Α-Pyrone derivatives, tetra/hexahydroxanthones, and cyclodepsipeptides from two freshwater fungi. Issue 2 (15th January 2017)

• Record Type: Journal Article
• Authors: El-Elimat, Tamam; Raja, Huzefa A.; Day, Cynthia S.; McFeeters, Hana; McFeeters, Robert L.; Oberlies, Nicholas H.
• Is Part Of: Bioorganic & medicinal chemistry. Volume 25:Issue 2(2017)
• Page Start: 795
• Page End: 804
• Publication Date: 2017-01-15
• Subjects: Freshwater fungi -- α-Pyrones -- Tetrahydroxanthones -- Cyclodepsipeptides -- Bacterial peptidyl-tRNA hydrolase; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; Biochemistry -- Periodicals; Chemistry, Clinical -- Periodicals; Chemistry, Organic -- Periodicals; Chimie bio-organique -- Périodiques; Chimie pharmaceutique -- Périodiques; 615.19
• DOI: 10.1016/j.bmc.2016.11.059
• Languages: English
• ISSNs: 0968-0896

Abstract

Graphical abstract: Abstract: Eighteen (1 –18 ) and seven (1, 4, 6 –8, 17 and18 ) compounds were isolated from organic extracts of axenic cultures of two freshwater fungi Clohesyomyces sp. and Clohesyomyces aquaticus (Dothideomycetes, Ascomycota), respectively. Compounds1 –12 belong to the α-pyrone class of natural products, compounds13 and14 were tetrahydroxanthones, compounds15 and16 were hexahydroxanthones, while compounds17 and18 were cyclodepsipeptides. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configurations of compounds2, 3, 6, and7 were assigned via a modified Mosher's ester method using 1 H NMR data. The relative configurations of compounds14 –16 were determined through NOE data. Compounds1, 2, 6, 8, 13, 14, and15 were found to inhibit the essential enzyme bacterial peptidyl-tRNA hydrolase (Pth1), with (13 ; secalonic acid A) being the most potent. Compounds1 and4 –18 were also evaluated for antimicrobial activity against an array of bacteria and fungi but were found to be inactive.