Phenolic profile and biological activity of table grapes (Vitis vinifera L.)

C Di Lorenzo,L Regazzoni,G Aldini,D Tomasi,A Bosso,M Dell'Agli,L Bavaresco,P Restani,E Sangiovanni,F Colombo,S Biella,L Peres De Sousa,P Roca

doi:10.1051/bioconf/20191504005

Abstract

Table grapes are largely produced and consumed in the Mediterranean area. Furthermore, in the last years, the commercial interest in table grapes and other non-alcoholic grape products has notably increased worldwide. In addition to the nutritional aspects, polyphenol compounds in fresh grapes could exert positive effects on human health. The aim of this study was the characterization of the phenolic pattern of sixteen grape varieties and the evaluation of the associated antioxidant capacity and anti-inflammatory activity at gastric level. The methods used were: 1) Folin-Cocalteau's assay for the quantification of total polyphenol content; 2) High-Performance Liquid Chromatography (HPLC) coupled with Diode-Array Detector (DAD) to perform the quantitative analysis of grapes phenolic fraction 3) DPPH (1,1,-diphenil-2-picrylhydrazyl) spectrophotometric assay for the assessment of radical scavenging activity; 4) assessment of IL-8 release from human gastric epithelial cells to evaluate the anti-inflammatory activity of grape extracts. Some grapes, including seedless varieties, showed that the phenolic pattern was highly correlated with the biological activities, and, in particular, with peel and seeds portion. These results suggest that selected grape varieties could represent, also for consumers who do not drink wine, a source of healthy compounds potentially able to counteract oxidative stress and gastric inflammation.

Highlights

Grape (Vitis vinifera L.) is one of the most widely produced crops in the world, with approximately 75 million tons produced every year: of them, 45% is used for the production of table grapes, fresh derivatives, or, alternatively, dried grapes [1].Grapes are part of the common diet worldwide and, in recent years, the commercial interest in grape-derived products has grown, due to the decreasing trend of the wine market
As for the anti-inflammatory activity, grapes extracts were assayed for their efficacy in inhibiting IL-8 release from human gastric epithelial cells (AGS): after cellular treatment with TNF-α, IL-8 levels were measured by Enzyme Linked Immunosorbent Assay (ELISA)
Folin-Ciocalteu’s assay In Fig. 1 is reported the total polyphenol content (TPC) of grape samples included in the study

Summary

Introduction

Grapes are part of the common diet worldwide and, in recent years, the commercial interest in grape-derived products has grown, due to the decreasing trend of the wine market. This phenomenon is partially a consequence of the WHO concerns versus alcoholic beverages, considered responsible for the increasing misuse/abuse in young people [2]. In parallel, this market situation has stimulated a considerable interest in nonfermented products, especially table grapes, for their potential positive effects on human health. Chronic inflammatory conditions can generate oxidative stress, which increases NF-kB activation, worsening, in a vicious circle, the pathological condition [7]

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