Quercetin but not luteolin suppresses the induction of lethal shock upon infection of mice with Salmonella typhimurium.

Tumor necrosis factor-alpha (TNF-alpha) is important for the induction of systemic inflammatory responses that lead to lethal shock. Quercetin and luteolin, which differ by one hydroxyl group, are known to suppress the lipopolysaccharide-induced production of TNF-alpha in vitro. We show differing inhibitory effects of quercetin and luteolin on the induction of lethal shock in Salmonella typhimurium aroA-infected mice. In a time- and dose-dependent manner, quercetin reduced the plasma levels of TNF-alpha, lowered bacterial titers in livers, prevented liver damage and prolonged survival, while luteolin had little or no effect. Compared with luteolin, quercetin increased the infiltration of Gr-1(+)CD69(+) neutrophils into the peritoneal cavity and lowered heat shock protein 70 expression. Obviously, the additional hydroxyl group in quercetin is important for suppressing infection-induced lethal shock in mice.