In vitro absorption mechanism of Erigeron breviscapus extract in Caco-2 cell monolayer model / 中国药理学通报

Aim To study the absorption mechanism of apigenin-7-O-glucronide, 3,4-Dihydroxycinnamic acid and chlorogenic acid in Erigeron breviscapus extract ( Ebe) by Caco-2 cell monolayer model. Methods The three active ingredients were quantified by UPLC-MS/MS method, and the effect of Ebe concentrations, conveying times, pH values and P-glycoprotein inhibi-tor on the transport of three active ingredients were also investigated. Results Apigenin-7-O-glucronide and chlorogenic acid in Caco-2 cell monolayer model were time-dependent and concentration-dependent. The 3, 4-Dihydroxycinnamic acid in Caco-2 cell uptake was concentration-saturate and P-glycoprotein inhibitor was involved in the uptake process. Conclusion The mechanism of apigenin-7-O-glucronide and chlorogenic acid absorption in cells is mainly through passive trans-port, and the absorption of 3, 4-Dihydroxycinnamic acid is mainly realized by the carrier transport.

Effects of HZ08,a novel P-glycoprotein inhibitor, on the reversal of P-glyco-protein mediated multidrug resistance in nude mice and cytochrome P-450 ac-tivities in rat liver microsomes / 中国药科大学学报

Aim: To evaluate the effects of HZ08, a novel P-glycoprotein inhibitor, on reversing tumor resistance of K562/ADM to adriamycin in nude mice and on the activities of cytochromes P-450 (GYP) isoforms. Methods: Nude mice bearing K562/ADM were injected at different doses of HZ08 with adriamycin for 4 weeks. The tumor weights of HZ08 treatment groups were determined and compared to those of the control and positive groups. In addition, the effects of HZ08 were examined on GYP isoforms-mediated metabolism of specific substrates by GYP isoforms in rat liver microsomes in the presence or absence of HZ08. Results: The tumor weights of HZ08 treatment groups were significantly decreased and HZ08 was a relatively potent inhibitor of CYP3A4, with no significant effects on other isoforms tested. Conclusion: HZ08 has potent effects on reversing P-glycoprotein mediated tumor multidrug resistance in rive with little influence on cytoehrome P-450 activities of rat liver.

Progress in the research of P-gp inhibitors / 中国临床药理学与治疗学

Multidrug resistance (MDR) is one of the major obstacles to cancer chemotherapy. It is now well established that MDR phenotype is strongly correlated with the over expression of P glycoprotein (P gp), a membrane glycoprotein encoded by MDR1 gene. There is very great progress in the research of the P gp inhibitors in recent years. This article describes the current research state of the P gp inhibitors.