Evaluation of antiproliferative and anti-inflammatory effects of non-pomace sediment of red grape juices (Vitis labrusca L.) in healthy and cancer cells after in vitro gastrointestinal simulation

Grape polyphenols are studied for their bioactive activities and health benefits. Grape juice clarification produces a colored non-pomace solid residue that is rich in polyphenols and may have potential for nutraceutical applications. This study therefore firstly investigated antiproliferative and anti-inflammatory properties of the non-pomace sediment of Bordo and Isabel grape juices before and after the gastrointestinal simulation, and evaluated the effects of the main individual phenolic compounds found in these sediments in regards to their antiproliferative action in healthy and cancer cells. The non-pomace sediments inhibited significantly the proliferation of colorectal adenocarcinoma cells (Caco-2) cells, whereas their digested fractions inhibited proliferation of hepatocellular carcinoma (HepG2) cells. However, the exposure to treatments caused no cell toxicity to healthy cells. When tested individually, the phenolic compounds quercetin and myricetin showed antiproliferative activity and led to cell viability of 56.47 and 51.07 % in Caco-2 cells and of 33.96 and 27.03 % in HepG2 cells, respectively. The non-pomace sediments and its digested fractions exhibited anti-inflammatory action by inhibiting the release of tumor necrosis factor alpha (TNF-α) in murine macrophages. These encouraging data suggests the potential use of this residue as dietary supplement or as a promising chemotherapy for antitumor therapies.