title: Cytotoxic effects of stem bark extracts and pure compounds from Margaritaria discoidea on human ovarian cancer cell lines.
abstract: Margaritaria discoidea (Baill.) G. L. Webster (Euphorbiaceae) is a well-known medicinal plant in Africa used for the treatment of various diseases. So far, no cytotoxic effects of plant extracts on cancer cell lines have been reported.
  
  
  OBJECTIVE
  To evaluate the cytotoxicity against human ovarian cancer cells of extracts of M. discoidea and characterize the major bioactive compounds.
  
  
  METHODS
  Both organic and aqueous extracts of this plant were obtained by maceration. The sulforhodamine B cell proliferation assay was used for evaluation of their cytotoxic activities and the potential bioactive compounds were characterized by gas chromatography-mass spectrometry.
  
  
  RESULTS
  The organic extract of M. discoidea showed stronger cytotoxicity than the aqueous extract with IC50 values of 14.4±3.0, 14.2±1.2 and 34.7±0.5µg/ml on OVCAR-8, A2780 and cisplatin-resistant A2780cis ovarian cancer cells, respectively. The organic extract was further subjected to bioassay-guided fractionation by partitioning with n-hexane, ethyl acetate, and n-butanol in water. The ethyl acetate fraction was the most potent on the three ovarian cancer cell lines. A GC-MS analysis of trimethylsilyl derivatives of this fraction indicated the presence of phenolic compounds such as gallic acid and the alkaloid securinine. The IC50 values of these two compounds were determined to be in the range of 3-16µM, which indicated that they could contribute to the cytotoxic activity of the extract of M. discoidea.
  
  
  CONCLUSIONS
  This study has evaluated the cytotoxicity of stem bark extracts of M. discoidea against ovarian cancer cells and provided a basis of further development of this plant for the treatment of ovarian cancer.
authors: Guy Hilton Research Centre, Institute for Science and Technology in Medicine, Keele University, Thornburrow Drive, ST4 7QB Stoke-on-Trent, United Kingdom.
authors: Okiemute Rosa
authors: OR
authors: Johnson-Ajinwo
authors: Guy Hilton Research Centre, Institute for Science and Technology in Medicine, Keele University, Thornburrow Drive, ST4 7QB Stoke-on-Trent, United Kingdom.
authors: Alan
authors: A
authors: Richardson
authors: Guy Hilton Research Centre, Institute for Science and Technology in Medicine, Keele University, Thornburrow Drive, ST4 7QB Stoke-on-Trent, United Kingdom. Electronic address: w.li@keele.ac.uk.
authors: Wen-Wu
authors: WW
authors: Li
mesh_terms: D045744:Cell Line, Tumor / Q000187:drug effects; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D020128:Inhibitory Concentration 50; D019684:Magnoliopsida / Q000737:chemistry*; D010051:Ovarian Neoplasms / Q000473:pathology*; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry
chemical_list: D010936:Plant Extracts
keywords: GC–MS; Gallic acid; Margaritaria discoidea; Ovarian cancer; Securinine