[Multiple analysis of the difference in intestinal absorption between the main components and the extract of...

The aim of this study is to investigate the rat intestinal absorption behavior of two main active components, liquiritin, glycyrrhizin and the extract of Glycyrrhiza uralensis. The rat intestinal perfusion model was employed. Concentrations of the compounds of the interest in the intestinal perfusate, bile and plasma samples were determined by HPLC and UPLC. At the same time, the intestinal enzymes incubation test and the partition coefficient determination, the absorption of liquiritin and glycyrrhizin alone and the extract were multiple analyzed. The results showed that the P(eff) (effective permeability) of liquiritin or glycyrrhizin alone or the extract was less than 0.3, which suggested their poor absorption in the intestine. The P(eff) of the two main active components or the extract was not significantly different in duodenum, jejunum, colon and ileum segment. The P(eff) of the glycyrrhizin in the extract had no significant difference in the four intestinal segments compared with the glycyrrhizin alone. The absorption of the liquiritin displayed significant difference (P < 0.05) at ileum segment compared with the liquiritin alone, while it had no markedly change in the other three segments. This phenomenon indicated that some ingredients in the extract might improve the absorption of liquiritin. Moreover, no parent compounds and their metabolites were found in the intestinal perfusate, bile and the plasma samples. The results demonstrated that the influence of the other ingredients in the extract on the two components might not increase the amount of liquiritin and glycyrrhizin in the bile and plasma within the duration of the test.