Isolation and Structural Elucidation of Compounds from Natural Products

In continuation of the Kingston group's work to identify new compounds from natural products as a part of the International Cooperative Biodiversity Group (ICBG) program and in collaboration with the Institute for Hepatitis and Virus Research (IHVR), the two plants Neoharmsia baronii and Lopholaena cneorifolia were studied to identify their chemical components. Structural elucidation and characterization of the compounds were done using mass spectrometry, 1D and 2D NMR spectroscopy techniques.

A systematic study of the ethanol extract of the plant Neoharmsia baronii Drake from the Madagascar forest led to the isolation of seven compounds, characterized as isoflavones and pterocarpans. The structures of the compounds were characterized by using 1D NMR and 2D NMR spectra, mass spectroscopy and in one case, x-ray crystallography. The HSQC and HMBC data along with comparison of these data with reported literature values confirmed the structures. The aforementioned isoflavones and pterocarpans showed varying cytotoxicity to ovarian cancer cell lines, with the isoflavone vogelin E being the most active compound.

The extract of Lopholaena cneorifolia was studied as a part of a cooperative project with the IHVR to identify its chemical composition. Fractionation of this extract led to the isolation of three compounds which were characterized as stilbenes. Their structures were elucidated by using 1D NMR and 2D NMR spectra and mass spectroscopic data.