RESUMEN
OBJECTIVE To explore the intestinal absorption characteristics of saikosaponins. METHODS Based on everted intestinal sac model， using accumulative absorption amount （Q） and absorption rate constant （Ka） as indexes， UHPLC-MS/MS technique as a method， the absorption of saikosaponin A， B2， C， D and F from total saponins of Bupleurum chinense （8 g/mL， by crude drug） in the duodenum， jejunum and ileum was detected. RESULTS The correlation coefficients （r） of the regression equations for the absorption of saikosaponins A， B2， C and F in the duodenum， jejunum and ileum were all higher than 0.95， while the r of saikosaponin D in the above intestinal segments was lower than 0.95； compared with the absorption of the same composition in the duodenum， the Q and Ka of saikosaponin A and C circulating in jejunum and ileum for 120 min， as well as the Q and Ka of saikosaponin F circulating in the ileum for 120 min were significantly decreased （P＜0.05）. CONCLUSIONS Saikosaponin A and the other 4 saikosaponins are all absorbed in the duodenum， jejunum and ileum； among them， saikosaponin A， B2， C and F are linearly absorbed， which conforms to the zero-order absorption characteristics， but saikosaponin D shows non- linear absorption.