Metabolic Stability and Metabolite Characterization of Capilliposide B and Capilliposide C by LC⁻QTRAP⁻MS/MS

Capilliposide B (LC-B) and Capilliposide C (LC-C), two new triterpenoid saponins extracted from Lysimachia capillipes Hemsl, exhibit potential anticancer activity both in vitro and in vivo. However, their metabolic process remains unclear. In this study, the metabolic stability of LC-B, LC-C, and Capilliposide A (LC-A, a bioactive metabolite of LC-B and LC-C) was investigated in human, rat, and mouse liver microsomes, respectively. Thereafter, their metabolites were identified and characterized after oral administration in mice. As a result, species difference was found in the metabolic stability of LC-B and LC-C. All three compounds of interest were stable in human and rat liver microsomes, but LC-B and LC-C significantly degraded in mouse liver microsomes. The metabolic instability of LC-B and LC-C was mainly caused by esterolysis. Moreover, 19 metabolites were identified and characterized in mouse biological matrices. LC-B and LC-C mainly underwent deglycosylation and esterolysis, accompanied by dehydration, dehydrogenation, and hydroxylation as minor metabolic reactions. Finally, the metabolic pathway of LC-B and LC-C in mice was proposed. Our results updated the preclinical metabolism and disposition process of LC-B and LC-C, which provided additional information for better understanding efficacy and safety.

Tissue distribution of capilliposide B, capilliposide C and their bioactive metabolite in mice using liquid -tandem mass spectrometry

Lysimachia capillipes Hemsl (Primulaceae), a folk medicinal plant in China, showed significant anti-tumor activities in vivo and in vitro. Capilliposide B (LC-B) and capilliposide C (LC-C) are the main bioactive components in this plant. To explore their tissue distribution, a reliable bioanalytical method for the quantification of LC-B, LC-C and their bioactive metabolite, capilliposide A (LC-A), in mouse tissues was developed and validated. In this study, the tissue distribution profiles of the three compounds were examined after intravenous administration of pure LC-B and oral administration of total saponins of L. capillipes Hemsl extract (LCE) for 10 days. Method validation was conducted over the curve range 10.0-5000 ng/mL for all three analytes in various tissue homogenates. The relative standard deviation of intra-day and inter-day precision of the QC samples was <14.7%, and the accuracy ranged from 85.9 to 114.0%. The results indicated that LC-B was rapidly and widely distributed throughout the whole body except for muscle following intravenous administration of LC-B. In addition, LC-A was only in liver, intestine, lung and stomach. After oral administration of LCE, LC-B and LC-C were distributed into various tissues. The highest levels were observed in stomach and intestine.