Screening of the antioxidant and vasorelaxant activity of wine waste ultrasonic extracts, and HRMS targeted and semi-targeted profiling of glycosylated polyphenols vs free polyphenols

The winemaking process generates a large amount of waste which can be profitably converted into a resource. In this work, extracts from stalks, lees, and pomace of Magliocco canino cv (Vitis Vinifera L.) were obtained using ultrasounds. A comprehensive metabolomics profile was carried out by high-resolving power mass spectrometry hyphenated with liquid chromatography. Fifty-nine compounds were annotated and successively verified, bearing different chemical classes. Free amino acids were quantified in the different extracts. Distinction of glycosylated polyphenols vs their aglycones was accomplished by targeted and semi-targeted LC-MS methods; then selected polyphenolic biomarkers were quantified in the studied extracts. The antioxidant activity was evaluated in vitro in a human dermal fibroblasts assay, and the best antioxidant extract was used for the synthesis of an antioxidant DX conjugate by a grafting reaction, to obtain an innovative food ingredient endowed with improved antioxidant activity. The in-vitro endothelium-dependent vasorelaxation, recorded for both stalk and lees extracts could be exploited for the development of new antihypertensive nutraceuticals.