HPLC考察白头翁汤4种标志成分在Caco-2细胞模型的转运特征

目的研究白头翁汤中标志成分秦皮甲素、秦皮乙素、小檗碱、白头翁皂苷B4在Caco-2细胞模型的转运特征及其机制。方法通过HPLC建立白头翁汤指纹图谱以及4种标志成分的同时定量分析方法,随后以Caco-2细胞模型和p-gP抑制剂维拉帕米考察复方标志成分的双向转运机制,通过HPLC检测药物浓度计算其表观渗透系数（Papp）。结果①秦皮甲素在顶端（AP）和底端（BL）双向转运大致相同,为被动转运机制;②秦皮乙素在AP侧转运大于BL侧,维拉帕米可抑制AP侧向BL侧转运,为主动转运机制;③小檗碱在AP侧和BL侧转运大致相同,对于BL-AP侧外排Papp值显著低于单体的文献报道值,在复方中可能存在化学成分抑制小檗碱BL侧向AP侧外流载体,促使外流减少,增加小檗碱的摄取;④白头翁皂苷B4紫外响应弱,未能检测出。结论白头翁汤中秦皮甲素、秦皮乙素、小檗碱可通过HPLC考察其在Caco-2细胞模型的转运特征。     

千层纸素A在Caco-2细胞模型中的吸收机制研究

目的研究千层纸素A在Caco-2细胞模型中的吸收机制。方法 MTT实验考察千层纸素A在Caco-2细胞中的安全浓度范围,再利用Caco-2细胞单层模型研究千层纸素A的双向转运机制,以转运量及表观渗透系数(Papp)为指标,考察时间、浓度、pH和P-gp抑制药维拉帕米对其吸收的影响。结果千层纸素A在Caco-2细胞模型中的转运与时间和浓度呈正相关;并受pH值影响,P-gp抑制药维拉帕米对其转运无影响,从单层细胞层顶端(AP)到基底端(BL)的转运与基底端到顶端的转运大致相同。结论千层纸素A在Caco-2细胞模型中的吸收是被动转运。     

根皮苷和3-羟基根皮苷在Caco-2细胞单层模型中的转运与吸收研究

目的:研究根皮苷和3-羟基根皮苷在人克隆结肠腺癌细胞(Caco-2细胞)单层模型中的转运与吸收。方法:采用高效液相色谱法,以表观渗透系数(Papp)为指标,分别考察50、100、200μmol/L的根皮苷和3-羟基根皮苷在Caco-2细胞单层模型中的双向(AP→BL、BL→AP)转运;并通过两药配伍同时混合转运与两药单独转运比较,考察两药转运的相互作用。结果:随着浓度的增加,根皮苷AP→BL和BL→AP的Papp均有一定的上升趋势;3-羟基根皮苷AP→BL的Papp有下降趋势,BL→AP的Papp却略有上升趋势。与单独转运比较,混合转运中根皮苷和3-羟基根皮苷的转运量和Papp均明显下降(P<0.05)。结论:根皮苷和3-羟基根皮苷在Caco-2细胞单层模型的吸收状况良好,两药配伍转运时存在竞争性抑制。     

大蒜素在Caco-2细胞模型转运特征的研究

目的研究大蒜素在Caco-2细胞的转运特征。方法应用Caco-2细胞模型考察转运时间、药物浓度时大蒜素吸收的影响,采用高效液相色谱法测定大蒜素浓度,计算其表观渗透系（Papp）。结果随着浓度增加和时间延长,大蒜素累积通透量逐渐增加;大蒜素的Papp在2个方向比值[Papp（BL→AP）,Papp（AP→BL）]为1．80,存在方向性差异。结论大蒜素的转运属于双向转运,且吸收良好。     

白花前胡丁素在人结肠腺癌细胞系细胞模型上的吸收转运特征研究

目的研究白花前胡丁素在人结肠腺癌细胞系(Caco-2)细胞模型上的转运特征。方法利用Caco-2单层细胞模型研究白花前胡丁素的双向转运,采用高效液相色谱(HPLC)法测定药物的转运量,计算其表观渗透系数(Papp),并考察时间和药物质量浓度对其转运的影响。结果白花前胡丁素在Caco-2细胞模型上的双向转运量在120min内均随时间与浓度的增加而增大,其从肠腔侧(AP)向基底侧(BL)和从BL向AP的Papp介于2.0×10-6cm/s～5.0×10-6cm/s,Papp(BL-AP)/Papp(AP-BL)<1.5。结论白花前胡丁素为吸收较差的药物,主要以被动扩散方式经肠道吸收。     

左旋紫草素肠道转运及Caco-2细胞转运特性

目的研究左旋紫草素肠道及Caco-2细胞转运特征及其机制。方法应用翻转肠囊法和Caco-2细胞模型考察时间、浓度对左旋紫草素转运吸收特性的影响,应用P-糖蛋白抑制剂维拉帕米对左旋紫草素转运吸收机制进行研究,采用HPLC法测定左旋紫草素的浓度,计算其表观渗透系数(Papp)。结果在Caco-2细胞模型,随浓度增加和时间延长,左旋紫草素的累积转运量逐渐增加;加用维拉帕米后,使AP侧到BL侧的表观渗透系数Papp(AP→BL)显著增加,而从BL侧到AP侧的表观渗透系数Papp(BL→AP)显著降低。在翻转肠囊模型,100μmol·L-1左旋紫草素中加入维拉帕米后Papp显著增加。结论左旋紫草素的转运存在被动转运和主动转运2种形式,P糖蛋白参与主动转运过程;该药经肠道吸收中等,加入维拉帕米可能促进吸收。     

黄连小檗碱对人肠癌Caco-2细胞凋亡和细胞周期的影响

目的探讨黄连小檗碱对人肠癌细胞株Caco-2细胞周期和细胞凋亡的影响及其作用机制。方法采用MTT法,检测不同时间点不同浓度黄连小檗碱对Caco-2细胞的增殖抑制作用;应用流式细胞术(Annexin V-FITC/PI双染法),检测不同浓度黄连小檗碱对Caco-2细胞周期和凋亡的影响。结果不同浓度的黄连小檗碱干预肠癌细胞Caco-2不同时间后,均具有一定的增殖抑制作用,在一定浓度范围内,可以剂量和时间依赖性的抑制Caco-2细胞增殖。黄连小檗碱干预细胞24 h后,可使Caco-2细胞停滞在G2/M期,诱导细胞凋亡(P<0.05)。结论黄连小檗碱可以显著抑制Caco-2细胞增殖,其作用机制可能与阻滞细胞周期从而诱导细胞凋亡有关。     

蜕皮甾酮在Caco-2细胞模型中的摄取和跨膜转运研究

目的以Caco-2细胞单层模型,首次研究了蜕皮甾酮的口服吸收与转运特性。方法采用普通Caco-2细胞模型、表达活性CYP3A4酶的Caco-2细胞模型,分别从AP→BL方向和BL→AP方向研究蜕皮甾酮的摄取和跨膜转运规律。结果蜕皮甾酮在2种模型中的表观渗透系数(Papp)在0.1×10-6～1×10-6cm.s-1之间,药物吸收情况为1%～10%;在4 h的实验过程中,4种浓度蜕皮甾酮的ER值均小于1.5。结论研究表明,蜕皮甾酮主要以被动扩散的方式被细胞摄取和转运,其跨膜转运特性未受到CYP3A4-介导机制的影响。     

麻黄挥发油对麻黄碱和伪麻黄碱经Caco-2细胞转运特征的影响

摘要：目的:基于"性味药理"研究思路,选取麻黄挥发油和生物碱作为其辛温解表主要功效成分,从药物吸收转运角度研究麻黄解表发散的作用原理。方法:采用Caco-2细胞转运模型,HPLC同步对比分析麻黄挥发油加入对麻黄碱和伪麻黄碱从板顶端（AP）→底端（BL）及BL→AP的双向转运过程的影响,计算表观渗透系数,并分析挥发油对其转运特征的影响。结果:麻黄碱和伪麻黄碱的Caco-2细胞表观渗透系数(Papp)与浓度无显著关系。麻黄碱的Papp（AP→BL）约为19×10-6cm·s-1,伪麻黄碱的Papp（AP→BL）约为16×10-6cm·s-1,吸收作用均较好,外排率均值为0.72,推测其转运过程主要为被动转运过程。麻黄挥发油促进麻黄碱和伪麻黄碱的转运吸收,其对伪麻黄碱促进吸收作用更为显著。结论:挥发油和生物碱在麻黄解表发散功效可能存在协同作用。     

隐丹参酮在Caco-2细胞模型中的吸收机制

目的 研究隐丹参酮在Caco-2细胞模型中的吸收机制。方法 用Caco-2细胞单层模型研究隐丹参酮的双向转运，并考察时间、药物浓度及抑制剂对隐丹参酮吸收的影响。用高效液相色谱法检测药物浓度，计算其表观渗透系数。结果 隐丹参酮在Caco-2细胞模型中，从单层细胞层顶端到基底端的转运大于基底端到顶端的转运，随时间和浓度的增加，药物吸收呈饱和趋势，且可被其结构类似物丹参酮Ⅱ。竞争性抑制。结论 隐丹参酮在Caco-2细胞模型中的吸收主要是由载体介导的主动转运，且该主动转运的载体位于Caco-2细胞单层的顶端。     

Effect of ion-pair formation with bile salts on the in vitro cellular transport of berberine

The objective of this study was to examine the effect of ion-pair complexation with endogenous bile salts on the transport of a quarternary ammonium organic cationic (OC) drug, berberine, across the Caco-2 and LLC-PK1 cell monolayers. The basolateral-to-apical (BL-AP) transport of berberine in Caco-2 cells was temperature dependent and 10-fold higher than that of the apical-to-basolateral (AP-BL) transport. Similar results were observed for the transport of berberine across the LLC-PK1 cells. Moreover, the BL-AP transport in the Caco-2 cells was significantly reduced by the cis-presence of P-glycoprotein (P-gp) inhibitors such as cyclosporine A, verapamil, and digoxin. These results suggest that an efflux transporter, probably P-gp, is involved in the Caco-2 cell transport. The K_m and V_max values for the carrier-mediated transport were estimated to be 83.4 mM and 7640 pmole/h/cm², respectively. The apparent partition coefficient (APC) of berberine between n-octanol and a phosphate buffer (pH 7.4) was increased by the presence of an organic anion (OA), taurodeoxycholate (TDC, a bile salt), suggesting the formation of a lipophilic ion-pair complex between an OC (berberine) and an OA (TDC). Despite the ion-pair complexation, however, the BL-AP transport of berberine across the Caco-2 and LLC-PK1 cells was not altered by the cis-presence of bile salts or the rat bile juice. This is consistent with the reportedly unaltered secretory transport of a quarternary ammonium compound, tributylmethylammonium (TBuMA), across the Caco-2 cell monolayers in the cis-presence of bile salts or the rat bile juice, but not with our previous report in which the secretory transport of TBuMA across the LLC-PK1 cell was increased in the cis-presence of TDC. Therefore, the effect of ion-pair formation with the bile components or bile salts on the secretory transport of OCs appears to depend on the molecular properties of OCs (e.g., molecular weight, lipophilicity and affinity to relevant transporters) and the characteristics of cell strains (e.g., expression and contribution of responsible transporters to the transport).     

P-glycoprotein-mediated transport of berberine across Caco-2 cell monolayers

The objective of this study was to investigate the mechanisms by which berberine is transported in the secretory and absorptive directions across Caco-2 cell monolayers. The basolateral-to-apical (B-A) flux was 30-fold greater than the apical-to-basolateral flux and temperature dependent (i.e., drastic decrease at 4 degrees C compared with 37 degrees C). The above results suggest the involvement of a carrier-mediated active transport mechanism for the B-A transport of berberine. However, no significant concentration dependency for the permeability (P(app)) of berberine was observed for B-A transport over a concentration range of 5-300 microM, indicating that the K(m) value of berberine for the carrier system is greater than 300 microM. Well-documented P-glycoprotein (P-gp) substrates such as verapamil, daunomycin, and rhodamine123 inhibited the B-A flux of berberine, whereas tetraethylammonium and taurocholate did not, suggesting that P-gp is involved in the transport. For the case of daunomycin, the B-A flux, but not the apical-to-basolateral flux, was significantly increased after pretreatment of the cell monolayers with berberine. In addition, the uptake of 1 microM daunomycin into Caco-2 cells was decreased as a result of this pretreatment. These results suggest that the repeated administration of berberine may up-regulate P-gp functions in Caco-2 cells. If this occurs in the gastrointestinal epithelial cells, the repeated administration of berberine may reduce the gastrointestinal absorption of P-gp substrates including chemotherapeutic agents such as daunomycin.     

The antihyperglycaemic activity of berberine arises from a decrease of glucose absorption

The mechanism of action of berberine as an antihyperglycaemic agent was investigated in the Caco-2 cell line. Berberine was found to effectively inhibit the activity of disaccharidases in Caco-2 cells. It also decreased sucrase activity after preincubation with Caco-2 cells for 72 hours. However gluconeogenesis and glucose consumption of Caco-2 cells were not influenced. 2-Deoxyglucose transporting through Caco-2 cell monolayers was decreased by berberine but the effect was not statistically significant. These results suggest that the antihyperglycaemic activity of berberine is at least partly due to its ability to inhibit alpha-glucosidase and decrease glucose transport through the intestinal epithelium.     

Intestinal absorption mechanisms of berberine, palmatine, jateorhizine, and coptisine: involvement of P-glycoprotein

The absorption and transport mechanisms of berberine, palmatine, jateorhizine, and coptisine were studied using a Caco-2 cells uptake and transport model, with the addition of cyclosporin A and verapamil as P-glycoprotein (P-gp) inhibitors and MK-571 as a multidrug resistance-associated protein 2 (MRP(2)) inhibitor. In the uptake experiment, berberine, palmatine, jateorhizine, and coptisine were all taken into Caco-2 cells, and their uptakes were increased in the presence of cyclosporin A or verapamil. In the transport experiment, P(app) (AP-BL) was between 0.1 and 1.0?×?10(6) cm/sec for berberine, palmatine, jateorhizine, and coptisine and was lower than P(app) (BL-AB). ER values were all >2. Cyclosporin A and verapamil both increased P(app) (AP-BL) but decreased P(app) (BL-AB) for berberine, palmatine, jateorhizine, and coptisine; ER values were decreased by >50%. MK-571 had no influence on the transmembrane transport of berberine, palmatine, jateorhizine, and coptisine. At a concentration of 1-100 μM, berberine, palmatine, jateorhizine, and coptisine had no significant effects on the bidirection transport of Rho123. Berberine, palmatine, jateorhizine, and coptisine were all P-gp substrates; and at the range of 1-100 μM, berberine, palmatine, jateorhizine, and coptisine had no inhibitory effects on P-gp.     

The involvement of P-glycoprotein in berberine absorption

Berberine is an important ingredient in a number of traditional Chinese medicines but has been shown to have poor bioavailability in the dog. The aim of this study was to use the P-glycoprotein (P-glycoprotein) inhibitors cyclosporin A, verapamil and the monoclonal antibody C219 in in vivo and in vitro models of intestinal absorption to determine the role of P-glycoprotein in berberine absorption. In the rat recirculating perfusion model, berberine absorption was improved 6-times by P-glycoprotein inhibitors. In the rat everted intestinal sac model, berberine serosal-to-mucosal transport was significantly decreased by cyclosporin A. In Ussing-type chambers, the rate of serosal-to-mucosal transport across rat ileum was 3-times greater than in the reverse direction and was significantly decreased by cyclosporin A. In Caco-2 cells, berberine uptake was significantly increased by P-glycoprotein inhibitors and by monoclonal antibody C219. P-glycoprotein appears to contribute to the poor intestinal absorption of berberine which suggests P-glycoprotein inhibitors could be of therapeutic value by improving its bioavailability.     

Intestinal absorption mechanisms of berberine,palmatine, jateorhizine,and coptisine: involvement of P-glycoprotein

1. The absorption and transport mechanisms of berberine, palmatine, jateorhizine, and coptisine were studied using a Caco-2 cells uptake and transport model, with the addition of cyclosporin A and verapamil as P-glycoprotein (P-gp) inhibitors and MK-571 as a multidrug resistance-associated protein 2 (MRP₂) inhibitor.

2. In the uptake experiment, berberine, palmatine, jateorhizine, and coptisine were all taken into Caco-2 cells, and their uptakes were increased in the presence of cyclosporin A or verapamil.

3. In the transport experiment, P_app (AP-BL) was between 0.1 and 1.0?×?10⁶ cm/sec for berberine, palmatine, jateorhizine, and coptisine and was lower than P_app (BL-AB). ER values were all >2. Cyclosporin A and verapamil both increased P_app (AP-BL) but decreased P_app (BL-AB) for berberine, palmatine, jateorhizine, and coptisine; ER values were decreased by >50%. MK-571 had no influence on the transmembrane transport of berberine, palmatine, jateorhizine, and coptisine.

4. At a concentration of 1–100 μM, berberine, palmatine, jateorhizine, and coptisine had no significant effects on the bidirection transport of Rho123.

5. Berberine, palmatine, jateorhizine, and coptisine were all P-gp substrates; and at the range of 1–100 μM, berberine, palmatine, jateorhizine, and coptisine had no inhibitory effects on P-gp.

     

黄连素对P-糖蛋白底物在Caco-2和L-MDR1细胞跨膜转运的影响

目的研究黄连素(berberine,Ber)对P-糖蛋白底物环孢素(cyclosporine A,CsA)和地高辛在Caco-2和L-MDR1细胞跨膜转运的影响。方法以Caco-2、L-MDR1细胞为模型,在50μmol·L-1～5mmol·L-1Ber作用后,测定地高辛和CsA跨膜转运的转运率和表观渗透系数。结果Ber在50μmol·L-1～5mmol·L-1范围内可剂量依赖性地降低地高辛在Caco-2和L-MDR1细胞单层底端(B侧)至顶端(A侧)的转运。对于CsA在Caco-2细胞的转运,50μmol·L-1～5mmol·L-1的Ber不但剂量依赖性地降低CsA从B→A方向的转运,而且也明显增加其在A→B方向的转运。在Caco-2和L-MDR1细胞,Ber抑制地高辛B→A方向转运的IC50值分别为1.44mmol·L-1和1.24mmol·L-1。Ber抑制CsA在Caco-2细胞转运的IC50值为607μmol·L-1。结论Ber和CsA相互作用的机制可能涉及P-gp功能的抑制和饱和。     

小檗碱对葡萄糖吸收的抑制作用

目的研究小檗碱的吸收特性和对肠道葡萄糖吸收的影响,探索小檗碱抗糖尿病作用机制。方法采用在体肠灌流模型观察小檗碱的吸收特性;用Caco-2细胞模型研究小檗碱对肠上皮细胞二糖酶(麦芽糖酶)活力的影响和对葡萄糖转运蛋白的作用。结果小檗碱在肠道内几乎不吸收(2.5 h吸收量小于5%),但能有效抑制小肠上皮细胞上二糖酶活力,其抑制蔗糖酶的ID50为1.830 mg·L^-1;对麦芽糖酶也有抑制作用,但无明显的剂量关系。小檗碱对于葡萄糖在Caco-2细胞上的摄取也有一定抑制作用。结论小檗碱抗糖尿病作用可能主要通过抑制蔗糖酶、麦芽糖酶等二糖酶活力,作为一种α-葡糖苷酶抑制剂发挥其抗糖尿病作用。     

Effect of the co-occurring components from green tea on the intestinal absorption and disposition of green tea polyphenols in Caco-2 monolayer model

This study aimed to investigate the effect of co-occurring components from green tea on the intestinal absorption and disposition of green tea polyphenols (GTPs) using the Caco-2 cell monolayer model. The absorption and secretion transport of the four GTPs, in the form of individual pure compounds, pure compound mixtures and green tea extract, were studied in the Caco-2 cell model. Four GTPs and their metabolites were analysed by HPLC/MS and HPLC coupled with electrochemical detector. The apparent permeability coefficients (P(app)) of each compound, as well as the metabolites (mainly sulfation and methylation conjugates) generated, were compared for the different dosing formulations utilized. The results showed that the absorption transport of the four GTPs in different dosing formulations was similar. However, the secretion transport profiles of (-)-epicatechin (EC), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) were altered when the GTP mixture was administered. It was suggested that transporter competition resulting in reduced efflux of EC, as well as metabolic competition resulting in reduced formation of EGC sulfate and methylated EGC sulfate, might be involved during the secretion transport of GTP mixture.