The investigation of the metabolites from the endophytic fungus Xylaria sp. YM 311647 in solid fermentation resulted in the isolation of six undescribed compounds, namely xylarioxides A-F, respectively. These included one eremophilane sesquiterpene, three guaiane sesquiterpene glycosides, and two ergostane glycosides. The structures of the compounds were determined by extensive analyses of spectroscopic data, including 1D and 2D NMR, as well as HRESIMS data. The stereochemistry of xylarioxide A was confirmed by X-ray crystallographic analysis. All of the isolated compounds were assayed for their antifungal activities against seven phytopathogenic fungi and two human pathogenic fungi. Among them, xylarioxides A, E and F showed potent activities against the tested phytopathogens. Particularly, xylarioxide E exhibited the highest activity against Gibberella saubinetii, Curvularia lunata, and Colletotrichum gloeosporioides with MIC values of 4, 4, and 8 μg/mL, respectively, which were comparable to the positive control of nystatin. Interestingly, guaiane sesquiterpene glycosides have been rarely reported from fungal sources. Additionally, xylarioxide E represented an unusual naturally occurring 3,4-seco-steroidal glycoside with a seven-membered lactone in ring A
sesquiterpene glycoside, sesquiterpene, Xylariaceae, Xylaria sp., antiphytopathogenic activity, eremophilane, ergostane glycoside, guaiane glycoside
NCBI PubMed ID: 35421432Publication DOI: 10.1016/j.phytochem.2022.113188Journal NLM ID: 0151434Publisher: Elsevier
Correspondence: S.H. Wu
Institutions: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan Institute of Microbiology, School of Life Sciences, Yunnan University, Kunming, 650091, China, School of Chemical Science and Technology, Yunnan University, Kunming, 650091, China
Methods: 13C NMR, 1H NMR, NMR-2D, IR, X-ray, TLC, UV, extraction, optical rotation measurement, CC, fermentation, HR-ESI-MS, cytotoxicity assay, antifungal activity test
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