Pyrroloacridine alkaloids from Plakortis quasiamphiaster: structures and bioactivity

J Nat Prod. 2007 Jan;70(1):95-9. doi: 10.1021/np060585w.


A re-collection of Plakortis quasiamphiaster from Vanuatu in 2003 resulted in the isolation of three known compounds, plakinidine A (1) and amphiasterins B1 (6) and B2 (7). Also isolated was a new bis-oxygenated pyrroloacridine alkaloid, plakinidine E (8), with a unique O-substitution versus N-substitution at position C-12 in 1. The biological evaluation of the active compounds in two assays provided complementary data. Plakinidine A (1) exhibited cytotoxicity against human colon H-116 cells with an IC50 of 0.23 microg/mL, but there were no effects against the yeast Saccharomyces cerevisiae diploid homozygous deletion strain of topoisomerase I (top1Delta). By contrast, 8 was inactive against H-116 cells but was potent in the yeast halo screen.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkaloids / chemistry
  • Alkaloids / isolation & purification*
  • Alkaloids / pharmacology
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / isolation & purification*
  • Antineoplastic Agents / pharmacology
  • Drug Screening Assays, Antitumor
  • Humans
  • Inhibitory Concentration 50
  • Molecular Structure
  • Plakortis / chemistry*
  • Saccharomyces cerevisiae / drug effects
  • Vanuatu


  • Alkaloids
  • Antineoplastic Agents