AUTHOR=Shi Ting , Li Xiang-Qian , Zheng Li , Zhang Ya-Hui , Dai Jia-Jia , Shang Er-Lei , Yu Yan-Yan , Zhang Yi-Ting , Hu Wen-Peng , Shi Da-Yong 

TITLE=Sesquiterpenoids From the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.688202

DOI=10.3389/fmicb.2021.688202

ISSN=1664-302X

ABSTRACT=<p>The fungal strains <italic>Pseudogymnoascus</italic> are a kind of psychrophilic pathogenic fungi that are ubiquitously distributed in Antarctica, while the studies of their secondary metabolites are infrequent. Systematic research of the metabolites of the fungus <italic>Pseudogymnoascus</italic> sp. HSX2#-11 led to the isolation of six new tremulane sesquiterpenoids pseudotremulanes A–F (<bold>1</bold>–<bold>6</bold>), combined with one known analog 11,12-epoxy-12β-hydroxy-1-tremulen-5-one (<bold>7</bold>), and five known steroids (<bold>8</bold>–<bold>12</bold>). The absolute configurations of the new compounds (<bold>1</bold>–<bold>6</bold>) were elucidated by their ECD spectra and ECD calculations. Compounds <bold>1</bold>–<bold>7</bold> were proved to be isomeride structures with the same chemical formula. Compounds <bold>1</bold>/<bold>2</bold>, <bold>3</bold>/<bold>4</bold>, <bold>1</bold>/<bold>4</bold>, and <bold>2</bold>/<bold>3</bold> were identified as four pairs of epimerides at the locations of C-3, C-3, C-9, and C-9, respectively. Compounds <bold>8</bold> and <bold>9</bold> exhibited cytotoxic activities against human breast cancer (MDA-MB-231), colorectal cancer (HCT116), and hepatoma (HepG2) cell lines. Compounds <bold>9</bold> and <bold>10</bold> also showed antibacterial activities against marine fouling bacteria <italic>Aeromonas salmonicida</italic>. This is the first time to find terpenoids and steroids in the fungal genus <italic>Pseudogymnoascus</italic>.</p>