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.

Preparation process optimization of pig bone collagen peptide-calcium chelate using response surface methodology and its structural characterization and stability analysis.

In this study, alcalase and neutrase were used in combination to prepare collagen peptides with high calcium binding ability. The optimal conditions for the preparation of peptide-calcium chelate (mass ratio of peptide/calcium of 4.5:1 for 40 min at 50 °C and pH 9) were determined by response surface methodology (RSM), under which a calcium chelating rate of 78.38% was obtained. The results of Ultraviolet-Visible (UV-Vis), fluorescence and Fourier transform infrared (FT-IR) spectra synthetically indicated that calcium could be chelated by carboxyl oxygen and amino nitrogen atoms of collagen peptides, thus forming peptide-calcium chelate. The chelate was stable at various temperatures and pH values, and exhibited excellent stability in the gastrointestinal environment, which could promote calcium absorption in human gastrointestinal tract. Moreover, Caco-2 cell monolayer model was used to investigate the effect of peptide-calcium chelate on promoting calcium absorption. Results showed that peptide-calcium chelate could significantly improve calcium transport in Caco-2 cell monolayer and reverse the inhibition of calcium absorption by phosphate and phytate. The findings provide a scientific basis for developing new calcium supplements and the high-value utilization of pig bone.

[Transport mechanism of isorhapontigenin based on human intestinal Caco-2 cells].

Isorhapontigenin (ISO) is suggested to have many different kinds of pharmacology activities, such as anti-inflammatory effect, anti-oxidation effect and anti-cancer effect. This paper mainly discussed the transport mechanism of ISO in Caco-2 cell models. The concentration of ISO was determined by UPLC method with PDA detector at 310 nm, and then the apparent permeability coefficient Papp was calculated. The cytotoxic of different concentrations of ISO was investigated on Caco-2 cells to determine the concentration of drug administration. The effects of ISO concentration, time, temperature and transporter inhibitors on the transport of ISO were investigated. The test results showed that, ISO didn't have significant cytotoxicity at 10-60 µmol•L ⁻¹ in 14 hours. The transportation of ISO on Caco-2 cells was related to the concentration to a certain extent. Papp of ISO was higher than 10×10-6 cm•s ⁻¹ and ISO was absorbed easily by Caco-2 cells. The transport volume of ISO at BL side reached maximum at 3 h and was slightly decreased at 6 h. Papp (AP-BL) and Papp(BL-AP) at 4 ℃ were lower than those at 37 ℃. Papp (AP-BL) of ISO was significantly increased after adding P-gp inhibitor verapamil and Papp (BL-AP) of ISO was significantly decreased after adding MRP-2 inhibitor (probenecid or MK-571). The results suggested that transport mode of ISO was mainly passive diffusion in Caco-2 cell models, and P-gp and MRP may be involved in the transport of ISO.

Intestinal Absorption of Triterpenoids and Flavonoids from Glycyrrhizae radix et rhizoma in the Human Caco-2 Monolayer Cell Model.

Glycyrrhizae radix et rhizoma has been used as a traditional Chinese medicine for the treatment of various diseases. Triterpenoids and flavonoids from the plant have many beneficial effects and their chemical structures are modified in the gastrointestinal tract after oral administration. However, absorption of these triterpenoids and flavonoids still needs to be defined. Here, the uptake and transepithelial transport of the selected major triterpenoids, glycyrrhizin (1), glycyrrhetic acid-3-O-mono-ß-d-glucuronide (2), and glycyrrhetinic acid (3); and the selected major flavonoids, licochalcone A (4), licochalcone B (5), licochalcone C (6), echinatin (7), isoliquiritin apioside (8), liquiritigenin (9), liquiritin apioside (10) isolated from Glycyrrhizae radix et rhizoma, were investigated in the human intestinal epithelium-like Caco-2 cell monolayer model. Compounds 3, 5-7, and 9 were designated as well-absorbed compounds, 2 and 4 were designated as moderately absorbed ones, and 1, 8, and 10 were assigned for the poorly absorbed ones. The absorption mechanism of well and moderately absorbed compound was mainly passive diffusion to pass through the human intestinal Caco-2 cell monolayer. These findings provided useful information for predicting their oral bioavailability and the clinical application.

Pharmacokinetic studies of active triterpenoid saponins and the total secondary saponin from Anemone raddeana Regel.

The rhizome of Anemone raddeana Regel, a Traditional Chinese Medicine (TCM) which has a robust history treating rheumatism and neuralgia. The total secondary saponin (TSS) from it has demonstrated antitumor activity. In this study, a rapid and validated LC-MS/MS method was developed to simultaneously determine the active compounds (Hederacolchiside A1 and Eleutheroside K). Analytes were separated on a reverse-phase C18 column with acetonitrile-water (5mmol/L ammonium acetate) as the mobile phase. This assay showed acceptable linearity (r>0.99) over the concentration range 5-1000 nmol/L for two analytes. The intra- and inter-day precision was within 8.06% and accuracy was ranged from -3.16% to 3.34% for two analytes. The mean extraction recoveries of analytes and IS from rat plasma were all more than 76.0%. Under the developed analytical conditions, the obtained values of main pharmacokinetic parameters (Cmax and AUC0-t) indicated that the pure compounds were more efficient than the TSS extract in Hederacolchiside A1 and Eleutheroside K absorption. In addition, pharmacokinetic studies of two individual compounds demonstrated their poor oral absorption in rat (aF%, 0.019-1.521). In the study of absorption and transportation of Hederacolchiside A1 and Eleutheroside K in Caco-2 cell monolayer model, the uptake permeability was in 10-6cm/sec range suggesting poor absorption, which confirmed the previous pharmacokinetic profiles in vivo. Interestingly, the uptake ratio of them declined significantly when treated with phloridzin (SGLT1 inhibitor). It indicated that the absorption of Hederacolchiside A1 in intestine was mainly through positive transport and SGLT1 might participate in its active absorption.

Transport mechanism of isorhapontigenin based on human intestinal Caco-2 cells / 中国中药杂志

Isorhapontigenin (ISO) is suggested to have many different kinds of pharmacology activities, such as anti-inflammatory effect, anti-oxidation effect and anti-cancer effect. This paper mainly discussed the transport mechanism of ISO in Caco-2 cell models. The concentration of ISO was determined by UPLC method with PDA detector at 310 nm, and then the apparent permeability coefficient Papp was calculated. The cytotoxic of different concentrations of ISO was investigated on Caco-2 cells to determine the concentration of drug administration. The effects of ISO concentration, time, temperature and transporter inhibitors on the transport of ISO were investigated. The test results showed that, ISO didn't have significant cytotoxicity at 10-60 μmol•L ⁻¹ in 14 hours. The transportation of ISO on Caco-2 cells was related to the concentration to a certain extent. Papp of ISO was higher than 10×10-6 cm•s ⁻¹ and ISO was absorbed easily by Caco-2 cells. The transport volume of ISO at BL side reached maximum at 3 h and was slightly decreased at 6 h. Papp (AP-BL) and Papp(BL-AP) at 4 ℃ were lower than those at 37 ℃. Papp (AP-BL) of ISO was significantly increased after adding P-gp inhibitor verapamil and Papp (BL-AP) of ISO was significantly decreased after adding MRP-2 inhibitor (probenecid or MK-571). The results suggested that transport mode of ISO was mainly passive diffusion in Caco-2 cell models, and P-gp and MRP may be involved in the transport of ISO.

Promotion of suet oil to absorption and transportation of total flavonoids from Epimedii Folium / 中草药

Objective: To study the promotion mechanism of suet oil to the intestinal absorption of the total flavonoids from Epimedii Folium (EF). Methods: The in vivo intestinal perfusion model and Caco-2 cell monolayer model of rats were used to study the influence of processing excipient suet oil in self-assembled micelles on the intestinal absorption of total flavones from EF. Results: In the in vivo intestinal perfusion model of rats, there were differences of absorption of icariin in the total flavonoids from EF in the four segments of the intestines. After the suet oil was added and self-assembled micelles were formed, the permeabilities of icariin in the total flavonoids from EF were increased significantly in duodenum and jejunum segments. In Caco-2 cell monolayer model of rats, the absorptive permeability coefficients were small for icariin in the total flavonoids from EF, after the suet oil was added and the self-assembled micelles were formed, the absorptive permeability coefficients were increased significantly, the efflux ratios were decreased from 4.72 to 2.31. Conclusion: The total flavonoids from EF have a bad intestinal absorption, after the suet oil added and the self-assembled micelles formed, the intestinal absorption of the total flavonoids from EF could be improved.

Absorption properties and mechanism of trolline and veratric acid and their implication to an evaluation of the effective components of the flowers of Trollius chinensis.

AIM: To study the absorption properties and mechanism of two important components, trolline and veratric acid, from the flowers of Trollius chinensis, in order to better understand the contribution of these two compounds to the effectiveness of these flowers. METHOD: The human Caco-2 cell monolayer model was employed to study the transport of trolline and veratric acid from apical side (AP) to basal side (BL), and from BL to AP by determining the transport rates as the function of time and concentration and calculating apparent permeability coefficients (Papp). RESULTS: Trolline and veratric acid were transported across Caco-2 cell monolayer through different mechanisms in a concentration dependent manner. Trolline was transported at a Papp level of 10(-6) cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of more than 1.8 or less than 0.8, while veratric acid was transported at a Papp level of 10(-5)cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of close to 1.0. CONCLUSION: Trolline is moderately absorbed through an associative mechanism involving active and passive transport, and veratric acid is well-absorbed mainly through passive diffusion. These factors should be taken into account when chemically assessing the pharmacodynamic material basis of the flowers of T. chinensis.

Absorption properties and mechanism of trolline and veratric acid and their implication to an evaluation of the effective components of the flowers of Trollius chinensis / 中国天然药物

AIM@#To study the absorption properties and mechanism of two important components, trolline and veratric acid, from the flowers of Trollius chinensis, in order to better understand the contribution of these two compounds to the effectiveness of these flowers.@*METHOD@#The human Caco-2 cell monolayer model was employed to study the transport of trolline and veratric acid from apical side (AP) to basal side (BL), and from BL to AP by determining the transport rates as the function of time and concentration and calculating apparent permeability coefficients (Papp).@*RESULTS@#Trolline and veratric acid were transported across Caco-2 cell monolayer through different mechanisms in a concentration dependent manner. Trolline was transported at a Papp level of 10(-6) cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of more than 1.8 or less than 0.8, while veratric acid was transported at a Papp level of 10(-5)cm·s(-1) with a Papp AP→BL/Papp BL→AP ratio of close to 1.0.@*CONCLUSION@#Trolline is moderately absorbed through an associative mechanism involving active and passive transport, and veratric acid is well-absorbed mainly through passive diffusion. These factors should be taken into account when chemically assessing the pharmacodynamic material basis of the flowers of T. chinensis.

Transport characteristics of hydroxysafflor yellow A across Caco-2 cell monolayer model / 中草药

Objective: To investigate the transport characteristics of hydroxysafflor yellow A (HSYA) in Danhong Injection across Caco-2 cell monolayer. Methods: Safe concentration range of HSYA against Caco-2 cell monolayer model was selected by MTT method; The effects of time, drug concentration, temperature, pH, P-gp inhibitor (Verapamil), and energy metabolism inhibitor (sodium azide) on the absorption of HSYA were observed by Caco-2 cell monolayer model; The multidrug resistance (MDR1) gene expression in Caco-2 cells was analyzed by the RT-PCR method. Results: The Papp of HSYA transport from apical (AP) side to basolateral (BL) side was in 2 × 10-6-5 × 10-6 cm/s, which showed a medium absorption. The transport of HSYA was positively correlated with time and concentration. The Papp of HSYA transport at 37°C has significant differences with those at 4 and 25°C (P < 0.01). The Papp of HSYA transport under pH 9.0 has significant differences with those under pH 5.0 and 7.4 (P < 0.01). The gene expression of MDR1 was significantly reduced by Verapamil, but the transport of HSYA was not influenced by Verapamil and sodium azide, the number of Papp(BL→AP)/Papp(AP→BL) was between 1 and 1.5, so the absorption of HSYA was basically in line with the passive diffusion. Conclusion: The transport of HSYA across Caco-2 cell monolayer model is passive diffusion, and is not influenced by the change of P-gp and energy metabolism. Low temperature and alkaline environment are not conducive to the absorption of HSYA.

Transport characteristics of ligustrazine across Caco-2 cell monolayer model and its effect on P-glycoprotein expression / 中草药

Objective: To investigate the transport characteristics of ligustrazine across Caco-2 cell monolayer and the effect on P-glycoprotein (P-gp) expression. Methods: Safe concentration range of ligustrazine against Caco-2 cell monolayer model was selected by the MTT method. The mechanism of ligustrazine bidirectional transport was investigated by Caco-2 cell monolayer model. The influences of time, concentration, and P-gp inhibitor Verapamil on the transport of ligustrazine were studied using apparent permeability coefficient (Papp) as index. P-gp expression in Caco-2 cells was analyzed by the Western blotting method. Results: The Papp of transport from apical (AP) side to basolateral (BL) side was over 10-6 cm/s, which showed a good absorption. In the Caco-2 cell model, the transport amount of ligustrazine was positively correlated with time and concentration, and the transport amount from AP side to BL side was higher than that from BL to AP. The absorption of ligustrazine was not only rejected by P-gp, but also the P-gp expression was inhibited by ligustrazine. Conclusion: The transport of ligustrazine across Caco-2 cell monolayer model is deduced as passive transport, ligustrazine is rejected by P-gp, and there is an inhibition of ligustrazine on the expression of P-gp.

Absorption mechamism of dehydroandrographolide in human caco-2 cell monolayer model / 中草药

Objective: To study the absorption mechanism of dehydroandrographolide (DAL) in human Caco-2 cell monolayer model. Methods: Caco-2 cell monolayer model was applied to investigate the bidirectional transport of DAL. The effects of time, drug concentration, temperature, and P-gp inhibitor (Verapamil) on the absorption of DAL were observed. Drug concentration was measured by LC/MS/MS and the apparent permeability coefficients (Papp) were calculated. Results: With the time and concentration increasing, the bidirection transport of DAL in Caco-2 cell monolayer model was of time and concentration dependence, without saturation. And it was not influenced by the change of temperature and the presence of Verapamil. Conclusion: The absorption and transport of DAL are passive diffusion as the dominating process in Caco-2 cell monolayer model.

Transcytosis mechanism of chlorogenic acid across cell monolayer model / 中国药理学通报

Aim To investigate the transcytosis mechanism of chlorogenic acid(CGA)by using Caco-2 and MDCK(Madin Darby canine kidney) monolayers models.Method ① Caco-2 and MDCK cell models:Caco-2 cell(105 cells/cm2) and MDCK cell(5?104 cells/cm2) were inoculated in Millicell-CM culture plate inserts,and the TEER of cell monolayer were detected to make sure the models are available for experiments.② Permeating experiments: to measure the value of OD of CGA and calculate the cumulative amount.Result CGA could be Absorbed and secreted on two monolayer models.Verapamil could inhibit the secretion at lower concentration of CGA on MDCK monolayer model.P-pg could partly act on the secretion of CGA on Caco-2 and MDCK cell models.Conclusion CGA can secrete and Absorb at the same time across Caco-2 and MDCK cell monolayers,P-pg partly involving in the secretion of CGA.

Absorption and transportation of flavonoids in Herb Epimedii across Caco-2 monolayer model / 中草药

Objective To study the absorption and transportation of flavonoids in Herb Epimedii by using Caco-2 monolayer model. Methods Caco-2 cell monolayer model was used to study the bi-direction transport of icariin, epimedin A, epimedin B, epimedin C, and baohuoside Ⅰ. The concentration of the five flavonoids in cell culture medium was measured by UPLC and the apparent permeability coefficients (Papp) were calculated. Results The absorptive permeability coefficients (PAB) of icariin, epimedin A, epimedin B, epimedin C, and baohuoside Ⅰ were 5.91?10-7, 3.22?10-7, 2.76?10-7, 4.23?10-7, and 1.46?10-6 cm/s, respectively. Except baohuoside Ⅰ, the other four flavonodes had lower permeabilities, and the secretive permeabilities (PBA) of all the flavonoids were larger than their absorptive permeabilities. Among them, the PBA of baohuoside Ⅰ was 9.8 times as much as the PAB. Conclusion The results suggest that the intestinal absorption of the five flavonoids is lower, which might have efflux mechanism by transporters, and the absorption of monloglycoside (e.g. baohuoside Ⅰ) is better than that of diglycoside (e.g. icariin) and triglycoside (e.g. epimedin A, epimedin B, and epimedin C).

Absorptive Characteristics of Ginsenoside Rb_3 in Caco-2 Cell Monolayer Model / 中国药房

OBJECTIVE:To study the absorptive characteristics of ginsenoside Rb3 in Caco-2 cell monolayer model. METHO-DS:The ginsenoside Rb3 cell samples underwent high speed centrifugation, then the supernatant was collected and determined by LC-ESI-MS/MS method in which the mobile phase consisted of acetonitrile-1 mmol?L-1 ammonium formate water solution (34 ∶ 66) with ginsenoside Rg2 as internal standard, and the tandem mass spectrometry was operated in negative electrospray ionization in a multiple reaction monitoring (MRM) mode, with detection ions m/z1077.7→m/z 783.4 for ginsenoside Rb3 and m/z 783.6→m/z 475.1 for ginsenoside Rg2.The concentration of ginsenoside Rb3 across the Caco-2 cell monolayer model was determined and the apparent permeability coefficient(Papp) of ginsenoside Rb3 was calculated. RESULTS: The calibration curve for ginsenoside Rb3 was linear in the range of 50～2 000 ng?mL-1,with intra-day precision and inter-day precision at less than 15%. P(AP-BL) from apical side (AP) to basolateral side (BL) was 3.22?10-6 cm?s-1, whereas P(BL-AP) from BL to AP was 6.0?10-6 cm?s-1,and the ratio of P(BL-AP)/P(AP-BL) was 1.86.CONCLUSION:The LC-ESI/MS/MS method is simple and sensitive, and it is applicable for the study of the absorptive characteristics of ginsenoside Rb3 in Caco-2 cell monolayer model.