Effects of flavonoids from Glycyrrhizae Radix on function and expression of P-glycoprotein in Caco-2 cells / 中草药

ABSTRACT

Objective: To study the effects of the flavonoids from Glycyrrhizae Radix (FGR) on the function and expression of P-glycoprotein (P-gp) in Caco-2 cells, and to further explore the detoxification mechanisms of FGR. Methods: Flow cytometry was used to study the effects of FGR on the uptake of Rhodamine 123, which showed the toxic efflux function of P-gp; Western blotting method was used to detect the expression level of P-gp in Caco-2 cells. Results: Compared with the control group, after treated with the total flavonoids from Glycyrrhizae Radix (TFGR) at the different concentration (5, 10, 50, and 100 μg/mL) for 1 h, the uptake of Rhodamine 123 in Caco-2 cells was decreased by 61.1%, 56.3%, 49.2%, and 45.4%; liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, liquiritin apioside, and isoliquiritin apioside with the same dose significantly decreased the fluorescence intensity of Rhodamine 123 by 19.3%-37.9%. The expression levels of P-gp in Caco-2 cells were significantly increased (P < 0.01) after the co-incubation of TFGR (10-400 μg/mL) for 72 h, and liquiritin, isoliquiritin, liquiritigenin, and liquiritin apioside (5-400 μmol/L) had the similar functions, so did isoliquiritin and isoliquiritin apioside (10-400 μg/mL, P < 0.01). Conclusion: FGR could strengthen the function, up-regulate the expression of P-gp in Caco-2 cells, promote the efflux of toxic substances, and decrease the absorption of toxic substances, which could be one of the new mechanisms for Glycyrrhizae Radix detoxification.