Chemical investigation of the Antarctic lichen-derived fungal strain Acremonium sp. SF-7394 yielded a new amphilectane-type diterpene, acrepseudoterin (1), and a new acorane-type sesquiterpene glycoside, isocordycepoloside A (2). In addition, three known fungal metabolites, (−)-ternatin (3), [D-Leu]-ternatin (4), and pseurotin A (5), were isolated from the EtOAc extract of the fungal strain. Their structures were mainly elucidated by analyzing their NMR and MS data. The absolute configuration of 1 was proposed by electronic circular dichroism calculations, and the absolute configuration of the sugar unit in 2 was determined by a chemical method. The inhibitory effects of the isolated compounds on protein tyrosine phosphatase 1B (PTP1B) were evaluated by enzymatic assays; results indicated that acrepseudoterin (1) and [D-Leu]-ternatin (4) dose-dependently inhibited the enzyme activity with IC50 values of 22.8 ± 1.1 µM and 14.8 ± 0.3 µM, respectively. Moreover, compound 1 was identified as a competitive inhibitor of PTP1B.
Bibliographical noteFunding Information:
Funding: This research was funded by the Korea Polar Research Institute (PE21150).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Acremonium sp
- Antarctic fungal metabolites
ASJC Scopus subject areas
- Analytical Chemistry
- Chemistry (miscellaneous)
- Molecular Medicine
- Pharmaceutical Science
- Drug Discovery
- Physical and Theoretical Chemistry
- Organic Chemistry