Anti-endotoxic effects of 4(3H)-quinazolinone from Radix Isatidis

OBJECTIVE To study the anti-endotoxic effect of 4(3H)-quinazolinone(QZO) isolated from Radix Isatidis.METHODS QZO was extracted and isolated from Radix Isatidis and diluted into 0.5% solution.The content of endotoxin pretreated with QZO was quantitatively determined using Limulus test.The inhibition of endotoxin-induced fever by QZO was measured in rabbits.The Lipopolysaccharide(LPS)-induced death in mice pretreated with and without QZO was compared.Influence on the LPS-induced release of TNFα and NO in macrophages from mice was studied.RESULTS After pretreatment with QZO,71.31% of endotoxin was destroyed,the endotoxin-induced fever in rabbits decreased significantly;the rate of LPS-induced death in mice dropped from 70% to 30%.The excessive release of TNFα and NO induced by LPS in mice could be inhibited by QZO from Radix Isatidis and the percentage of inhibition was dependent on the dosage.CONCLUSION QZO isolated from Radix Isatidis possesses anti-endotoxic effects.