Anthraquinones and betaenone derivatives from the sponge-associated fungus Microsphaeropsis species: Novel inhibitors of protein kinases

G Brauers, R A Edrada, R Ebel, P Proksch, V Wray, A Berg, U Grafe, C Schachtele, F Totzke, G Finkenzeller, D Marme, J Kraus, M Munchbach, M Michel, G Bringmann, K Schaumann

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An undescribed fungus of the genus Microsphaeropsis, isolated from the Mediterranean sponge Aplysina aerophoba, produces two new betaenone derivatives (1, 2) and three new 1,3,6,8-tetrahydroxyanthraquinone congeners (5-7). The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data and by CD spectroscopy. This is the first report wherein the H-1 and C-13 NMR data of the betaenone congeners are fully and unambiguously assigned on the basis of two-dimensional NMR spectroscopy. Furthermore, we describe the first elucidation of the absolute configuration of 1-(2'-anthraquinonyl)ethanols such as 5 and 6, by quantum chemical calculation of their circular dichroism (CD) and comparison with experimentally measured spectra. Moreover, it was shown that compounds 1, 5, 6, and 7 are inhibitors of PKC-epsilon, CDK4, and EGF receptor tyrosine kinases.

Original languageEnglish
Pages (from-to)739-745
Number of pages7
JournalJournal of Natural Products
Issue number6
Publication statusPublished - Jun 2000

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