Unusual derivatives from Hypericum scabrum

Sci Rep. 2021 Jan 14;10(1):22181. doi: 10.1038/s41598-020-79305-y.


Three new compounds (1-3) with unusual skeletons were isolated from the n-hexane extract of the air-dried aerial parts of Hypericum scabrum. Compound 1 represents the first example of an esterified polycyclic polyprenylated acylphloroglucinol that features a unique tricyclo-[,4]-undecane skeleton. Compound 2 is a fairly simple MPAP, but with an unexpected cycloheptane ring decorated with prenyl substituents, and compound 3 has an unusual 5,5-spiroketal lactone core. Their structures were determined by extensive spectroscopic and spectrometric techniques (1D and 2D NMR, HRESI-TOFMS). Absolute configurations were established by ECD calculations, and the absolute structure of 2 was confirmed by a single crystal determination. Plausible biogenetic pathways of compounds 1-3 were also proposed. The in vitro antiprotozoal activity of the compounds against Trypanosoma brucei rhodesiense and Plasmodium falciparum and cytotoxicity against rat myoblast (L6) cells were determined. Compound 1 showed a moderate activity against T. brucei and P. falciparum, with IC50 values of 3.07 and 2.25 μM, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiprotozoal Agents / chemistry
  • Antiprotozoal Agents / pharmacology
  • Biological Products / chemistry*
  • Biological Products / metabolism
  • Biological Products / pharmacology
  • Biosynthetic Pathways
  • Hypericum / chemistry*
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Structure
  • Plant Extracts / biosynthesis
  • Plant Extracts / chemistry*
  • Plant Extracts / pharmacology
  • Structure-Activity Relationship


  • Antiprotozoal Agents
  • Biological Products
  • Plant Extracts