ABSTRACT
OBJECTIVE： To optimize the extraction technology of the flavonoids from Glycyrrhiza uralensis. METHODS： Using total contents of four flavonoids， liquiritinapioside， glycyrrhizin， isoliquiritin apioside and formononetin as indexes， types and volume fractions of extraction solvents （water， ethanol）， volume of addition and extraction time as factors， based on single factor experiment， Box-Behnken design-response surface method was used to optimize the extraction technology of flavonoids from G. uralensis. Validation test was also conducted. RESULTS： The optimal extraction technology was 50 mL 50％ ethanol as extraction solvent， 0.200 g G. uralensis， ultrasonic extraction for 50 min. In validation test， the extraction amounts of liquiritinapioside， glycyrrhizin， isoliquiritin apioside and formononetin were 10.733 0， 27.784 9， 3.441 9， 0.429 1 mg/g， respectively （all RSDs＜3.0％， n＝3）. The average total extraction amount of four flavonoids was obtained was 42.388 9 mg/g， the relative error of which to predicted value （42.173 2 mg/g） was 0.52％ （n＝3）. CONCLUSIONS： The optimized extraction technology is simple， rapid and stable， and can be used for the extraction of flavonoids from G. uralensis.
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.