Plant extracts having interesting in vitro and/or in vivo activities are subject to bio and chimio- guided fractionations to identify active components which could constitute new leads for further developments.
Fractions obtained by different chromatographic methods are evaluated and active ones analysed by LC-MS to identify well known compounds (based on retention times and MSn spectra, collaboration with MASSMET platform) and determine those which should be further purified (unidentified substances). The use of molecular networks will also help identifying known compounds. Structural identification is based on UV, IR, SM, 1D and 2DNMR spectra.
In addition to known compounds, we identified several new molecules which are found for the first time in plants. Among them, we can point out diterpenes isolated from Croton zambesicus. Some of these diterpenes have been shown by our team to possess cytotoxic and pro-apoptotic properties but others relax significantly rat aorta contracted by KCl. Comparison of the cytotoxic and vasorelaxant activities of isolated molecules and synthetic analogues indicates that both effects are not linked. We can also cite several promising specific antiparasitic terpenic derivatives isolated form Keetia leucantha, Ocimum basilicum, Vitellaria paradoxa or Cymbopogon species or essential oil components from Vietnamese plants.
Identifications of antimalarial compounds is also guided by supervised metabolomics studies of crude extracts (collaboration with Prof. Choi, Leiden) while collaborations with LIST (Luxembourg Institute of Science and Technology, Dr André) allowed us to identify and produce potential bioactive compounds from in vitro plant cell cultures.