Fig. 4.
Effects of vitexin on the stress resistance proteins of wild type N2 nematodes. (A) The enzymatic reaction of xanthine with xanthine oxidase was used to generate O2•− and the SOD activity was estimated spectrophotometrically through formazan formation by NBT reduction. SOD activity was expressed as a percentage of the scavenged amount per control. (B) Catalase activity was calculated from the concentration of residual H2O2, as determined by a spectrophotometric method. Catalase activity was expressed in U/mg protein. (C) Intracellular ROS accumulation was quantified spectrometrically at excitation 485 nm and emission 535 nm. Plates were read every 30 min for 2 h. Data are expressed as the mean ± S.E.M. of three independent experiments (N=3). Differences compared to the control were considered significant at *p<0.05, **p<0.01 and ***p<0.001 by one-way ANOVA.