5, 1 and 10 mg/ml). The absorbance at 517 nm was measured after 20 min of incubation at 25 °C. In the study, butyl hydroxyanisole (BHA) and ascorbic acid were used as positive controls. The inhibition of DPPH radicals by the samples GW-572016 molecular weight was calculated according to the following equation: DPPH scavenging activity (%) = [1 − absorbance of sample/absorbance of control] × 100. To determine

hydroxyl radical-scavenging activity, the sample solution (0.1 ml) was mixed with 0.8 ml of reaction buffer [0.2 M phosphate buffer (pH 7.4), 1.75 mM deoxyribose, 0.1 mM ferrous ammonium sulphate and 0.1 mM EDTA and 0.1 ml of 1.0 mM ascorbic acid, and 0.1 ml of 10 mM H2O2 was then added to the reaction solution. The reaction solution was incubated for 10 min at 37 °C and then 0.5 ml of 1% thiobarbituric acid and 1 ml of 2.8% trichloroacetic acid were added BTK pathway inhibitor to the mixture. The mixture was boiled for 10 min and cooled on ice. The absorbance of the mixture was measured at

532 nm. The percent inhibition of deoxyribose degradation was calculated using the following equation: hydroxyl radical-scavenging activity (%) = [1 − absorbance of sample/absorbance of control] × 100. The data from antioxidant activities were expressed as means ± standard deviations of three replicate measurements. An analysis of variance (ANOVA) was applied to determine significant differences (p < 0.05) between the results using GraphPad Prism software. The guarana powder was treated with toluene–ethanol, affording 10% of lipids

based on dry powder. Subsequently, the defatted material was treated with methanol-water to remove low-molar-mass compounds (fraction GMW, 3.4% yield based on dry guarana powder). The residue (residue 1) was dried and was sequentially extracted with DMSO (fractions GD-I, GD-II 3-oxoacyl-(acyl-carrier-protein) reductase and GD-III), water at 25 °C (fractions GW-I and GW-II), water at 90 °C (fractions GHW-I and GHW-II), 2 M NaOH (fractions GHA2-I, GHB2-I, GHA2-II and GHB2-II) and then 4 M NaOH (fractions GHA4-I, GHB4-I, GHA4-II and GHB4-II) (Fig. 1). The yield and the total sugar and protein contents of the fractions isolated from the guarana powder are listed in Table 1. The highest yields were observed for the fractions extracted with DMSO, GD-I (28.9%) and GD-II (16.1%). These fractions also had the highest total sugar content: 97% for GD-I and 96% for GD-II. The fractions extracted with water at 25 °C (GW) had the lowest yields, 0.1–0.2%. The hemicellulose fractions, extracted under alkaline conditions, had yields from 0.4% to 2.2%, and hemicelluloses A had higher yields than hemicelluloses B. The total sugar content of the hemicellulose fractions ranged from 26% to 64%. All of the hemicellulose fractions exhibited high protein contents, with values ranging from 23% to 36%, suggesting that the alkali treatment caused disruption of the covalent cross-linking that is present in the cell wall and release of the structural proteins (Morrison, 2001).