RESUMO
Three new helvolic acid derivatives (named sarocladilactone A (1), sarocladilactone B (2) and sarocladic acid A (3a)), together with five known compounds (6,16-diacetoxy-25-hy- droxy-3,7-dioxy-29-nordammara-1,17(20)-dien-21-oic acid (3b), helvolic acid (4), helvolinic acid (5), 6-desacetoxy-helvolic acid (6) and 1,2-dihydrohelvolic acid (7)), were isolated from the endophytic fungus DX-THL3, obtained from the leaf of Dongxiang wild rice (Oryza rufipogon Griff.). The structures of the new compounds were elucidated via HR-MS, extensive 1D and 2D NMR analysis and comparison with reported data. Compounds 1, 2, 4, 5, 6 and 7 exhibited potent antibacterial activities. In particular, sarocladilactone B (2), helvolinic acid (5) and 6-desacetoxy-helvolic acid (6) exhibited strongly Staphylococcus aureus inhibitory activity with minimum inhibitory concentration (MIC) values of 4, 1 and 4 µg/mL, respectively. The structure-activity relationship (SAR) of these compounds was primarily summarized.
Assuntos
Antibacterianos , Ácido Fusídico/análogos & derivados , Hypocreales/química , Oryza/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Ácido Fusídico/química , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologiaRESUMO
Two new helvolic acid analogues (1 and 2) and one new fumagillin derivative containing an octahydroisobenzofuran moiety (3), together with four known compounds (4-7), were isolated from an Aspergillus terreus, isolated from soil collected from Mauna Kea, the highest mountain in Hawaii. Compound 4 was recorded in SciFinder with a CAS Registry Number of 1379525-35-5, but it was not documented in the cited reference (ACS Chem. Biol. 2012, 7, 137). The structures of compounds 1-4 were elucidated by NMR spectroscopy and HRMS and ECD analysis. Compounds 5 and 6 showed significant inhibitory activity against NF-κB with IC50 values of 2.7 ± 2.6 and 6.5 ± 0.8 µM, respectively. Compounds 1 and 2 were active against S. aureus with MICs of 6.25 and 6.25 µg/mL, respectively, while compound 5 inhibited E. coli with an MIC of 3.12 µg/mL.
Assuntos
Antibacterianos/farmacologia , Aspergillus/química , Cicloexanos/farmacologia , Ácidos Graxos Insaturados/farmacologia , Ácido Fusídico/análogos & derivados , NF-kappa B/antagonistas & inibidores , Antibacterianos/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Cicloexanos/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Ácidos Graxos Insaturados/isolamento & purificação , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologia , Células HEK293 , Havaí , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
A new helvolic acid derivative named helvolic acid methyl ester (1), together with two known helvolic acid compounds, helvolic acid (2) and hydrohelvolic acid (3), were isolated from the fermentation of endophytic fungus Fusarium sp. in Ficus carica leaves. Their structures were elucidated and identified by spectroscopic methods. Compounds 1-3 showed potent antifungal and antibacterial activities.
Assuntos
Ficus/microbiologia , Fusarium/metabolismo , Ácido Fusídico/análogos & derivados , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Ácido Fusídico/química , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologiaRESUMO
The majority of antifungal compounds reported so far target the cell wall or cell membrane of fungi, suggesting that other types of antibiotics cannot exert their activity because they cannot penetrate into the cells. Therefore, if the permeability of the cell membrane could be enhanced, many antibiotics might be found to have antifungal activity. We here used the polyene antibiotic nystatin, which binds to ergosterol and forms pores at the cell membrane, to enhance the cellular permeability. In the presence of nystatin, many culture extracts from entomopathogenic fungi displayed antifungal activity. Among all the active extracts, two active components were purified and identified as helvolic acid and terramide A. Because the minimum inhibitory concentration of either compound was reduced four-fold in the presence of nystatin, it can be concluded that this screening method is useful for detecting novel antifungal activity.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/isolamento & purificação , Antifúngicos/farmacologia , Nistatina/farmacologia , Polienos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Dicetopiperazinas/isolamento & purificação , Dicetopiperazinas/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Sinergismo Farmacológico , Ergosterol/química , Fungos/química , Fungos/citologia , Fungos/efeitos dos fármacos , Ácido Fusídico/análogos & derivados , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologia , Lactamas/isolamento & purificação , Lactamas/farmacologia , Testes de Sensibilidade Microbiana , Nistatina/química , Polienos/químicaRESUMO
Studies of the coprophilous fungus Hypocopra rostrata (TTI-0009, NRRL 66178) isolated from a sample of horse dung collected in Texas led to the isolation of three new sesquiterpenoids that we named hypocoprins A-C (1-3), together with the known fungal metabolite helvolic acid. The new metabolites have a distinctive ring system consisting of fused cyclopropane and cyclodecene units not previously reported from a fungal source. Compounds 1 and 3 moderately inhibited growth of Staphylococcus aureus. The structures of these metabolites were assigned mainly by analysis of 2D NMR and HRESITOFMS data. Relative and absolute configurations were assigned by interpretation of NMR J-values and NOESY data and by application of Mosher's method. These results represent the first report of chemistry from any strain of the genus Hypocopra.
Assuntos
Sesquiterpenos/isolamento & purificação , Xylariales/química , Animais , Antifúngicos/farmacologia , Ácido Fusídico/análogos & derivados , Ácido Fusídico/isolamento & purificação , Cavalos , Esterco/microbiologia , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Sesquiterpenos/química , Staphylococcus aureus/efeitos dos fármacos , TexasRESUMO
High-speed counter-current chromatography (HSCCC) was applied for preparative separation of helvolic acid from the crude extract of the endophytic fungus Pichia guilliermondii Ppf9, associated with the medicinal plant Paris polyphylla var. yunnanensis for the first time. The two-phase solvent system consisted of n-hexane-ethyl acetate-methanol-water (4.5:4.5:5.0:5.0, v/v) appending with phosphoric acid (0.2%, v/v) was employed. The revolution speed of the separation column, flow rate of the mobile phase and separation temperature of the apparatus were 800 rpm, 3 ml min(-1) and 25°C, respectively. About 6.8 mg of helvolic acid was successfully obtained from 450 mg of the crude extract by HSCCC within 4 h separation procedure, and its purity reached to 93.2% according to the HPLC analysis. The product was further characterized by MS, (1)H-NMR and (13)C-NMR spectra.
Assuntos
Cromatografia/métodos , Endófitos/química , Ácido Fusídico/análogos & derivados , Pichia/química , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Ácido Fusídico/isolamento & purificação , Espectroscopia de Ressonância Magnética , Magnoliopsida/microbiologia , Dados de Sequência Molecular , Pichia/classificação , Pichia/isolamento & purificação , Análise de Sequência de DNA , Solventes/químicaRESUMO
Details of the fungal biosynthetic pathway to helvolic acid and other fusidane antibiotics remain obscure. During product characterization of oxidosqualene cyclases in Aspergillus fumigatus, we found the long-sought cyclase that makes (17Z)-protosta-17(20),24-dien-3beta-ol, the precursor of helvolic acid. We then identified a gene cluster encoding the pathway to helvolic acid, which is controlled by a transcription regulator (LaeA) associated with fungal virulence. Evidence regarding the evolutionary origin and taxonomic distribution of fusidane biosynthesis is also presented.
Assuntos
Antibacterianos/isolamento & purificação , Aspergillus fumigatus , Ácido Fusídico/análogos & derivados , Transferases Intramoleculares/metabolismo , Triterpenos/isolamento & purificação , Antibacterianos/química , Antibacterianos/farmacologia , Aspergillus fumigatus/química , Aspergillus fumigatus/genética , Aspergillus fumigatus/metabolismo , Ácido Fusídico/química , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologia , Transferases Intramoleculares/genética , Estrutura Molecular , Estereoisomerismo , Triterpenos/químicaRESUMO
A fusidane triterpene, 16-deacetoxy-7-beta-hydroxy-fusidic acid (1), was isolated from a fermentation of the mitosporic fungus Acremonium crotocinigenum. Full unambiguous assignment of all (1)H and (13)C data of 1 was carried out by extensive one- and two-dimensional NMR studies employing HMQC and HMBC spectra. Compound 1 was tested against a panel of multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) strains and showed minimum inhibitory concentration values of 16 microg/ml.
Assuntos
Acremonium/química , Ácido Fusídico/análogos & derivados , Ácido Fusídico/química , Triterpenos/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana Múltipla , Ácido Fusídico/isolamento & purificação , Ácido Fusídico/farmacologia , Resistência a Meticilina , Testes de Sensibilidade Microbiana/métodos , Estrutura Molecular , Staphylococcus aureus/efeitos dos fármacos , Triterpenos/isolamento & purificação , Triterpenos/farmacologiaRESUMO
A spectrophotometric method for assay of fusidic acid is described. The method is based on reaction with a reagent consisting of acetic anhydride and concentrated sulfuric acid. Mathematical processing of the results of the main substance determination in fusidic acid preparations showed that the error did not exceed 2 per cent. Procedures for spectrophotometric assay of fusidic acid in control of the processes of its biosynthesis, isolation and purification were developed. The procedures provided control of the technological process of fusidic acid production.
Assuntos
Indústria Farmacêutica/normas , Ácido Fusídico/análise , Espectrofotometria/métodos , Anidridos Acéticos/farmacologia , Ácido Fusídico/isolamento & purificação , Indicadores e Reagentes/farmacologia , Matemática , Controle de Qualidade , Ácidos Sulfúricos/farmacologia , U.R.S.S.RESUMO
The investigation presents a method of electrophoretic separation of antibacterial drugs which are used in combinations in clinical medicine. Subsequent to electrophoresis in agarose gel, a microbiological assay was performed. This technique permitted the determination of the concentrations of beta-lactam antibiotics, rifampicin, and clindamycin in the presence of aminoglycosides. In therapeutic combinations of fusidic acid and clindamycin, the concentrations of each drug could be determined.