Isolation of new compounds related to xyloketals biosynthesis implies an alternative pathway for furan-fused-chromene formation

Org Biomol Chem. 2023 May 24;21(20):4309-4318. doi: 10.1039/d3ob00426k.

Abstract

In fungi, there is a rare group of natural products harboring the 2,3,3a,9a-tetrahydro-4H-furo[2,3-b]chromene skeleton, represented by xyloketal B, which display a wide range of biological activities and have drawn significant attention. In this work, four new analogues simpliketals A-D (1-4), as well as two other new compounds simplilactones A and B (5 and 6), were isolated from Simplicillium sp. AHK071-01. Their structures were elucidated by extensive NMR spectroscopic methods, 13C NMR calculation, single-crystal X-ray diffraction, and ECD calculation. In addition, five known compounds (7-11) including alboatrin (7) were also obtained. Based on the structural similarity of the above compounds, we inferred that compounds 5, 6, and 8-11 might be biosynthetically related with 1-4 and 7, which allowed us to propose an alternative biosynthetic route to generate the furan-fused chromene skeleton of this class of compounds, instead of a previously presumed polyketide-terpenoid hybrid pathway. Finally, cytotoxicity assays showed that 1-4 exhibited weak inhibitory activity on PANC-1 cells and that 2 and 3 possessed moderate activity against SH-SY5Y cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzopyrans / chemistry
  • Furans
  • Humans
  • Hypocreales*
  • Molecular Structure
  • Neuroblastoma*

Substances

  • Benzopyrans
  • Furans