Mode of action of endotoxin: role of free radicals and antioxidants.

The pathogenetic sequence of reactions mediated by endotoxin (LPS) leading to the production of sepsis involves the oxygen radicals or reactive oxygen species, which has been evaluated in the present review. Among reactive oxygen species hydroxyl radical either singly or in combination with peroxynitrite, produces tissue damage often observed during septic injury. Inactivation of these damaging radicals by antioxidants or nitric oxide inhibitor(s) may be helpful for protecting sepsis mediated derangements but the application of these agents as drugs in humans has not been fully successful. Transcription factor NF-kappa B is reported to be the oxygen sensor in LPS induced endotoxemia. Polyphenols, especially the catechin group of compounds, are important therapeutic agents, which may be used for the treatment of endotoxin mediated sepsis.