RESUMO
Fungi have become an invaluable source of bioactive natural products, with more than 5 million species of fungi spanning the globe. Fractionation of crude extract of Neodidymelliopsis sp., led to the isolation of a novel polyketide, (2Z)-cillifuranone (1) and five previously reported natural products, (2E)-cillifuranone (2), taiwapyrone (3), xylariolide D (4), pachybasin (5), and N-(5-hydroxypentyl)acetamide (6). It was discovered that (2Z)-cillifuranone (1) was particularly sensitive to ambient temperature and light resulting in isomerisation to (2E)-cillifuranone (2). Structure elucidation of all the natural products were conducted by NMR spectroscopic techniques. The antimicrobial activity of 2, 3, and 5 were evaluated against a variety of bacterial and fungal pathogens. A sodium [1-13C] acetate labelling study was conducted on Neodidymelliopsis sp. and confirmed that pachybasin is biosynthesised through the acetate polyketide pathway.
Assuntos
Ascomicetos/metabolismo , Produtos Biológicos/química , Policetídeos/isolamento & purificação , Acetamidas/química , Antraquinonas/química , Antibacterianos/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bactérias/metabolismo , Isótopos de Carbono/química , Fermentação , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Policetídeos/química , Sódio/química , Acetato de Sódio , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Antimicrobial bioassay-guided fractionation of the endophytic fungi Neofusicoccum australe led to the isolation of a new unsymmetrical naphthoquinone dimer, neofusnaphthoquinone B (1), along with four known natural products (2-5). Structure elucidation was conducted by nuclear magnetic resonance (NMR) spectroscopic methods, and the antimicrobial activity of all the natural products was investigated, revealing 1 to be moderately active towards methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 16 µg/mL.
