New Polyketides from the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

Abstract

The species Pseudogymnoascus is known as a psychrophilic pathogenic fungus with a ubiquitous distribution in Antarctica. Meanwhile, the study of its secondary metabolites is infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11, guided by the method of molecular networking, led to the isolation of one novel polyketide, pseudophenone A (1), along with six known analogs (2–7). The structure of the new compound was elucidated by extensive spectroscopic investigation and single-crystal X-ray diffraction. Pseudophenone A (1) is a dimer of diphenyl ketone and diphenyl ether, and there is only one analog of 1 to the best of our knowledge. Compounds 1 and 2 exhibited antibacterial activities against a panel of strains. This is the first time to use molecular networking to study the metabolic profiles of Antarctica fungi.

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

“…This greatly enriches the number and diversity of natural products of the genus Pseudogymnoascus. Except for antimicrobial activities of some of the previously obtained polyketides (Figueroa et al, 2015;Fujita et al, 2021;Shi et al, 2021), no other activities were found in Pseudogymnoascus in previous studies. This study is the first to identify secondary metabolites with cytotoxic activities (8 and 9) in Pseudogymnoascus.…”

“…The extracts of some Pseudogymnoascus strains exhibit potent bioactivities, such as antimicrobial, herbicidal, and antitumoral activities (Henríquez et al, 2014;Gonçalves et al, 2015;Gomes et al, 2018;Ferrarezi et al, 2019). To the best of our knowledge, only 22 natural products, including 6 new compounds, were discovered from Pseudogymnoascus up to now (Figueroa et al, 2015;Guo et al, 2019;Fujita et al, 2021;Shi et al, 2021). More than 70% of the previously isolated structures belong to polyketides; others are alkaloids (13.6%), benzene derivative (9.1%), and fatty acid (4.5%).…”

“…The extracts of some of Pseudogymnoascus strains exhibit potent bioactivities, such as antimicrobial, herbicidal, and antitumoral activities (Henríquez et al, 2014;Gonçalves et al, 2015;Gomes et al, 2018;Ferrarezi et al, 2019). However, only four studies have been done on the secondary metabolites of the genus Pseudogymnoascus until now, as far as we know, and most of the obtained structures focus on polyketides, showing antimicrobial activities (Figueroa et al, 2015;Guo et al, 2019;Fujita et al, 2021;Shi et al, 2021). Rare studies about the secondary metabolites of these fungi enlighten that there is latent space for searching novel compounds.…”

“…Pseudogymnoascus sp. HSX2#-11 was an Antarctic fungus isolated from a soil sample of the Fields Peninsula, which can produce abundant and various secondary metabolites, according to our previous research on the fingerprint spectrum and molecular network of its ethyl acetate extract of the fermentation broth (Shi et al, 2021). Further chemical investigation resulted in the isolation and identification of six new tremulane sesquiterpenoids, pseudotremulanes A-F (1-6), together with one known analog 11,12-epoxy-12β-hydroxy-1-tremulen-5-one (7; Zhou et al, 2008), and five known steroids, ganodermasides A (8), B (9), and D (10; Weng et al, 2010Weng et al, , 2011Feng et al, 2010), and dankasterone B (12;Amagata et al, 2007; Figure 1).…”

Nitrogenous Compounds from the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

“…Pseudogymnoascus sp. HSX2#-11, an Antarctic fungus derived from a soil sample of the Fields Peninsula, which can produce various compounds according to our previous study [ 13 ], was further investigated to search for new secondary metabolites. As a result, one new pyridine derivative, 4-(2-methoxycarbonyl-ethyl)-pyridine-2-carboxylic acid methyl ester ( 1 ), together with one known pyrimidine, thymine ( 2 ) and eight known diketopiperazines ( 3 – 10 ) ( Figure 1 ), were isolated and identified from the potato dextrose agar (PDA) culture broth fermentative extracts of this strain.…”