New cytotoxic bicyclic hexapeptides, RA-XXIII and RA-XXIV, from Rubia cordifolia L

Chem Pharm Bull (Tokyo). 2008 May;56(5):730-3. doi: 10.1248/cpb.56.730.

Abstract

Two new bicyclic hexapeptides, RA-XXIII and RA-XXIV, were isolated from the roots of Rubia cordifolia L. (Rubiaceae). Their structures were determined by the analysis of their 2D NMR spectra, chemical methods, and X-ray crystallography. The IC50 values of RA-XXIII and RA-XXIV against P-388 leukemia cells were 0.16 and 0.48 microg/ml, respectively.

MeSH terms

  • Ammonia / chemistry
  • Antineoplastic Agents, Phytogenic / isolation & purification*
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Bromine / chemistry
  • Crystallography, X-Ray
  • Magnetic Resonance Spectroscopy
  • Methylation
  • Peptides, Cyclic / isolation & purification
  • Peptides, Cyclic / pharmacology*
  • Plant Roots / chemistry
  • Rubia / chemistry*
  • Spectrometry, Mass, Electrospray Ionization
  • Spectrophotometry, Infrared
  • Spectrophotometry, Ultraviolet

Substances

  • Antineoplastic Agents, Phytogenic
  • Peptides, Cyclic
  • RA-XXIII
  • RA-XXIV
  • Ammonia
  • Bromine