Abstract: AIM: To study the uptake and metabolism of ginsenoside Rg3 (Rg3) in caco-2 cells and its kinetic profiles.METHODS: Liquid chromatography mass determination (HPLC-MS) was applied to determine Rg3 and its metabolite Rh2 concentrations in Caco-2 cells at different pH, temperature, concentration levels with the presence or absence of inhibitors.RESULTS: Rg3 uptake was time and concentration dependent, and its uptake rates were markedly reduced by metabolic inhibitors (sodium azide and 2, 4-dinitrophenol) and were influenced by low temperature.This indicated the absorption process was energy-dependent.Kinetic analysis showed that a non-saturable component (K_d 0.07 nmol ·h ^-1 · mg ^-1prot) and an active transport system with a K_m of 16.31 μmol·L ^-1 and a V_max of 3.32 nmol·h ^-1·mg ^-1prot were responsible for Rg3 uptake.CONCLUSION: Caco-2 cells are suitable for the study of ginsenoside absorption mechanism and intestinal metabolism of ginsenoside Rg3 was partly contributed to its low bioavailability.

Key words: Caco-2 cells, ginsenoside Rg3, uptake, metabolism, liquid chromatography mass determination