Alain Brunelle oral presentation (OB1-Thu2-1-3)
3D TOF-SIMS imaging of prenylated stilbenes on Macaranga vedeliana leaves
CNRS Institut de Chimie des Substances Naturelles, 1 Avenue de la Terrasse, 91190 Gif-sur-Yvette, France
Phytochemical studies from Macaranga species led to the discovery of an interesting family of prenylated stilbenes, named schweinfurthins (SWF), having an original hexahydroxanthene moiety. Vedelianin, the first member of this chemical series was isolated from the leaves of Macaranga vedeliana, an endemic New Caledonian species. Studying these molecules is of great interest since they display promising antiproliferative activities at low concentration (nM) for specific tumor-derived cell lines, such as glioblastoma. Currently, the study of these compounds is limited by supply problems. Indeed, the extraction yield is weak and only one total synthesis, requiring 16 steps with a poor overall yield, was achieved to date.
Using a TOF-SIMS IV (ION-TOF GmbH) recently upgraded with an argon cluster ion source for sputtering and a bismuth liquid metal ion source for analysis, we were able to perform for the first time dual beam depth profiling experiments on the surface of leaves and fruits of Macaranga vedeliana, an endemic New Caledonian species.
To prevent in-vacuum explosion of the small glandular trichomes covering fruits and leaves surfaces, and also to be able to analyze their liquid content while preventing any sublimation of the latter, the samples were kept frozen during the whole experiment using a nitrogen cooled sample holder. Thus, we were able to demonstrate that vedelianin is only located in these glandular trichomes.