title: A new diketopiperazine alkaloid from Aspergillus oryzae.
abstract: Investigation of bioactive secondary metabolites from terrestrial Aspergillus oryzae sp. MMAO1 using M2 medium afforded a new diketopiperazine alkaloid, 7,9-dihydroxy-3-(1H-indol-3-ylmethyl)-8-methoxy-2,3,11,11a-tetrahydro-6H-pyrazino[1,2-b]isoquinoline-1,4-dione (1a), containing the unusual amino acid L-6,8-dihydroxy-7-methoxyphenylalanine. This was co-isolated with ditryptophenaline (2), cyclo-(Tryp,Tyr) (4), cyclo-(Pro,Val), α-cyclopiazonic acid (3), kojic acid and uridine. Re-cultivation of the fungal strain on Dox medium led to the production of bisdethio(bismethylthio)gliotoxin (5), pseurotin A (6) along with linoleic acid, α-cyclopiazonic acid (3) and kojic acid. The chemical structure of the new diketopiperazine alkaloid including the relative configuration was determined by 1D and 2D NMR spectroscopy and HR-ESI-MS spectrometry, and by comparison with the related literature. The new alkaloid (1a) showed no antimicrobial activity or cytotoxicity against brine shrimps.
authors.affiliation: a Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstrasse 2, D-37077 Göttingen , Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Shaaban
authors.forename: Mohammad Magdy
authors.initials: MM
authors.lastname: El-Metwally
authors.forename: Hamdi
authors.initials: H
authors.lastname: Nasr
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001156:Artemia / Q000187:drug effects; D001236:Aspergillus oryzae / Q000737:chemistry*; D054659:Diketopiperazines / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D012275:Oryza / Q000382:microbiology; D011753:Pyrones / Q000737:chemistry; D011760:Pyrrolidinones / Q000737:chemistry / Q000302:isolation & purification; D014529:Uridine / Q000737:chemistry
chemical_list: C000590621:7,9-dihydroxy-3-(1H-indol-3-ylmethyl)-8-methoxy-2,3,11,11a-tetrahydro-6H-pyrazino(1,2-b)isoquinoline-1,4-dione; D000470:Alkaloids; D000935:Antifungal Agents; D054659:Diketopiperazines; D011753:Pyrones; D011760:Pyrrolidinones; C012013:pseurotin; C011890:kojic acid; D014529:Uridine