Grapevine Green Pruning Residues as a Promising and Sustainable Source of Bioactive Phenolic Compounds.

Stefano Acquadro,Silvia Appleton,Patrizia Rubiolo,Carlo Bicchi,Manuela Mandrone,Francesco Gai,Cecilia Cagliero,Arianna Marengo,Barbara Sgorbini,Pier Giorgio Peiretti

doi:10.3390/molecules25030464

Abstract

Green pruning residues (GPRs) and leaves from 16 red and white Vitis vinifera L. cultivars from Piedmont (Italy) were studied. The investigated samples were extracted by ultrasound-assisted extraction optimized by an experimental design, and quali- and quantitatively analyzed by HPLC-PDA-MS/MS. GPRs and leaves show a similar polyphenolic pattern, with quercetin 3-O-glucuronide, caftaric acid, and quercetin 3-O-glucoside as the main components, although in variable proportions. The HPLC results were related to the antioxidant activity, measured as total phenolic content and through DPPH and ABTS assays with similar results. Colorimetric in vitro assays, offline combined with HPLC-PDA analysis, determine which compounds contribute to the antioxidant activity in terms of radical scavenging abilities. Valorization of GPRs is a potential source of natural compounds that could be of interest in the health field, increasing their economic value together with a positive effect on the environment.

Highlights

Wine production and, thereby, grape crops are one of today’s main and most widespread agro-economic activities, with more than seven million hectares cultivated and 77 million tons produced worldwide in 2016 [1]
Taking into account the above considerations, this study aims to investigate the potential of grapevine green pruning residues (GPRs) as a source of antioxidants, by evaluating their phenolic composition and comparing the results with those of the already exploited late-summer leaves
The analyses were performed on both green pruning residues and leaves on samples from the same plants, because only information for the leaves is available from the literature [7,23,27,28]

Summary

Introduction

Thereby, grape crops are one of today’s main and most widespread agro-economic activities, with more than seven million hectares cultivated and 77 million tons produced worldwide in 2016 [1]. Viticulture produces huge amounts of residues, which are a serious economic issue; they are mainly destined to composting or discarded in open areas, potentially causing environmental problems [2]. In the Mediterranean area, and in Italy in particular, wine production and vineyard cultivation are widespread, and result in large amounts of pruning residues waste. In 2011, 3218 million hectares were cultivated as vineyards in Europe [8] of which 736 million hectares were in Italy, for a production of million tons of grapes [9]. Sánchez et al [11]

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