Dr Magdalena Malinowska

Grape canes are waste biomass of viticulture containing bioactive polyphenols valuable in cosmetics. Whereas several studies reported the cosmetic activities of E-resveratrol, only few described the potential of E-ε-viniferin, the second major constituent of grape cane extracts (GCE), and none of them investigated GCE as a natural blend of polyphenols for cosmetic applications. In this study, we considered the potential of GCE from polyphenol-rich grape varieties as multifunctional cosmetic ingredients. HPLC analysis was performed to quantify major polyphenols in GCE i.e., catechin, epicatechin, E-resveratrol, E-piceatannol, ampelopsin A, E-ε-viniferin, hopeaphenol, isohopeaphenol, E-miyabenol C and E-vitisin B from selected cultivars. Skin whitening potential through tyrosinase inhibition assay and the activation capacity of cell longevity protein (SIRT1) of GCE were compared to pure E-resveratrol and E-ε-viniferin. Drug-likeness of GCE polyphenols were calculated, allowing the prediction of skin permeability and bioavailability. Finally, the present data enabled the consideration of GCE from polyphenol-rich varieties as multifunctional cosmetic ingredients in accordance with green chemistry practices.

Grape canes are under-valued byproducts of viticulture that accumulate large amounts of stilbenoids. These specialized metabolites are phytoalexins of Vitis vinifera that play a keyrole in defence of Vitis vinifera against pathogens. Since in vitro assays demonstrated the antifungal activity of several pure stilbenoids, grape cane extracts (GCE) have been proposed as eco-friendly alternative to classical fungicides in a context of sustainable viticulture. Following the grape pruning during winter, a storage period associated to an efficient extraction procedure, are determinant to obtain GCE with optimal stilbenoid titration. Stilbenoid-enriched extracts have shown promising protection in vitro against various grape pathogens including downy mildew, powdery mildew, gray mold and wood diseases. Additionally, large-scale studies in vineyards reported a significant partial protection against downy mildew. Protection level is relative to the concentration of stilbenoids contained in the grape cane extract. Therefore, the huge varietal diversity of grape could be explored to select high-producing varieties for future use as biocontrol agent.