Fig. 1.
Direct scavenging of O2•− by shikonin. Shikonin (final, 0.1–33.0 µM) was added to cuvettes containing 0.1 µM hypoxanthine, 1 µM CLA and 1 mM CaCl2 in RH buffer and then preincubated at 37°C for 5 min before setting in CFL-C2000. The chemiluminescence baseline was monitored for 50 s before addition of xanthine oxidase (final, 2.4 × 10−3 U/ml) to produce O2•−. Scavenging efficiencies were expressed as decreases in the chemiluminescence response (ratios of the areas under the curve, AUCs, of assays with shikonin relative to DMSO-control assays) and shown as a function of shikonin concentration. Values are means ± SD (n = 3). Statistically significant difference between all treatments was determined by one-way ANOVA followed by Dunnett’s test: *p<0.01 vs DMSO-controls.