Planta Med 2012; 78 - CL16
DOI: 10.1055/s-0032-1320251

Isolation, synthesis, and bioactivity of Calamenene sesquiterpenoids from Sterculia Capuronii from the Madagascar dry forest

Y Dai 1, L Harinantenaina 1, PJ Brodie 1, M Callmander 2, S Randrianasolo 2, E Rakotobe 2, VE Rasamison 2, DGI Kingston 1
  • 1Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
  • 2Centre National d'Application des Recherches Pharmaceutiques, B.P. 702, Antananarivo 101, Madagascar

During our ongoing research as part of the Madagascar International Cooperative Biodiversity Group (ICBG) program, an EtOH extract of the bark of the plant Sterculia capuronii Arènes (Malvaceae) was found to exhibit anti-proliferative activity against the A2780 human ovarian cancer cell line, with an IC50 value of 14µg/mL. Liquid-liquid partition, LH-20 and silica gel open column chromatography, and C-18 reverse phase HPLC were further applied to this crude extract to obtain a known (1) and two novel calamenene sesquiterpenoids (2 and 3) which display reproducible antiproliferative activity against the A2780 human ovarian cancer cell line, with IC50 values of 10.2µM, 5.8µM and 6.5µM, respectively. The known compound was dereplicated by comparison of its spectroscopic data with literature data, while the structures of the two novel compounds were elucidated by analysis of their 1D and 2D NMR spectra and mass spectrometric data, and confirmed by a de novo synthesis. The relative stereochemistries of 2 and 3 were determined by 1-D NOE difference spectra.