cerevisiae strain XV185-14c (MATα, ade2-2, arg4-17, his1-7, lys1-1, trp5-48, hom3-10). Yeast cell suspensions containing 2 × 107 cells/mL (exponential phase) were treated with 75 mM hydrogen peroxide, in the presence of concentrated and mate extracts. This dilution was the highest non-cytotoxic concentration of both extracts determined in preliminary assays. The tubes were incubated for 1 h at 28 °C. The samples were then serially diluted in saline solution (0.9% w/v), plated onto YPD (10 g/L of yeast extract, 20 g/L of peptone, 20 g/L of dextrose and 20 g/L of agar–agar) and incubated at 28 °C for 48 h. After incubation, the colonies were counted, and 100% survival was considered
the total number of colonies observed on the control plate (untreated cells)
( Wilmsen, Spada, & Salvador, 2005). All the data were evaluated Akt inhibitor review learn more using the software STATISTICA version 6.0 (2001) (StatSoft Inc., Tulsa, OK) and expressed as mean ± standard deviation (SD) of triplicate measurements. Tukey’s studentised range test was carried out to test for any significant differences between the mate extract and concentrated mate extract. A difference was considered statistically significant when p < 0.05. The chemical compositions of the mate extract and the concentrated mate extract are shown in Table 1. Significant changes occur in the concentration of bioactive compounds of mate extract after nanofiltration (NF). Concentration by NF does not occur only because of the MWCO of the membrane; it can also occur because of the common structural properties of hydrophobic compounds, which generally include aromatic (benzene) ring structures that have aliphatic carbon groups which, Lck if undissociated in pH conditions lower than their pKa values, can be readily adsorbed in this kind of hydrophobic membrane ( Yoon, Westerhoff, Snyder, & Wert, 2006). As noted by Murakami et al. (2011) and by Prudêncio et al. (2012) with mate leaf extract and
mate bark extract, in this present study it was possible to concentrate bioactive compounds from mate extract by NF (Table 1). The content of chlorogenic acid was determined because it is present in higher concentrations in mate (Pagliosa et al., 2010). Fig. 2(a) shows a representative HPLC-DAD chromatogram of chlorogenic acid identified and quantified in the mate samples. The same behaviour obtained by Murakami et al. (2011) was verified in this present study, i.e., the concentration of chlorogenic acid increased after nanofiltration. The methylxanthine content in the concentrated mate extract was higher (p < 0.05) than in the mate extract. Fig. 2(b) shows a representative HPLC-DAD chromatogram of the methylxanthines identified and quantified in the mate samples. After nanofiltration, the concentration of theobromine (323%) increased more than the concentration of caffeine (251%). As expected, the theobromine content was much lower than the caffeine content in both extracts.