Anti-endotoxic effects of salicylic acid from Radix Isatidis

OBJECTIVE To study the anti-endotoxic effect of salicylic acid isolated from Radix Isatidis.METHODSSalicylic acid was extracted and isolated from Radix Isatidis and diluted into 0.25% solution.The endotoxin pretreated with salicylic acid was quantitatively determined using Limulus test.The inhibition of endotoxin induced fever by salicylic acid was measured in rabbits.The lipopolysaccharide(LPS)-induced death in mice pretreated with and without salicylic acid was compared.Influence on the LPSinduced release of TNFα and NO in macrophages from mice was studied.RESULTSAfter pretreatment with salicylic acid,74.07% of endotoxin was destroyed,the endotoxin-induced fever in rabbits decreased significantly;the rate of LPS-induced death in mice dropped from 70% to 25%;The excessive release of TNFα and NO induced by LPS in mice could be inhibited by salicylic acid from Radix Isatidis and the percentage of inhibition was dependent on the dosage.CONCLUSIONSalicylic acid isolated from Radix Isatidis had anti-endotoxic effects.