Four new cyclic tetradecapeptides, verrucamides A-D (1-4), have been isolated from the solid-substrate fermentation culture of the ascomycete fungus Myrothecium verrucaria. The structures of these compounds, each featuring six N-methylated amino acid residues, were elucidated primarily by NMR and MS methods. The absolute configurations of 1-4 were assigned by application of Marfey's method on their acid hydrolysates. Compounds 1-4 showed antimicrobial activity against the Gram-positive bacterium Staphylococcus aureus.
Abstract:A new prenylated indole diketopiperazine alkaloid, cristatumin F (1), and four known metabolites, echinulin (2), dehydroechinulin (3), neoechinulin A (4) and variecolorin O (5), were isolated from the crude extract of the fungus Eurotium cristatum. The structure of 1 was elucidated primarily by NMR and MS methods. The absolute configuration of 1 was assigned using Marfey's method applied to its acid hydrolyzate. Cristatumin F (1) showed modest radical scavenging activity against DPPH radicals, and exhibited marginal attenuation of 3T3L1 pre-adipocytes.
A new dimeric naphtho-γ-pyrone, asperpyrone F (1), along with six known ones, asperpyrones B (2) and C (3), fonsecinones A (4) and B (5), aurasperones A (6) and E (7), have been isolated from the solid culture of the edible fungus Pleurotus ostreatus. The structures of 1-7 were determined mainly by NMR and MS experiments. The absolute configuration of compound 1 was assigned via the circular dichroism (CD) data analysis. Compounds 1-7 showed modest antioxidant and immunomodulatory activities. All compounds were isolated from the fungus P. ostreatus for the first time.
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