Oxidative Stress, Prooxidants, and Antioxidants: The Interplay

Table 1

Endogenous mediators of oxidative stress.

Leakage of free radicals	Membrane-bound enzymes	NADPH oxidase
	Electron transport systems	Mixed function oxidases
Activation of oxygen	Soluble cell constituents	Transition metals, thiol containing proteins, quinine derivatives, epinephrine, metalloproteins, hemeproteins, and flavoproteins
	Xenobiotic metabolizing enzymes	Cyt P450-dependent monooxygenases, Cyt 𝑏5, and NADPH-dependent cytochrome reductases
ROS generation/propagation	Soluble cytosolic enzymes	Xanthine oxidase, superoxide dismutase, catalase
	Phagocytic cells	Neutrophils, macrophages, and monocytes involved in inflammation, respiratory burst, and removal of toxic molecules
	Local ischemia	Damaged blood supply due to injury or surgery