Study on intestinal transport of Veratrum alkaloids compatible with Panax ginseng across the Caco-2 cell monolayer model by UPLC-ESI-MS method

The Caco-2 cells have been recognized as effective tools to be applied to imitate the drug absorption in human intestine for the transport of drug. In this study, Caco-2 cell monolayer model was used to study compatibility of the transport of the Veratrum alkaloids in different proportions with Panax ginseng. A specific ultra-high performance liquid chromatographic-electrospray ionization-mass spectrometric（UPLC-ESI-MS） method is developed for the semi-quantitative determination of Veratrum alkaloids on intestinal transport with berberine as internal standard（IS）. In the Caco-2 model constructed, three influencing factors are investigated, including time, concentration and recovery rates of the Veratrum alkaloids during the uptake from AP（apical side） to BL（basolateral side）. The results suggest that the flux of Veratrum alkaloids is time dependent and concentration dependent. And the absorption of all eight Veratrum alkaloids increase after compatibility with Panax ginseng compared to the single Veratrum nigrum extraction. This research was studied from the perspective of intestinal absorption by the UPLCESI-MS method. This method was successfully applied to transport studies of the Veratrum alkaloids and the interaction mechanism between Veratrum nigrum and Panax ginseng.

Studies on Intestinal Transport of Ginsenoside Compatibility with Veratrum nigrum via Caco-2 Cell Monolayer Model Coupled with UPLC-ESI-MS Method

The Caco-2 cells have been recognized as effective tools to be applied to imitating the drug absorption in human intestine for the transport of drug. Herein, Caco-2 cell monolayer model was used to study the transport of the ginsenoside compatibility with Veratrum nigrum in different proportions. A specific high performance liquid chro- matography-electrospray ionization-mass spectrometry（HPLC-ESI-MS） method was developed for the semiquantita- tive determination of ginsenoside in intestinal transport with Dioscin as an internal standard. For the Caco-2 model constructed, two influencing factors were investigated, including time and concentration. The results suggest that the absorption of ginsenoside Re, Rgl, Rbl, Rc, Rb2 and Rd are time- and concentration-dependent and the excretions of Rbl, Rc, Rb2 and Rd have a relatronship with some transport proteins. The bioavailability of the ginsenosides has reduced compared to the single Panax ginseng extract when compatibility with a certain amount of Veratrum nigrum.

黄芩总黄酮在Caco-2细胞上的吸收特征

目的建立同时测定Caco-2细胞模型中黄芩苷、汉黄芩苷、汉黄芩素和千层纸素A的HPLC法,探讨黄芩总黄酮在Caco-2细胞上的吸收机制。方法利用人源结肠腺癌细胞系Caco-2细胞单层模型研究黄芩苷、汉黄芩苷、汉黄芩素和千层纸素A由肠腔侧(AP侧)到基底侧(BL侧)和BL侧到AP侧两个方向的转运过程。应用HPLC-UV对上述4个黄酮成分进行分析,计算转运参数和表观渗透系数(Papp)。结果黄芩总黄酮给药后,黄芩苷、汉黄芩苷、汉黄芩素和千层纸素A由AP→BL侧的Papp分别为(1.65±0.38)×10-6、(1.58±0.21)×10-6、(1.57±0.15)×10-6和(5.74±0.18)×10-6cm/s,由BL→AP侧的Papp分别为(1.23±0.24)×10-6、(1.22±0.16)×10-6、(1.27±0.07)和(5.13±0.19)×10-6cm/s;表观渗透率(PDR)分别为0.75、0.77、0.80和0.89。结论 4个黄酮类主要以被动吸收方式进入体内。

HPLC-MS analysis of Schisandra lignans and their metabolites in Caco-2 cell monolayer and rat everted gut sac models and in rat plasma

The absorption profiles of Schisandra chinensis were evaluated using the human Caco-2 cell monolayer and rat everted gut sac models,as well as in rat plasma.By analyzing the chromatographic and MSn characteristics of individual peak acquired by HPLC-DAD-APCI-MS^(n) determination,thirteen lignans were identified as the major in vitro absorbable components of the Schisandra extract.Most of these compounds were also detected and identified in rat plasma after an oral administration of the Schisandra extract,except for angeloyl(tigloyl)gomisin H and angeloyl(tigloyl)gomisin Q,whose structures possess an ester group at the cyclooctadiene ring.In addition,four metabolites,corresponding to the hydroxylation and demethylation products of schisandrin and the hydrolysis derivative of angeloyl(tigloyl)gomisin Q,were tentatively identified.The results demonstrate that Schisandra lignans are the major absorbable components of this crude drug,and hydroxylation,demethylation and hydrolysis are important metabolic transformations of the absorbable lignans.

Mechanistic studies of the transport of peimine in the Caco-2 cell model

Fritillaria thunbergii Miq. has been widely used in traditional Chinese medicine for its expectorant, antitussive, antiinflammatory and analgesic properties. Moreover, modern pharmacological studies have demonstrated that F. thunbergii Miq. has efficacy in the treatment of leukemia and cancers of the liver and cervix. Although the alkaloid, peimine, is largely responsible for these pharmacological effects, it has very low oral bioavailability. The aim of this study was to investigate the intestinal absorption of peimine in Caco-2 cell monolayers. Having demonstrated that peimine is non-toxic to Caco-2 cells at concentrations o200 μmol/L, the effect of peimine concentration, p H, temperature, efflux transport protein inhibitors and EDTA-Na_2 on peimine transport were studied. The results show that peimine transport is concentration-dependent; that at p H 6.0 and 7.4, the P_(app(AP-BL))of peimine is not significantly different but the Papp(BL-AP)) is; that both Papp(AP-BL)and P_(app(BL-AP))at 4 1C are significantly higher than their corresponding values at 37 1C; that the P-glycoprotein(P-gp) inhibitors, verapamil and cyclosporin A, increase absorption of peimine; and that EDTA-Na2 has no discernible effect. In summary,the results demonstrate that the intestinal absorption of peimine across Caco-2 cell monolayers involves active transport and that peimine is a substrate of P-gp.

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 aloeemodin, 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.

Intestinal Transport and Biotransformation of Resibufogenin and Cinobufagin in Chan Su via HPLC/APCI-MS^n

In vitro models of human colon carcinoma cell line(Caco-2 cell monolayer) and human intestinal bacteria were used to investigate the intestinal transport and biotransformation of resibufogenin and cinobufagin in Chan Su by HPLC/APCI-MSn. The experimental results of Caco-2 cell monolayer demonstrate that the apparent permeability coefficients(Papp) of resibufogenin and cinobufagin are higher than 10–6 cm/s, which indicates that both resibufogenin and cinobufagin have a good absorption in the small intestine. And the biotransformation result of human intestinal bacteria shows that resibufogenin has been transformed to 3-epiresibufogenin and cinobufagin has been transformed to 3-epicinobufagin, deacetylcinobufagin and 3-epideacetycinobufagin, respectively.

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.

3D organoids derived from the small intestine:An emerging tool for drug transport research

Small intestine in vitro models play a crucial role in drug transport research.Although conventional 2 D cell culture models,such as Caco-2 monolayer,possess many advantages,they should be interpreted with caution because they have relatively poor physiologically reproducible phenotypes and functions.With the development of 3 D culture technology,pluripotent stem cells(PSCs)and adult somatic stem cells(ASCs)show remarkable self-organization characteristics,which leads to the development of intestinal organoids.Based on previous studies,this paper reviews the application of intestinal 3 D organoids in drug transport mediated by P-glycoprotein(P-gp),breast cancer resistance protein(BCRP)and multidrug resistance protein 2(MRP2).The advantages and limitations of this model are also discussed.Although there are still many challenges,intestinal 3 D organoid model has the potential to be an excellent tool for drug transport research.