title: A new antibacterial dioxopiperazine alkaloid related to gliotoxin from a marine isolate of the fungus Pseudallescheria.
abstract: A new antibacterial dioxopiperazine, dehydroxybisdethiobis(methylthio)gliotoxin (1), and the previously described bisdethiobis(methylthio)gliotoxin (2) and gliotoxin (3), have been isolated from the broth of a marine-derived fungus of the genus Pseudallescheria. The structure and absolute stereochemistry of the new compound was assigned on the basis of NMR and CD experiments. Compounds 1 to approximately 3 exhibit potent antibacterial activity against the methicillin-resistant and multidrug-resistant Staphylococcus aureus with MIC values of 31.2, 31.2, and 1.0 microg/ml, respectively. Compound 3 also exhibited a significant radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with IC50 value of 5.2 microM.
authors.affiliation: Department of Chemistry, Pukyong National University, Busan 608-737, Korea.
authors.forename: Xifeng
authors.initials: X
authors.lastname: Li
authors.forename: Se-Kwon
authors.initials: SK
authors.lastname: Kim
authors.forename: Ki Wan
authors.initials: KW
authors.lastname: Nam
authors.forename: Jung Sook
authors.initials: JS
authors.lastname: Kang
authors.forename: Hong Dae
authors.initials: HD
authors.lastname: Choi
authors.forename: Byeng Wha
authors.initials: BW
authors.lastname: Son
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002942:Circular Dichroism; D016166:Free Radical Scavengers / Q000302:isolation & purification / Q000494:pharmacology; D005912:Gliotoxin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D000459:Phaeophyceae / Q000382:microbiology; D011541:Pseudallescheria / Q000302:isolation & purification / Q000378:metabolism*; D012623:Seawater / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D016166:Free Radical Scavengers; C512210:dehydroxybisdethiobis(methylthio)gliotoxin; D005912:Gliotoxin