OBJECTIVE To analyse the plasma concentration-toxicity relationship in vivo based on the hepatotoxicity of Euodiae Fructus and to further reveal its hepatotoxicity.

METHODS The contents of evodiamine, rutaecarpine and limonin in the aqueous extract of Euodiae Fructus were determined using UPLC. The plasma concentration of limonin was determined in mice with hepatotoxicity induced by Euodiae Fructus aqueous extract using LC-MS/MS. The mice were divided into 3 groups: the Euodiae Fructus aqueous extract group, which was given a gavage dose of 60 g·kg⁻¹, and 2 limonin groups, one given a gavage dose of 200 mg·kg⁻¹ and the other an intraperitoneal injection at the same dose. The plasma concentration of limonin was measured at various time points before and after administration via blood collection.

RESULTS The contents of evodiamine, rutaecarpine and limonin in the aqueous extract of Euodiae Fructus were 0.08%, 0.04% and 1.09%, respectively. Plasma concentration tests showed that the gavage group of limonin had the lowest C_max and AUC_(0-t) without causing significant hepatotoxicity, with a C_max of (32.1±14.5)ng·mL⁻¹ and an AUC_(0-t) of (138.5±139.3)h·ng·mL⁻¹, and the same dose of limonin injected intraperitoneally group increased both C_max and AUC_(0-t) in case of causing significant hepatotoxicity, with a C_max of (1080.0±296.3)ng·mL⁻¹ and an AUC_(0-t) of (10234.5±6917.3)h·ng·mL⁻¹, and the highest C_max and AUC_(0-t) were observed in the gavage group of the aqueous extract of Euodiae Fructus in the case of causing significant hepatotoxicity, with a C_max of (11130.0±3047.8)ng·mL⁻¹ and an AUC_(0-t) of (91797.2±31524.4)h·ng·mL⁻¹.

CONCLUSION The more severe the hepatotoxicity caused by Euodiae Fructus, the higher limonin plasma concentration, and limonin is a key marker for quality control of Euodiae Fructus.