Antifungal compounds from Vitis vinifera canes against major grapevine fungal pathogens

Worldwide the vast majority of grapevine areas are planted with Vitis vinifera cultivars that are all susceptible to various fungal diseases such as downy (Plasmopara viticola) and powdery (Erysiphe necator) mildews and grey mould (Botrytis cinerea). Since V. vinifera canes represent an unexploited agronomical waste material, their biological activity against the major grapevine pathogens and their chemical content were investigated in order to determine if extracts or compounds could be potentially used in a sustainable manner to protect grapevines. Methanolic and ethanolic crude extracts of Vitis vinifera canes exhibited significant antifungal activity against the three major fungal pathogens of grapevine: P. viticola, E. necator and B. cinerea. The active extract was analysed by LC-PDA-ESI-MS and some compounds were dereplicated. SPE-fractionation combined with the different antifungal assays enabled the localisation of the active zone in the HPLC chromatogram. Efficient targeted isolation using medium pressure liquid chromatography (MPLC-UV) afforded in one step six pure constituents (Ampelopsin A, Hopeaphenol, trans-resveratrol, Ampelopsin H, ε-viniferin and E-vitisin B). The structures of the isolated compounds were elucidated by 2D NMR and HR-MS. Six identified compounds presented interesting antifungal activities against P. viticola.

Acknowledgements: Réflexion scientifique et technique des Neuf, Bordeaux, France.