2 2 azobis 2 methylpropionamide dihydrochloride

Sodium arsenite (Merck, Germany), cadmium chloride (Sigma-Aldrich, USA) and mercury chloride (BDH, UK) were prepared in deionised water. BBL™ FTA hemagglutination buffer was obtained from BD (France) and used to prepare phosphate-buffered saline (PBS).
Hank's Buffered Salt Solution (HBSS) was purchased from Life Technologies (South Africa). Penicillin (10,000 IU) and streptomycin (10 mg/mL) solutions were obtained from BioWhittaker (Walkersville, USA). Acetyl-Asp-Glu-Val-Asp-7-amido-4-methylcoumarin (Ac-DEVD-AMC), ATP Assay Kit MAK135, 2,2'-azobis (2-methylpropionamide) dihydrochloride (AAPH), camptothecin, 3-[(3-chloamidopropyl)dimethylammonio]-1-propanesulfonate, 2',7'dihydrodichlorofluorescein diacetate (H2-DCF-DA), Dulbecco's Modified Eagle's Medium (DMEM), ethylenediaminetetraacetic acid (EDTA), HEPES, JC-1, monochlorobimane, nethylmaleimide, phenylmethylsulfonyl fluoride (PMSF), rotenone, saponin, staurosporine, sulforhodamine B (SRB), trypsin, Tris-base and trypan blue were obtained from Sigma-Aldrich (St. Louis, USA). β-Mercaptoethanol and trichloroacetic acid (TCA) was obtained from Merck Chemicals (Darmstadt, Germany). Foetal calf serum (FCS) was procured from PAA (Pasching, Austria).

Grape pomace from red Tempranillo grape was kindly given by Bodega Matarromera (Spain). It corresponded to 2014 vintage. Grape pomace was stored at -18ºC to preserve its antioxidant activity. Samples were thawed overnight at 4ºC before use. A mixed solvent of 50% ethanol and acid water was employed for extraction. Water was acidified with sulphuric acid to pH=1 in order to improve polyphenol stability.
Chemical reagents Folin-Ciocalteu, potassium chloride, sodium acetate, and sodium carbonate were purchased from Panreac Química (Barcelona, Spain). HPLC standards were bought in Extrasynthese (Lyon, France). Cell culture media and supplements, namely RPMI 1640medium, fetal bovine serum (FBS), penicillin-streptomycin and trypsin/ethylenediamine tetraacetic acid (EDTA) were purchased from Invitrogen (Gibco, Invitrogen Corporation, Paisley, UK). For cytotoxicity and antioxidant activity assays, phosphate buffer solution (PBS) was prepared using the phosphate buffered saline powder, 3-(4,5-dimetylthiazol-2-yl)-5-(3-carboxylmethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), 2´,7´-dichlorofluorescin diacetate (≥ 97%), quercetin (≥ 97%) and 2,2′-azobis (2-methyl-propionamide) dihydrochloride (AAPH, 97%) were provided by Sigma-Aldrich (St Louis, MO, USA).