Abstract
Background: Previous studies have shown that Malus hupehensis (Pamp.) Rehd. extracts have anti-oxidant, anti-aging and other effects, its bioavailability is low, however its absorption mechanism is still unclear. To investigate the absorption properties of hyperin, quercitrin, phloridzin, quercetin, and phloretin in total flavonoids of Malus hupehensis (Pamp.) Rehd. Extracts. Methods: In situ single-pass intestinal perfusion model and in vitro Caco-2 cell model were used in this study. The effects of concentration of the extract, administration time, temperature, different intestinal segments, paracellular pathway were analyzed, and the effect of efflux inhibitors, such as the P-gp inhibitor verapamil, the multidrug resistance protein2 (MRP2) inhibitor indomethacin, the breast cancer resistance protein (BCRP) inhibitor reserpine, on the transport were evaluated. As well as EDTA, a tight junction regulator, was studied.Results: The results indicated that the jejunum was the optimal absorption intestine segment of quercitrin, phloridzin, and phloretin. And the greatest absorption intestine segment of quercetin was ileum. Furthermore, it was found that the absorption mechanisms of phloridzin in extract was involved in passive diffusion and the mediation of P-gp and MRP2 should not be neglected. The absorption mechanisms of quercetin and phloretin from extract involved active transport and were accompanied by the participation of efflux transporters, such as P-gp, MRP2 and BCRP. And also the paracellular pathway was involved in hyperin and quercitrin. Conclusion: The absorption mechanisms of five flavonoids from Malus hupehensis (Pamp.) Rehd. extract are related to the concentration of the drugs, intestinal segments, and efflux protein.
Repaglinide-loaded nanostructured lipid carriers with different particle sizes for improving oral absorption: preparation, characterization, pharmacokinetics, and in situ intestinal perfusion