Moreover, chlorophyll gives an indirect estimation of the nutrient status because

much of the leaf nitrogen is incorporated in chlorophyll (Ferruzzi & Blakeslee, 2007). Antioxidants are substances that counteract free radicals and prevent the damage they cause. These CB-839 molecular weight substances can greatly reduce the damage caused by oxidants by breaking them down before they react with biological targets, preventing either chain reactions or activation of oxygen to give highly reactive products (Ratnam, Ankola, Bhardwaj, Sahana, & Ravi Kumar, 2006). The results in Table 2 show that the concentrated mate extract had better (p < 0.05) antioxidant activity in vitro in comparison to the mate extract. Prudêncio et al. (2012) and Boaventura et al. (2012) also noted substantial ROCK inhibitor differences between DPPH EC50 in the mate aqueous extracts of bark and leaves after concentration processes. The well-known antioxidant activity of Ilex paraguariensis is related to

the presence of several compounds, mainly chlorogenic acid ( Anesini, Turner, Cogoi, & Filip, 2012). However, tests that measure antioxidant activity in vitro do not always show this behaviour in vivo. Wilmsen et al. (2005) reported that the evaluation of antioxidant activity using S. cerevisiae yeast as a biological system model is a quick test that shows representative results for studies of oxidative stress in eukaryotic cells treated with hydrogen peroxide. Both the samples that were evaluated were able to protect the yeast cells against damage caused by hydrogen peroxide (Table 2). Additionally, the results obtained in this present study indicate that the phenolic compounds present in the samples play an important role in antioxidant activity. Differences (p < 0.05) in the survival rates of the S. cerevisiae yeast treated with hydrogen peroxide of mate and concentrated Digestive enzyme mate extracts were noted in this present study. However, antioxidant activity does not seem to depend exclusively on total polyphenol content. As observed by Stefenon et al. (2010) in red sparkling wines, samples

with significant amounts of phenolic compounds did not show the highest antioxidant activity. Medina et al. (2011) also noted there was no correlation with the antioxidant activity measured by DPPH in araçá extract. It is possible that the lower protection of yeast cells against damage caused by hydrogen peroxide is due to condensation reactions influenced by nanofiltration. Halliwell (2008) reported that, under certain experimental conditions and in high concentrations, some polyphenols such as phenolic acids can exert pro-oxidant activities, forming compounds that have toxic effects and may cause cell death. The high concentrations of phenolic compounds in the concentrated mate extract obtained by NF probably explain their lower protective effect over yeast cells.