posted on 2022-12-23, 16:40authored byCunlei Cai, Yingying Chen, Le Zhou, Naying Gong, Hua Zhang, Changli Sun, Junying Ma, Jianhua Ju
Three diphenyl ethers (1–3) and
a cyclopentenone (4), together with seven known compounds
(5–11), were isolated from the fermentation
broth of the marine sediment-derived fungus Spiromastix sp. SCSIO F190. Compounds 3 and 4 were
found to exist as a pair of atropisomers (3a, 3b) and racemates (4a, 4b), respectively.
The planar structures of compounds 1–4 were elucidated on the basis of NMR and HRESIMS data sets. The absolute
configurations of 2 and 3 were determined
by spectroscopic and single-crystal X-ray diffraction analyses, whereas
the configuration of 4 was determined by spectroscopic
and chiral analyses. All compounds, except for 4 and 11, displayed activities against various pathogenic bacteria.
Notably, compounds 1–4, especially 1, exhibited strong activity against Gram-positive bacteria,
including methicillin-resistant bacterial strains of Staphylococcus
aureus (MRSA), Enterococcus faecalis ATCC
29212, and Bacillus subtilis BS01, with MIC values
ranging from 0.5 to 4 μg/mL. Moreover, the structure–activity
relationship analyses of the active compounds and their analogues
revealed the critical structural features correlating to the observed
antimicrobial activities, herein providing insights for antimicrobial
drug development.