A New Antifungal Isocoumarin from The Endophytic Fungus Trichoderma Sp. 09 of Myoporum bontioides A. Gray

BACKGROUND: Myoporum bontioides A. Gray is a commonly used medicinal plant in China. Recently, the chemical and bioactive investigations to the endophytic fungi of this plant have led to several new compounds with antimicrobial and cytotoxic activities. To find out more active molecules, the metabolites of an endophytic fungus, Trichoderma sp. 09 from the root of Myoporum bontioides were investigated. MATERIALS AND METHODS: The metabolites were isolated by column chromatography on silica gel, and their structures were elucidated on the basis of spectroscopic analysis[one-dimensional (1D), two-dimensional (2D)-nuclear magnetic resonance (NMR), Mass spectrometry (MS)], and by comparison with the published data. The dilution method was used for the evaluation of antifungal activity. RESULTS: Four metabolites were isolated and identified as: dichlorodiaportinolide (1), dichlorodiaportin (2), diaportinol (3), and diaportin (4). Compounds 1 and 2 showed weak to high antifungal activities against Colletotrichum musae (Berk. and M. A. Curtis) Arx and Rhizoctonia solani Kühn, as compared with the positive control. CONCLUSIONS: Compound 1 was a new isocoumarin being worthy of consideration for the development and research of antifungal agents. SUMMARY: A new isocoumarin named dichlorodiaportinolide, along with dichlorodiaportin, diaportinol, and diaportin were isolated from the endophytic fungus Trichoderma sp. 09 of the root of Myoporum bontioides. Dichlorodiaportinolide and dichlorodiaportin showed weak to high antifungal activities against musae and R. solani (MIC values from 6.25 to 150 μg/mL). Dichlorodiaportinolide and dichlorodiaportin were inactive to P. italic and F. graminearum (MIC values > 200 μg/mL). Abbreviations used: IR: Infrared Radiation, HR-ESI-MS: High resolution electrospray ionization mass spectroscopy, LCMS-IT-TOF: Liquid chromatography mass spectroscopy-Ion trap-Time-of-flight, UV: Ultraviolet-visible, HMBC: Heteronuclear multiple bond correlation, NOE: Nuclear Overhauser effect.