Elucidation the mechanism of the active ingredient imperatorin promoting drug absorption in cell model.

Imperatorin (IMP) is the main bioactive furanocoumarin of Angelicae dahuricae radix, which is a well-known traditional Chinese medicine. The purpose of this study was to elucidate the role of IMP in promoting absorption and the possible mechanism on the compatible drugs of Angelicae dahuricae radix. The influence of IMP on drugs' intestinal absorption was conducted by the Caco-2 cell model. The mechanism was studied by investigating the transcellular transport mode of IMP and its influence on P-glycoprotein (P-gp)-mediated efflux, protein expression of P-gp and tight junction, and cell membrane potential. The result showed IMP promoted the uptake of osthole, daidzein, ferulic acid, and puerarin and improved the transport of ferulic acid and puerarin in Caco-2 cells. The absorption-promoting mechanism of IMP might involve the reduction of the cell membrane potential, decrease of P-gp-mediated drug efflux and inhibition of the P-gp expression level in the cellular pathway, and the loosening of the tight junction protein by the downregulation of the expression levels of occludin and claudin-1 in the paracellular pathway. This study provides new insights into the understanding of the improved bioavailability of Angelicae dahuricae radix with its compatible drugs.

Comparison of intestinal absorption characteristics between rhubarb traditional Chinese medicine preparation and activity ingredients using in situ and in vitro model.

Objective: The intestinal absorption characteristics of active ingredients are very important for oral administration of traditional Chinese medicine (TCM) to achieve the desired therapeutic effect. However, a deeper understanding about active ingredients absorption characteristics is still lack. The aim of this study was to investigate the absorption properties and mechanism of rhubarb active ingredients in TCM preparation and pure form. Methods: The intestinal absorption behavior of active ingredients in Shenkang extract (SKE) and rhubarb anthraquinone ingredients (RAI) were investigated by in situ single-pass intestinal perfusion model. And the bidirectional transport characteristics of these active ingredients were assessed by in vitro Caco-2 cell monolayer model. Results: In situ experiment on Sprague-Dawley rats, the effective permeability coefficient values of aloe-emodin, emodin and chrysophanol in RAI were higher than those in SKE, and the value of rhein in RAI was lower than that in SKE. But the easily absorbed segments of intestine were consistent for all ingredients, whether in SKE or in RAI. In vitro experiment, the apparent permeability coefficient values of rhein, emodin and chrysophanol in RAI were higher than those in SKE, and this value of aloe-emodin in RAI was lower than that in SKE. But their efflux ratio (ER) values in SKE and RAI were all similar. Conclusion: Four rhubarb anthraquinone ingredients in SKE and RAI have similar absorption mechanism and different absorption behavior, and the microenvironment of the study models influenced their absorption behavior. The results may provide an aid for understanding of the absorption characteristics of the TCM active ingredients in complex environments and the complementarities of different research models.

Chloroquine and hydroxychloroquine as ACE2 blockers to inhibit viropexis of 2019-nCoV Spike pseudotyped virus.

BACKGROUND: The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019 and there is no sign that the epidemic is abating . The major issue for controlling the infectious is lacking efficient prevention and therapeutic approaches. Chloroquine (CQ) and Hydroxychloroquine (HCQ) have been reported to treat the disease, but the underlying mechanism remains controversial. PURPOSE: The objective of this study is to investigate whether CQ and HCQ could be ACE2 blockers and used to inhibit 2019-nCoV virus infection. METHODS: In our study, we used CCK-8 staining, flow cytometry and immunofluorescent staining to evaluate the toxicity and autophagy of CQ and HCQ, respectively, on ACE2 high-expressing HEK293T cells (ACE2h cells). We further analyzed the binding character of CQ and HCQ to ACE2 by molecular docking and surface plasmon resonance (SPR) assays, 2019-nCoV spike pseudotyped virus was also used to observe the viropexis effect of CQ and HCQ in ACE2h cells. RESULTS: Results showed that HCQ is slightly more toxic to ACE2h cells than CQ. Both CQ and HCQ could bind to ACE2 with KD = (7.31 ± 0.62)e-7 M and (4.82 ± 0.87)e-7 M, respectively. They exhibit equivalent suppression effect for the entrance of 2019-nCoV spike pseudotyped virus into ACE2h cells. CONCLUSIONS: CQ and HCQ both inhibit the entrance 2019-nCoV into cells by blocking the binding of the virus with ACE2. Our findings provide novel insights into the molecular mechanism of CQ and HCQ treatment effect on virus infection.