HPLC/Q-TOF-MS-Based Identification of Absorbed Constituents and Their Metabolites in Rat Serum and Urine after Oral Administration ofCistanche deserticolaExtract

As a famous health food in China, Cistanche deserticola (C. deserticola) suggested an estrogenic activity according to our previous study. However, no one clarifies its active material basis to date. To find more potentially active constituents and elucidate metabolic pathways of metabolites, a method to simultaneously analyze multiple absorbed constituents and metabolites from C. deserticola in rat serum and urine was established using high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF-MS). Based on HPLC/Q-TOF-MS method, a total of 24 components, involving 9 prototype constituents and 15 metabolites in rat serum and urine samples, were tentatively identified based on retention time, ultraviolet spectrum, MS data, compound fragmentation laws, published literatures, and reference substances. Most of the compounds existed in the form of metabolites. The proposed metabolic pathways of main metabolites were discussed, including methylation, demethylation, hydrolysis, hydroxylation, acetoxylation, glucuronidation, dehydrogenation, sulfation, esterification, and so on. Phenylethanoid glycosides were extensively metabolized and mutually transformed in vivo. This investigation provided valuable information for further study of the active ingredients and action mechanism of C. deserticola.