alpha-Pyrone derivatives, tetra/hexahydroxanthones, and cyclodepsipeptides from two freshwater fungi

作者：El Elimat Tamam; Raja Huzefa A; Day Cynthia S; McFeeters Hana; McFeeters Robert L; Oberlies Nicholas H^*

来源：Bioorganic & Medicinal Chemistry, 2017, 25(2): 795-804.

DOI：10.1016/j.bmc.2016.11.059

• Freshwater fungi
• alpha-Pyrones
• Tetrahydroxanthones
• Cyclodepsipeptides
• Bacterial peptidyl-tRNA hydrolase

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 cc-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 using H-1 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.

• 出版日期2017-1-15