Natural Enfumafungin Analogues from Hormonema carpetanum and Their Antifungal Activities

J Nat Prod. 2023 Oct 27;86(10):2407-2413. doi: 10.1021/acs.jnatprod.3c00562. Epub 2023 Oct 18.

Abstract

Ibrexafungerp, an inhibitor of fungal β-(1,3)-d-glucan synthase, represents the first new class of antifungals to be approved in the last 20 years. Ibrexafungerp is a semisynthetic derivative of the naturally occurring triterpene glycoside enfumafungin. In order to search for new analogues of enfumafungin and to probe its biosynthesis, we undertook a reinvestigation of Hormonema carpetanum, which led to the isolation of two new analogues, enfumafungins B and C, together with enfumafungin. Due to the presence of a hemiacetal moiety in the structure, the enfumafungins appear as a mixture of two interconverting epimers during both the purification process and NMR data acquisition. The structure elucidation, including the differentiation of 25S* and 25R* epimers, was completed by combined analyses of NMR and MS spectroscopic data. The discovery of enfumafungins B and C may have implications for enfumafungin biosynthesis. The antifungal activity of enfumafungins B and C was significantly lower than that of enfumafungin, suggesting that the C-2 substituents and the C-19 carboxy acid are important for activity. Molecular docking simulations revealed significant hydrogen bond interactions between enfumafungins and β-(1,3)-d-glucan synthase, which may be useful for developing new antifungal agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents* / chemistry
  • Antifungal Agents* / pharmacology
  • Glycosides / chemistry
  • Molecular Docking Simulation
  • Triterpenes* / chemistry
  • Triterpenes* / pharmacology

Substances

  • Antifungal Agents
  • ibrexafungerp
  • enfumafungin
  • Triterpenes
  • Glycosides

Supplementary concepts

  • Hormonema carpetanum