Identification of the Metabolites in Rat Urine after Oral Administration and Elucidation of the Metabolic Process of Naozhenning Granule Using LC-MS.

Abstract

Naozhenning (NZN) granule, a Chinese herbal formula, is widely used to treat craniocerebral trauma and promote functional recovery. In our previous study, the chemical components, as well as the serum metabolites in the male Sprague-Dawley rats of the NZN granule after oral administration were characterized. In this study, the urine metabolites in the male Sprague-Dawley rats were further investigated by ultrahigh-performance liquid chromatography-Q Exactive hybrid quadrupole-Orbitrap high-resolution accurate mass spectrometry. In order to identify the urine metabolites comprehensively, three sample preparation methods were used, including solid-phase extraction, protein precipitation method and solvent partition. Based on the accurate molecular weight and the fragmentation information from the MS spectra, a total of 76 urine metabolites were identified, which including 17 prototypes and 59 metabolites. The results showed that the detected urine metabolites were different for the different pretreatment methods, as some metabolites could only be detected in the particular pretreatment method. In addition, the metabolic processes of the components from NZN granule to the serum and urine were also elucidated and discussed. The results will provide useful information for further studying the relationship between the chemical components and pharmacological activity of NZN granule.