Flavonoids protect mice from two types of lethal shock induced by endotoxin

The protective effect of flavonoids on two types of lethal endotoxic shock was studied. A lethal endotoxic shock was induced by administration of lipo polysaccharide (LPS) into D-galactosamine (D-GalN)-sensitized mice and anot her one was done by administration of a high dose of LPS into normal mice. Pretreatment with a series of flavonoids protected mice from two types of e ndotoxin lethality. Flavonoid pretreatment reduced the serum tumor necrosis factor-alpha (TNF-alpha.) level in mice injected with D-GalN and LPS, but not in mice injected with a high dose of LPS. TNF-alpha -induced lethal sho ck in D-GalN-sensitized mice was also protected by pretreatment with flavon oids, suggesting that flavonoids augmented the resistance to TNF-alpha leth ality. On the other hand, flavonoids reduced the plasma level of lipid pero xides in mice injected with a high dose of LPS, but not in D-GalN-sensitize d mice. Taken together, these results indicated that flavonoids might prote ct mice from two types of endotoxin lethality. The protective mechanism of flavonoids in each endotoxin lethality is discussed. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.