To reveal the processing mechanism of Chrysanthemi Flos from the changes of chemical compositions after frying and its effect on the efficacy of liver protection. Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry(UPLC-Q-TOF-MS) and ultra high performance liquid chromatography(HPLC) were used for the qualitative and quantitative researches of chemical compositions before and after Chrysanthemi Flos frying. Progenesis QI and SPSS software were used for principal component analysis(PCA), partial least squares discriminant analysis(PLS-DA), variable importance projection(VIP) analysis and t-test to identify the compositions with significant changes. Pharmacodynamics experiment was used to investigate the protective effect of crude and fried Chrysanthemi Flos on CCl_4-induced acute liver injury in mice. According to mass spectrometry data, there were 28 chemical compositions in crude and fried Chrysanthemi Flos, mainly including flavonoids and organic acids. 13 compositions such as luteolin, apigenin and luteolin glycoside were increased significantly after frying, while 7 compositions such as chlorogenic acid, luteolin-7-O-glucuronide and apigenin-7-O-glucuronide were decreased significantly after frying. Through principal component analysis, crude and fried Chrysanthemi Flos products were divided into two categories, indicating that there were internal differences in quality. The results of liver injury protection experiment in mice showed that the AST, ALT and MDA contents were significantly decreased and SOD level was increased in mice with liver injury in both the high and medium dose groups. Histopathological examination showed that crude and fried Chrysanthemi Flos can protect the liver by reducing inflammatory cell infiltration, reducing steatosis, and repairing damaged liver cells. The results of this study showed that the chemical compositions had obvious changes after frying, and both crude and fried Chrysanthemis Flos had protective effects on CCl_4-induced acute liver injury in mice. In addition, in the range of high, medium and low doses, the liver protection effect of crude and fried Chrysanthemi Flos increased with the increase of dose. The experiment results provided reference for the mechanism of fried Chrysanthemi Flos and clinical selection of processed products.
Keywords: CCl_4-induced acute liver injury; Chrysanthemi Flos; UPLC-Q-TOF-MS; chemical composition; fried Chrysanthemi Flos.