Purpose: The objective of this study was to investigate the absorption behavior of total flavones of Hippophae rhamnoides L. (TFH) (the sum of isorhamnetin and quercetin as the index component) in the rat intestine using in situ circulation method.
Methods: The accumulated TFH absorption and related absorption parameters were calculated. Furthermore, the influences of Cremophor ELP and the P-glycoprotein inhibitor, verapamil, on the intestinal absorption of TFH were studied using the in situ circulation model.
Results and discussion: The results showed that the absorption of TFH increased linearly with its concentration, indicating that a passive diffusion process was dominated. There were no significant differences in the absorption of TFH in three small intestine segments of duodenum, jejunum, and ileum and at different concentrations of Cremophor ELP ranging from 0.25% to 1% (P > 0.05). With the presence of P-gp inhibitor, verapamil, in the circulation fluid, the accumulated absorption of TFH did not increase significantly (P > 0.05). Further studies on the solubility and permeability enhancement of TFH should be investigated to develop new TFH products with high bioavailability.