Killing of Staphylococcus aureus by allylpyrocatechol is potentiated by induction of intracellular oxidative stress and inhibition of catalase activity

APC induced expressions of both sodA and sodM, resulting in increased total SOD activity in S. aureus. Higher sodA expression indicated stress induced intracellularly involving O2−, presumably leading to higher intracellular pools of H2O2. A concommittant decrease in katA expression and catalase activity possibly induced ahpC expression, which was increased the highest in APC-treated cells. Our findings suggest that in the absence of catalase, cells are propelled to seek an alternate pathway involving ahpC to reduce stress invoked by O2− and H2O2. Although APC reduced levels of ROS, significant amounts eluded its antioxidative action and remained intracellularly, which adds to oxidative stress in treated cells.