ABSTRACT
Praeruptorin A and praeruptorin C, racemic to each other, are main bioactive constituents of the species Peucedanum praeruptorum, traditionally used as a Chinese herbal medicine (also known as Bai-Hua Qian Hu). In the present study, the ability of praeruptorins A and C to activate the constitutive androstane receptor and induce human multidrug resistance-associated protein 2 expressions in HepG2 cells was investigated. The changes in mRNA level, protein expression, and transport activity of multidrug resistance-associated protein 2 were determined by quantitative real-time PCR, Western blot, and the CDF uptake assay, respectively. The effects of constitutive androstane receptor knockdown on multidrug resistance-associated protein 2 mRNA and protein expression were also measured by transient transfection of a specific constitutive androstane receptor siRNA. The results showed that praeruptorin A and praeruptorin C significantly induced the multidrug resistance-associated protein 2 mRNA and protein expression, and enhanced the transport activity of multidrug resistance-associated protein 2. A further study showed that mRNA and protein upregulation were attenuated by transient transfection of a specific constitutive androstane receptor siRNA, suggesting that the upregulation of multidrug resistance-associated protein 2 was mediated by the constitutive androstane receptor. Taken together, our findings indicate that praeruptorin A and praeruptorin C can significantly upregulate multidrug resistance-associated protein 2 expression via the constitutive androstane receptor-mediated pathway in vitro, and this should be taken as an herb-drug interaction.
Subject(s)
Apiaceae/chemistry , Coumarins/pharmacology , Drugs, Chinese Herbal/pharmacology , Herb-Drug Interactions , Multidrug Resistance-Associated Proteins/metabolism , Receptors, Cytoplasmic and Nuclear/metabolism , Constitutive Androstane Receptor , Coumarins/isolation & purification , Hep G2 Cells , Humans , Multidrug Resistance-Associated Protein 2 , Multidrug Resistance-Associated Proteins/genetics , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Transfection , Up-RegulationABSTRACT
This study is purposed to investigate the effects of praeruptorin A (PA) and praeruptorin C (PC) on UGT1A1 in HepG2 cells through hCAR pathway. PA and PC were incubated with HepG2 cells for 24 h and 48 h, mRNA and protein expressions of UGT1A1 were determined by real-time PCR and Western blotting assays. Additionally, effects of PA and PC on UGT1A1 mRNA and protein expressions were also measured after transient transfection of a specific CAR siRNA for 72 h in HepG2 cells. UGT1A1 mRNA and protein expression levels were significantly increased by PA and PC after incubation for 48 h. Moreover, the mRNA and protein up-regulations of UGT1A1 were attenuated by transient transfection of a specific CAR siRNA, suggesting the induction was mediated by CAR. The results suggest that PA and PC can significantly up-regulate UGT1A1 expression partially via the CAR-mediated pathway.