<p>Presence of hydrogen peroxide was measured by xylenol orange assay. The open bar, initial H<sub>2</sub>O<sub>2</sub> at 1 mM. The solid bar, initial H<sub>2</sub>O<sub>2</sub> at 0.5 mM. Control, H<sub>2</sub>O<sub>2</sub> only. The data was repeated twice with similar results.</p