Anti-endotoxic effects of benzoic acid from Radix Isatidis

Objective To determine the anti-endotoxic effect of benzoic acid isolated from Radix Isatidis.Methods Benzoic acid was extracted and isolated from Radix Isatidis and diluted into 0.25% solution.The content of endotoxin pretreated with benzoic acid was quantitatively determined using Limulus test.The inhibition of endotoxin-induced fever by benzoic acid was measured in rabbits.The Lipopolysaccharide(LPS)-induced death in mice pretreated with and without benzoic acid was compared.Influence on the LPS-induced release of TNF-α and NO in macrophages from mice was studied.Results After the pretreatment with benzoic acid,78% of the endotoxin was destroyed,the endotoxin-induced fever in the rabbits decreased significantly;the rate of LPS-induced death in mice dropped from 70% to 20%.The excessive release of TNF-α and NO induced by LPS in mice could be inhibited by benzoic acid from Radix Isatidis and the percentage of inhibition was dependent on the dosage.Conclusion Benzoic acid isolated from Radix Isatidis had anti-endotoxic effects.