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.

Acremonium sp., terpenoids, PTP1B, antarctic fungal metabolites

• Compound ID: 22783
  

  a-D-Glcp-(1-11)-Subst Subst = SMILES C[C@H]1CC[C@@H]({11}[C@](C)(O)CO2)[C@]31[C@H]2C=C(C)CC3

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  Structure type: monomer ; 421.2202 [M+Na]+
  C21H34O7
  Trivial name: isocordycepoloside A
  Compound class: glycoside, sesquiterpene glycoside
  Reference(s) to other database(s): GenDB:NR_131260
  
   
  
  Acremonium sp. SF-7394
  CSDB ID 40981 (all data & tools)