Most phenolic compounds found in wine can act as antioxidants (Yildirim, Akçay, Güvenç, Altindisli, & Sözmen, 2005). Likewise, residues of wine production are also characterised by high contents of phenolic compounds

due to an incomplete CB-839 chemical structure extraction during wine production. According to Shrikhande (2000), grape extracts consist of anthocyanins from the skin and procyanidins from the seeds. By-products obtained after wine production, such as the seeds or pomace, constitute a cheap source for extraction of antioxidant flavonoids, which can be used as food supplements or in the production of phytochemicals (González-Paramás, Esteban-Ruano, Santos-Buelga, Pascual-Teresa, & Rivas-Gonzalo, 2004). Furthermore, anthocyanins are considered as potential substitutes for synthetic colourants owing to their bright, attractive colour and water solubility, which make them attractive for incorporation into a variety of food systems (Bordignon-Luiz, Gauche, Gris, & Falcão, 2007). Synthetic selleck products phenolic antioxidants such as BHT (buthylated hydroxytoluene), BHA (buthylated hydroxyanisole) and TBHQ (tert-butylhydroxyquinone) effectively inhibit lipid oxidation. However, concern from consumers regarding such additives has motivated investigations into the benefits of natural antioxidants as substitutes for synthetic ones (Formanek et al.,

2001). Most of the pomace formed from the Brazilian wine production, near 59.4 million kg of pomace considering 18 kg pomace/100 L wine, is treated as a residue with low profit uses such as in animal feed and manure. Therefore, the use of this residue as a valuable winery by-product may represent significant

economic gains and prevent or decrease environmental problems caused by grape pomace accumulation (Campos, Leimann, Pedrosa, & Ferreira, 2008). In this context, the aim of this study was to assess the phenolic compounds content and the in vitro antioxidant activity of red grape pomaces resulting from the Brazilian wine production, with a view to exploiting its Immune system potential as a source of natural antioxidants. 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene, linoleic acid, BHT (2,6-di-tert-butyl-4-methylphenol), Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), catechin, epicatechin, gallic acid, quercetin, kaempferol, t-resveratrol and rutin were purchased from Sigma–Aldrich Chemie (Steinheim, Germany). Malvidin-3-glucoside was purchased from Polyphenols Laboratories AS (Sandnes, Norway). Folin–Ciocalteau reagent, 2,4,6-Tris(2-pyridyl)-1,3,5-triazine (TPTZ) and Tween 40 were purchased from Fluka Chemie AG (Buchs, Switzerland). The solvents employed for extraction and HPLC procedures were analytical/HPLC grade and purchased from Merck (São Paulo, Brazil). Red grape pomaces from the following varieties were analysed: Cabernet Sauvignon and Merlot (Vitis vinifera L.), Bordeaux and Isabel (Vitis labrusca L.