Peptaibols, Tetramic Acid Derivatives, Isocoumarins, and Sesquiterpenes from a Bionectria sp. (MSX 47401)

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• 作者：Mario Figueroa ; Huzefa Raja ; Joseph O. Falkinham ; III ; Audrey F. Adcock ; David J. Kroll ; Mansukh C. Wani ; Cedric J. Pearce ; Nicholas H. Oberlies
• 刊名：Journal of Natural Products
• 出版年：2013
• 出版时间：June 28, 2013
• 年：2013
• 卷：76
• 期：6
• 页码：1007-1015
• 全文大小：440K
• 年卷期：v.76,no.6(June 28, 2013)
• ISSN：1520-6025

文摘

An extract of the filamentous fungus Bionectria sp. (MSX 47401) showed both promising cytotoxic activity (>90% inhibition of H460 cell growth at 20 渭g/mL) and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). A bioactivity-directed fractionation study yielded one new peptaibol (1) and one new tetramic acid derivative (2), and the fungus biosynthesized diverse secondary metabolites with mannose-derived units. Five known compounds were also isolated: clonostachin (3), virgineone (4), virgineone aglycone (5), AGI-7 (6), and 5,6-dihydroxybisabolol (7). Compounds 5 and 7 have not been described previously from natural sources. Compound 1 represents the second member of the peptaibol structural class that contains an ester-linked sugar alcohol (mannitol) instead of an amide-linked amino alcohol, and peptaibols and tetramic acid derivatives have not been isolated previously from the same fungus. The structures of the new compounds were elucidated primarily by high-field NMR (950 and 700 MHz), HRESIMS/MS, and chemical degradations (Marfey鈥檚 analysis). All compounds (except 6) were examined for antibacterial and antifungal activities. Compounds 2, 4, and 5 showed antimicrobial activity against S. aureus and several MRSA isolates.