Approaches to antiproliferatve agents from Metaporana sericosepala from the Madagascar dry forest

The plant Metaporana sericosepala (Convolvulaceae) is endemic to Madagascar, and no phytochemical studies have previously been made on any members of the genus. In our ongoing research as part of the Madagascar International Cooperative Biodiversity Group (ICBG) program, a sample of M. sericosepala was collected in 2007 in the Diana region of northeast Madagascar. The plant was a climbing vine with white flowers, growing in the dry deciduous Amboahangibe Forest. An ethanol extract of its stems was found to exhibit anti-proliferative activity against the A2780 human ovarian cancer cell line, with an IC₅₀ value of 20µg/mL. Bioassay guided liquid-liquid partition, followed by C-18 solid phase extraction of the dichloromethane fraction (IC₅₀ 14µg/mL) and reverse phase C-18 HPLC led to the isolation of near-homogeneous fractions with moderate antiproliferative activity against the A2780 human ovarian cancer cell line. Final purification of these active fractions and structure elucidation of the purified bioactive compounds by 1D- and 2D-NMR spectroscopy are in progress, and the results of these studies will be reported.