title: α-Pyrone derivatives, tetra/hexahydroxanthones, and cyclodepsipeptides from two freshwater fungi.
abstract: Eighteen (1-18) and seven (1, 4, 6-8, 17 and 18) compounds were isolated from organic extracts of axenic cultures of two freshwater fungi Clohesyomyces sp. and Clohesyomyces aquaticus (Dothideomycetes, Ascomycota), respectively. Compounds 1-12 belong to the α-pyrone class of natural products, compounds 13 and 14 were tetrahydroxanthones, compounds 15 and 16 were hexahydroxanthones, while compounds 17 and 18 were cyclodepsipeptides. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configurations of compounds 2, 3, 6, and 7 were assigned via a modified Mosher's ester method using1H NMR data. The relative configurations of compounds 14-16 were determined through NOE data. Compounds 1, 2, 6, 8, 13, 14, and 15 were found to inhibit the essential enzyme bacterial peptidyl-tRNA hydrolase (Pth1), with (13; secalonic acid A) being the most potent. Compounds 1 and 4-18 were also evaluated for antimicrobial activity against an array of bacteria and fungi but were found to be inactive.
authors.affiliation: Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid 22110, Jordan.
authors.forename: Tamam
authors.initials: T
authors.lastname: El-Elimat
authors.affiliation: Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, United States.
authors.forename: Huzefa A
authors.initials: HA
authors.lastname: Raja
authors.affiliation: Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, United States.
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Day
authors.affiliation: Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, United States.
authors.forename: Hana
authors.initials: H
authors.lastname: McFeeters
authors.affiliation: Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, United States.
authors.forename: Robert L
authors.initials: RL
authors.lastname: McFeeters
authors.affiliation: Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC 27402, United States. Electronic address: n_oberli@uncg.edu.
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Oberlies
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001203:Ascomycota / Q000737:chemistry* / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects; D018360:Crystallography, X-Ray; D047630:Depsipeptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005618:Fresh Water / Q000382:microbiology*; D005658:Fungi / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D011753:Pyrones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D047630:Depsipeptides; D011753:Pyrones; D044004:Xanthones
keywords: Bacterial peptidyl-tRNA hydrolase; Cyclodepsipeptides; Freshwater fungi; Tetrahydroxanthones; α-Pyrones