Emeridones A-F, a Series of 3,5-Demethylorsellinic Acid-Based Meroterpenoids with Rearranged Skeletons from an Endophytic Fungus Emericella sp. TJ29

J Org Chem. 2019 Feb 1;84(3):1534-1541. doi: 10.1021/acs.joc.8b02830. Epub 2019 Jan 14.

Abstract

Six new 3,5-demethylorsellinic acid-based meroterpenoids, emeridones A-F (1-6), and eight known analogues (7-14) were isolated from Emericella sp. TJ29. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses, single-crystal X-ray diffraction experiments, and electronic circular dichroism calculations. Emeridone A (1) represents the first meroterpenoid featuring a unique rigid 6/6/5/6 tetracyclic carbon ring system with two additional lactone rings. Emeridones B and C (2 and 3) possess a 2,6-dioxabicyclo[2.2.1]heptane and a spiro[bicyclo[3.2.2]nonane-2,1'-cyclohexane] moiety, respectively, and both functionalities were found for the second time in meroterpenoids. These new compounds were evaluated for their cytotoxic activities against five human cancer cells, and compounds 2, 4, and 6 exhibited moderate cytotoxic activities, with IC50 values ranging from 8.19 to 18.80 μM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biochemical Phenomena
  • Circular Dichroism / methods*
  • Crystallography, X-Ray
  • Emericella / chemistry*
  • Humans
  • Inhibitory Concentration 50