A Nonpolar Blueberry Fraction Blunts NADPH Oxidase Activation in Neuronal Cells Exposed to Tumor Necrosis Factor-α
Figure 2
Nonpolar blueberry fractions exhibit minimal ROS scavenging capacity. Peroxide generation was quantified via Amplex Red in a direct choline oxidation assay, the conversion of choline to betaine and peroxide by choline oxidase. All fluorescence measurements were normalized to an omission of choline, our control (CON). Addition of choline (CHO) caused significant peroxide formation compared to control (*). Neither 5 μg/mL nor 75 μg/ml nonpolar blueberry fraction (NPBB) in the choline oxidation assay displayed any peroxide scavenging capacities compared to 2000 U/ml catalase (CAT) or controls. Note that the lower concentration of NPBB (5 μg/ml) completely abolished ROS formation in SH-SY5Y cells exposed to TNFα or PMA. In contrast, 75 μg/ml of polar blueberry fraction (POBB, **, significantly different from 75 μg/ml NPBB) exhibited considerable peroxide scavenging capacity, which was not observed at a fifteenfold lower concentration (5 μg/ml). Both NPBB and POBB at 5 μg/ml caused an overall reduction of Amplex Red fluorescence (*), which could imply an interference with Amplex Red fluorescence rather than peroxide scavenging. All data represent the mean of at least four independent experiments ± standard deviations, and statistical significance was determined at * (ANOVA and Tukey’s post hoc analysis).
