modified Mosher's method, chemical derivatization, the octant rule, and 13C NMR and ECD calculations. Compounds 1-5 are tricyclic polyketides possessing an octahydrochromene framework with a 6,8-dioxabicyclo[3.2.1]octane core. Compounds 7 and 8 contain a unique ketone carbonyl group at C-7 and differ from other members of this group of compounds with the ketone carbonyl group at C-1. Compounds 1, 2, and 13 showed inhibitory activity on LPS-induced BV-2 cells on NO production with IC50 values of 14 ± 1, 3.0 ± 0.5, and 8.9 ± 2.7 µM, respectively.
Assuntos
Plantas Medicinais , Polygonum , Policetídeos , Policetídeos/química , Rizosfera , Estrutura Molecular , Espectroscopia de Ressonância Magnética , FungosRESUMO
Nine new ergosteroids (1-9) and seven known ones (10-16) were isolated from Talaromyces adpressus. Their structures and absolute configurations were determined by the interpretation of NMR spectroscopic data, HRESIMS, ECD calculations, and single-crystal X-ray diffraction analyses. Structurally, compound 1 was an ergosteroid with two epoxy and a 3α-OH group at ring A, while compounds 8 and 9 had a contracted ring A with a peroxy bridge between C-3 and C-9, which were reported for the first time. Compounds 2-6, 9, 11, and 15 displayed cytotoxic activities with IC50 values ranging from 0.4 to 32 µM, and compound 7 exhibited an immunosuppressive effect against LPS-induced B lymphocyte proliferation with an IC50 value of 8.6 µM. The structure-activity relationships of these compounds are briefly discussed.
Assuntos
Antineoplásicos , Talaromyces , Proliferação de Células , Cristalografia por Raios XRESUMO
Lasiodiplodiapyrones A and B (1 and 2), two new preussomerin derivatives, possessing an unexpected 6-methyl-4H-furo[3,2-c]pyran-4-one moiety and a highly functionalized conjoint and complicated polycyclic ring system, along with two known congeners (3 and 4), were isolated from the fungus Lasiodiplodia pseudotheobromae. Their structures including absolute configurations were determined by spectroscopic analyses, Mosher's method, and ECD calculations. A biosynthetic pathway was proposed to explain the origin of lasiodiplodiapyrones A and B as well as their relationship with preussomerins. Compounds 1-4 showed suppressive effects on the production of NO with IC50 values of 4.8 ± 0.3, 8.5 ± 1.1, 5.9 ± 0.8, and 12.8 ± 1.3 µM, respectively.
Assuntos
Ascomicetos , Pironas , Estrutura Molecular , Ascomicetos/química , PiranosRESUMO
Spectasterols A-E (1-5), aromatic ergosterols with unique ring systems, were isolated from Aspergillus spectabilis. Compounds 1 and 2 possess a 6/6/6/5/5 ring system with an additional cyclopentene, while 3 and 4 have an uncommon 6/6/6/6 ring system generated by the D-ring expansion via 1,2-alkyl shifts. Compound 3 exhibited cytotoxic activity (IC50 6.9 µM) and induced cell cycle arrest and apoptosis in HL60 cells. Compound 3 was anti-inflammatory; it decreased COX-2 levels at the transcription and protein levels and inhibited the nuclear translocation of NF-κB p65.
Assuntos
Aspergillus , NF-kappa B , Humanos , NF-kappa B/metabolismo , Aspergillus/metabolismo , Anti-Inflamatórios/farmacologia , Apoptose , Ergosterol/farmacologiaRESUMO
Six griseofulvin analogues named penigriseofulvins A - F (1-6), including three undescribed compounds and three undescribed natural products, were isolated from the fungus Penicillium griseofulvum. Their structures and absolute configurations were determined by NMR spectroscopic analyses, HRESIMS, and X-ray diffraction experiments. All compounds were evaluated for their anti-inflammatory activity, of which compounds 1 and 4 showed potential anti-inflammatory effects in RAW264.7 macrophages and ulcerative colitis mice.
Assuntos
Griseofulvina , Penicillium , Camundongos , Animais , Griseofulvina/farmacologia , Anti-Inflamatórios/farmacologia , Penicillium/química , Espectroscopia de Ressonância Magnética , Estrutura MolecularRESUMO
Five new cyclopiazonic acid related indole alkaloids, pegriseofamines A-E (1-5), were isolated from the fungus Penicillium griseofulvum. Their structures and absolute configurations were determined by NMR, HRESIMS, quantum-chemical calculation, and X-ray diffraction experiments. Among them, pegriseofamine A (1) possesses an undescribed 6/5/6/7 tetracyclic ring system generated by the fusion of an azepine and an indole unit via a cyclohexane, and the postulated biosynthetic origin of 1 was discussed. Compound 4 could relieve liver injury and prevent hepatocyte apoptosis in ConA-induced autoimmune liver disease.
Assuntos
Alcaloides Indólicos , Penicillium , Alcaloides Indólicos/química , Penicillium/química , Fungos , Estrutura MolecularRESUMO
Two pairs of new bisabolane-type sesquiterpenoids, (+)-aspersydowin A (7S) [(+)-1], (-)-aspersydowin A (7R) [(-)-1], (+)-aspersydowin B (7S,11S) [(+)-2], (-)-aspersydowin B (7R,11R) [(-)-2], along with six known compounds (1-8) were isolated from the fungus Aspergillus sydowii. Compounds 1 and 2 are enantiomers resolved by the Chiralpak IC, using a hexane- propan-2-ol mobile phase. The structure of 1 and 2 with absolute configuration were assigned tentatively by 1D (1 H, 13 C, and DEPT) & 2D (HSQC, 1 H-1 H COSY, HMBC, and NOESY) NMR data analyses and ECD calculations. Compounds 1-8 were screened for the biological activities inâ vitro. The results showed that compounds 3, 4 and 8 exhibited immunosuppressive activities with IC50 values of 10.9, 17.6 and 13.4â µM, respectively.
Assuntos
Aspergillus , Sesquiterpenos , Sesquiterpenos Monocíclicos , Estrutura Molecular , Aspergillus/química , Sesquiterpenos/químicaRESUMO
Talaromynoids A-E (1-5), five new fusicoccane diterpenoids, were obtained from the endophytic fungus Talaromyces sp. DC-26, which was isolated from a wild leech. Talaromynoid A (1) represents the first fusicoccane diterpenoid bearing an unexpected 5-7-5 tricyclic ring system, which is possibly derived from normal 5-8-5 ones by ring contraction. Talaromynoid E (5) is characterized by an unusual oxygen bridge between C-1 and C-8 that establishes the eight-membered ring B to be a 9-oxo-bicyclo[3.3.1]nonane. Structures of 1-5 with absolute configurations were determined by extensive NMR spectral analyses, electronic circular dichroism (ECD) calculations, X-ray diffraction analyses, and acid hydrolysis.
Assuntos
Diterpenos , Talaromyces , Dicroísmo Circular , Cristalografia por Raios X , Diterpenos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Talaromyces/químicaRESUMO
The thermal tetradehydro-Diels-Alder (TDDA) reaction for the synthesis of polysubstituted aromatic compounds remains underestimated probably due to the harsh conditions and multiproduct results. Herein, a mild intramolecular TDDA reaction of aryldiyne compounds is presented with linear naphthalenes only, exhibiting good functional group tolerance. The reaction is easy to operate and amenable to multigram-scale synthesis. From the preliminary work, it was found that the mild conditions may be the key to the completely linear product in the reactions.
Assuntos
Naftalenos , Reação de CicloadiçãoRESUMO
Talasterone A (1), an unprecedented 6/6/5 tricyclic 13(14 â 8)abeo-8,14-seco-ergostane steroid, together with two known congeners dankasterone B (2) and (14ß,22E)-9,14-dihydroxyergosta-4,7,22-triene-3,6-dione (3), were characterized from Talaromyces adpressus. The structure of 1 with absolute configuration was elucidated based on NMR spectroscopic data and ECD calculation. Compound 2 belongs to a class of unconventional 13(14 â 8)abeo-ergostanes, which have been renewed via the 1,2-migration of C-13-C-14 bond to C-8. In addition, compound 1 represents the first example of ergostane with a tricyclic 13(14 â 8)abeo-8,14-seco-ergostane skeleton. The proposed biosynthetic pathway was established with the support of the coisolation of the known congeners from the producing organism. It is especially noteworthy that compound 1 exhibited potent anti-inflammatory activity with an IC50 value of 8.73 ± 0.66 µM, inhibiting the NF-κB pathway and thus reducing the production of proinflammatory cytokines.
Assuntos
Ergosterol , Talaromyces , Ergosterol/análogos & derivados , Ergosterol/farmacologia , Estrutura Molecular , Esqueleto , Talaromyces/químicaRESUMO
Hyperformitins A-I (1-9), nine undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) with double-bond migration, along with four new isomers hyperformitins J-M (10-13), were isolated from Hypericum perforatum. Their structures and absolute configurations were determined by spectroscopic analyses including HRESIMS, IR, UV, NMR, and ECD, as well as optical rotation (OR) calculations. The absolute configurations of previously reported analogues, garsubellins D and C as well as garcinielliptones L and M, were assigned for the first time by NMR spectra and specific rotations analyses assisting with OR calculations. Selected compounds were tested for their immunosuppressive activities against lipopolysaccharide (LPS)-induced B lymphocyte proliferation. Compounds 1, 3, 4, 5, 7, and 11 showed inhibition activities against the proliferation of B lymphocyte with IC50 values ranging from 4.1 to 9.7 µM. Furthermore, the neuroprotective activities of the isolates against corticosterone (CORT)-induced injury in PC12 cells were also tested, and compounds 1, 12, and 13 exhibited neuroprotective effects with cell viabilities of 68.0%, 71.3%, and 68.4%, respectively under the concentration of 10 µM.
Assuntos
Antineoplásicos/farmacologia , Hypericum/química , Imunossupressores/farmacologia , Fármacos Neuroprotetores/farmacologia , Floroglucinol/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Linfócitos B/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imunossupressores/química , Imunossupressores/isolamento & purificação , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/farmacologia , Estrutura Molecular , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/isolamento & purificação , Células PC12 , Floroglucinol/química , Floroglucinol/isolamento & purificação , Ratos , Relação Estrutura-AtividadeRESUMO
Eleven undescribed quinolone alkaloids, pesimquinolones I-S (1-4 and 6-12), as well as eleven known congeners (5 and 13-22), were isolated from the solid culture broth of the fungus Penicillium simplicissimum. Their chemical structures with absolute configurations were established by a combination of NMR spectroscopy, single-crystal X-ray crystallography, and modified Mosher's methods. Pesimquinolones I-K (1-3) represent the first examples of natural occurring quinolone alkaloids that possess a 6/6/6/6 tetracyclic ring system. The anti-inflammatory activities of selected compounds on LPS-induced nitric oxide (NO) production in adherent cells were evaluated. Compounds 1 and 2 showed suppressive effects on the production of NO, with IC50 values of 10.13 and 8.10 µM, respectively.
Assuntos
Alcaloides/farmacologia , Anti-Inflamatórios/farmacologia , Óxido Nítrico/antagonistas & inibidores , Penicillium/química , Quinolonas/farmacologia , Alcaloides/química , Alcaloides/isolamento & purificação , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Lipopolissacarídeos/antagonistas & inibidores , Lipopolissacarídeos/farmacologia , Camundongos , Modelos Moleculares , Estrutura Molecular , Óxido Nítrico/biossíntese , Quinolonas/química , Quinolonas/isolamento & purificação , Células RAW 264.7 , Relação Estrutura-AtividadeRESUMO
One new spirocyclic lactone, terreinlactone C (1), and one new benzopyran derivative, 2,2-dimethyl-3-hydroxychroman-6-aldehyde (2), were discovered from the fungus Aspergillus terreus. The chemical structures of compounds 1 and 2 were elucidated by detailedly analyzing NMR and HRESIMS data. Compound 1 is the first natural product with a 1-oxaspiro[4.5]decan-2-one ring system and a possible biogenetic pathway is proposed. Two compounds were tested for their cytotoxic activities against five human cancer cell lines.[Formula: see text].
Assuntos
Benzopiranos , Lactonas , Aspergillus , Benzopiranos/farmacologia , Lactonas/farmacologia , Estrutura MolecularRESUMO
Four unusual polyketides possessing three unambiguous chemical architectures were discovered from the fermentation of Penicillium canescens assisted by the one strain-many compounds (OSMAC) strategy and MS2-based molecular networking. Penicanone (1) is the first naturally occurring polyketide characterized by a 6/6/8 tricyclic carbon skeleton incorporating an unusual bicyclo[5.3.1]hendecane core. Penicanesones A-C (2-4) are aromatic polyketide dimers simultaneously featuring inconsistent 6/5/5/6 and 6/6/5/6 heterotetracyclic ring cores. Their plausible biosynthetic pathways and screening of biological activity were described here.