American Chemical Society
np3c00984_si_002.cif (240.91 kB)

Microascones, Decahydrofluorene-Class Alkaloids from the Marine-Derived Fungus Microascus sp. SCSIO 41821

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posted on 2024-03-01, 20:16 authored by Fei-Hua Yao, Xiao Liang, Wen-Bin Shen, Xin-Hua Lu, Guo-Chao Li, Shu-Hua Qi
Eight new decahydrofluorene-class alkaloids, microascones A and B (1 and 2), 2,3-epoxyphomapyrrolidone C (3), 14,16-epiascomylactam B (4), 24-hydroxyphomapyrrolidone A (5), and microascones C–E (68), along with five known analogs (913) were isolated from the marine-derived fungus Microascus sp. SCSIO 41821. Compounds 1 and 2 have an unprecedented complex macrocyclic alkaloid skeleton with a 6/5/6/5/6/5/13 polycyclic system. Their structures and absolute configurations were determined by spectroscopic analysis, quantum chemical calculations of ECD spectra, and 13C NMR chemical shifts. Compounds 1013 showed selective enzyme inhibitory activity against PTPSig, PTP1B, and CDC25B, and 4, 9, and 10 exhibited strong antibacterial activity against seven tested pathogens. Their structure–bioactivity relationship was discussed, and a plausible biosynthetic pathway for 18 was also proposed.