This study aims to compare the metabolic differences of baicalin and its analogues between Shuganning Injection and Scutellariae Radix extract. Twelve SD rats were randomly divided into a Shuganning Injection group and a Scutellariae Radix extract group, with 6 rats in each group. Their liver microsomes were incubated with the drugs, and then the samples were collected. Ultra performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry(UPLC-Q-Exactive Orbitrap-MS) was used to analyze the prototype components and metabolites of the drugs in liver microsomes of each group. Another 12 SD rats were also divided into a Shuganning Injection group and a Scutellariae Radix extract group, with 6 rats in each group. The rats were administrated with 4.2 mL·kg~(-1) Shuganning Injection or Scutellariae Radix extract by tail vein injection. After 48 h, the rat urine, feces, and bile were collected, and UPLC-Q-Exactive Orbitrap-MS was used to analyze the prototype components and metabolites in each biological sample. The results showed that 5 prototype components and 8 metabolites of Shuganning Injection and Scutellariae Radix extract were identified in liver microsomes. A total of 5 prototype components were identified in rat urine, feces, and bile separately. Fifteen metabolites were identified in the urine, 9 metabolites in the feces, and 12 metabolites in the bile. The differences of metabolic pathways and number of metabolites of baicalin were compared between Shuganning Injection and Scutellariae Radix extract. For both Shuganning Injection and Scutellariae Radix extract, the metabolites of baicalin or baicalein in rat liver microsomes, urine, bile, and feces were mainly formed glucuronic acid conjugates, and there were a small amount of glucose conjugates and methylation products. Differences were found in the number and types of metabolites of baicalin in urine samples between Shuganning Injection and Scutellariae Radix extract, indicating that differences existed in metabolism between the two. This suggests that the other components in the formula lead to changes of metabolites in vivo.
Keywords: Scutellariae Radix extract; Shuganning Injection; UPLC-Q-Exactive Orbitrap-MS; Yinchenhao Decoction; bile; feces; liver microsomes; urine.