Uncommon N-Methoxyindolediketopiperazines from Acrostalagmus luteoalbus, a Marine Algal Isolate of Endophytic Fungus


Cao J., Li X., Li X., Li H., KONUKLUGİL B., Wang B.

Chinese Journal of Chemistry, vol.39, no.10, pp.2808-2814, 2021 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 39 Issue: 10
  • Publication Date: 2021
  • Doi Number: 10.1002/cjoc.202100368
  • Journal Name: Chinese Journal of Chemistry
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Applied Science & Technology Source, Chemical Abstracts Core
  • Page Numbers: pp.2808-2814
  • Keywords: Marine alga, Endophytic fungus, Acrostalagmus luteoalbus, Natural products, Biological activity, BIOLOGICAL-ACTIVITIES, VERTICILLIN, METABOLITES, DERIVATIVES, DIVERSITY, ALKALOIDS

Abstract

© 2021 SIOC, CAS, Shanghai and Wiley-VCH GmbHFour new N-methoxyindolediketopiperazines (acrozines D—G, 1—4) and six known congeners (5—10) were purified from the organic extract of Acrostalagmus luteoalbus TK-43, which was a marine algal-derived fungus obtained from Codium fragile. Their structures were determined by interpretation of NMR and mass spectroscopic data. The structures of compounds 1, 2, and 4 including their absolute configurations were confirmed by single-crystal X-ray diffraction, while the absolute configuration of compound 3 was elucidated by comparative analysis of ECD and TDDFT-ECD calculations. Compounds 1—4, with a unique methoxy substitution at N-2, were rarely discovered among indolediketopiperazine alkaloids. All these compounds were evaluated for antimicrobial activities against human- and aquatic-pathogenic bacteria and plant-related pathogenic fungi, with compounds 5 and 7 exhibiting potent activity against Edwardsiella icataluri (MIC = 3 and 5 μmol/L, respectively), while compound 9 displayed a broad spectrum of antibacterial activities. The four new compounds were further tested for anti-acetylcholinesterase (AChE) properties, and compound 3 exhibited inhibitory activity with IC50 value of 8.4 μmol/L.