Absorption of panax notoginseng saponins in rat everted gut sac and interaction between it and P-glycoprotein

Objective To study the absorption characteristics of effective components of panax notoginseng saponins(PNS) including ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 in rat model of everted gut sac and interaction between PNS and P-glycoprotein(P-gp).Methods A quantitative determination was established for detecting ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 by using HPLC.The influences of different time points,concentration and transport directions on the absorption and transportation of ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 in rat small intestine by applying rat model of everted gut sac.The changes of absorptive amount of ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 were observed before and after combined use of PNS effective components and verapail(Ver),an inhibitor of P-gp.The blank group,Ver positive control group(Ver group),high-dose,mid-dose and low-dose effective components of PNS group(high-dose PNS group,mid-dose PNS group and low-dose PNS group) were set up,and the influence of effective components of PNS on the transportation of Rho123(substrate of P-gp) was observed.Results The absorption and transportation of ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 in rat small intestine were all linear absorption in different time points and concentration and all regression coefficients(r) were over 0.9,which accorded with grade 0 absorption rate.The absorption and transportation of PNS effective components were significantly influenced by transport directions,and the transport amount from serosal surface to mucosal surface(B-A) was much higher than that from mucosal surface to serosal surface(A-B).After PNS effective components combined with Ver,the absorption amount of ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 in rat small intestine increased significantly(P0.05).PNS effective components promoted the transport amount of Rho123 and it was significantly different compared with the blank group(P0.05).This efficiency was especially significant in the high-dose PNS group and the difference was greatly significant compared with Ver group(P0.01).Conclusio n The absorption and transportation of PNS effective components-ginsenoside Rg1,ginsenoside Rb1 and notoginsenoside R1 in rat small intestine are all linear absorption,so the absorption mechanism can be thought as passive transport mechanism with obvious feature of P-gp substrate transportation and inhibition of P-gp substrate exocytosis.