Biotransformation of Ginsenosides (Rb1, Rb2, Rb3, Rc) in Human Intestinal Bacteria and Its Effect on Intestinal Flora

Ginsenosides, including Rb₁, Rb₂, Rb₃ and Rc, belong to protopanaxadiol-type saponins in Panax ginseng C. A. Mey. Their contents are high in P. ginseng. They could inhibit oxidant stress, enhance immunity, lower blood sugar, resist tumor cells and facilitate other physiological activities. This study aimed to explore the interaction between ginsenosides Rb₁, Rb₂, Rb₃ and Rc and the intestinal flora of healthy people. It also sought to analyse the biotransformation products and pathways of these ginsenosides in in-vitro human intestinal bacteria and their effects on the diversity of human intestinal flora. Human intestinal bacteria were incubated with ginsenosides Rb₁, Rb₂, Rb₃ and Rc at 37 °C under anaerobic conditions. Samples were taken at different timepoints. The transformed products were identified by rapid high-resolution liquid chromatography-quadrupole time-of-flight mass spectrometry. After 48 h of transformation, the transformed product of ginsenosides Rb₁, Rb₂, Rb₃ and Rc was ginsenoside compound K. The transformation rates were 83.5 %, 88.7 %, 85.6 %, and 84.2 %. 16S rRNA sequencing technology was applied to the bioinformatic analysis of faecal samples incubated for 48 h. Relative to the blank control, the relative abundance of Firmicutes and Proteobacteria significantly increased at the phylum level. Moreover, the relative abundance of Bacteroidetes significantly decreased in ginsenosides Rb₁, Rb₂, Rb₃ and Rc. At the genus level, the relative abundance of Escherichia significantly increased, whereas that of Dorea, Prevotella and Megasphaera significantly decreased in all groups. These results showed that Rb₁, Rb₂, Rb₃ and Rc could improve the structure and diversity of human intestinal flora and balance the metabolic process.