To investigate the active fraction from Bletilla striata in Caco-2 cell monolayer,so as to explore its absorption mechanism of oral administration preliminarily.Active fraction from B.striata in Caco-2 cell monolayer was analyzed by UPLC-Q-TOF and detected by UPLC-MS/MS,and the effects of different concentrations,pH and P-glycoprotein inhibitors on Caco-2 cells Monolayer were investigated.Six compounds were isolated from the active fraction of B.striata in Caco-2 cell monolayer by UPLC-Q-TOF,and identified as B6,B12,B14,B17,B19 and B23,with concentration dependence.Within the 0-180 min,the uptake of B12 and B14 had a time dependence,while B6,B17,B19 and B23 tended to saturate after 60 min.All of the components had a good absorption in an acidic environment.B6 had a good absorption at pH 6.0,while the other components B12,B14,B17,B19 and B23 had a good absorption at pH4.0.The absorption of the 6 main components of B.striata were not be affected by P-glycoprotein inhibitors(verapamil/cyclosporin A).Compared with the control group,there was no difference in the absorption of B6 and B12,and the absorption of B14,B17,B19 and B23 increased,but with no significant difference.The absorption characteristic of B.striata extract across the Caco-2 cell monolayer is probably passive diffusion,and the absorption process was not affected by P-glycoprotein.
Keywords: Bletilla striata; Caco-2; P-glycoprotein; UPLC-Q-TOF; UPLC-TQD; passive diffusion.