Metabolism of ginsenosides Rk₃ and Rh₄ from steamed notoginseng in zebrafish by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Abstract

In this work, the metabolite profiles of ginsenosides Rk₃ and Rh₄ from steamed notoginseng in zebrafish were qualitatively investigated, and their possible metabolic pathways were subsequently proposed. Metabolites of ginsenosides Rk₃ and Rh₄ after exposing to zebrafish for 24 h were identified by Ultraperformance Liquid Chromatography/Quadrupole -Time-of-Flight Mass Spectrometry (UPLC-TOF/MS). The separation was performed with a UPLC BEH C₁₈ column using a binary gradient elution of 0.1 % formic acetonitrile −0.1 % formic acid water. The quasi-molecular ions of compounds were detected in negative mode. According to the quasi-molecular ions and MS2 spectra, after comparison with reference standards, molecular mass information and the potential structures about metabolites of ginsenosides Rk₃ and Rh₄ were obtained. In all, 5 and 6 metabolites of ginsenoside Rk₃ and Rh₄ including M1(M6), M2(M7), M3–M5 and N1, N2(N7), N3–N6 were identified in zebrafish respectively, which were to our knowledge reported for the first time. The results indicated that ginsenosides Rk₃ and Rh₄ were metabolized via desugarization, glucuronidation, sulfation, dehydroxylation, and loss of C-17 and C-23 residue pathways in zebrafish. Loss of glucose at position C-6 and glucuronidation at position C-3 or C-6 in zebrafish were considered as the main physiologic processes of ginsenosides Rk₃ and Rh₄.