Comparative metabolites in plasma and urine of normal and type 2 diabetic rats after oral administration of the traditional Chinese scutellaria-coptis herb couple by ultra performance liquid chromatography-tandem mass spectrometry.

Scutellaria-coptis herb couple is widely used traditional Chinese medicine (TCM) in treating type 2 diabetes; however, the in vivo integrated metabolism of its main bioactive components in type 2 diabetic rats remains unknown. In this paper, ultra-performance liquid chromatography (UPLC) coupled to quadrupole time-of-flight (Q-TOF) and the MetaboLynx™ software combined with mass defect filtering (MDF) together provided unique high throughput capabilities for drug metabolism study with excellent MS mass accuracy and enhanced MS(E) data acquisition. This rapid automated analysis method was successfully applied for screening and identification of the absorbed and metabolized constituents after oral administration of scutellaria-coptis extract to rats. The results showed that a total of 14 metabolites of two parent compounds were detected and tentatively identified in vivo based on the characteristics of their protonated ions. Main parent components of scutellaria-coptis extract such as baicalin and berberine were absorbed into the blood circulation of the rats. Differences of metabolite classes were not observed between normal and type 2 diabetic rat plasma and urine samples. However, the concentrations of baicalin and methylated berberine in type 2 diabetic rat plasma were much higher than those in normal sample. While, the concentrations of these two compounds in type 2 diabetic rat urine were remarkably lower than those in normal sample. This helped maintain a high blood drug concentration which might be beneficial for the treatment of type 2 diabetes. Additionally, the developed method was simple and reliable, revealing that it could be used to rapid screen and propose the structures of active components responsible for pharmacological effects of scutellaria-coptis and to better clarify its action mechanism. This work suggests that the integrative metabolism approach makes a useful template for drug metabolism research of TCMs.