丹参素在Caco-2细胞单层模型中的跨膜转运研究

目的:研究丹参素在Caco-2细胞模型中的跨膜转运机制。方法:通过研究丹参素在模型中的双向转运,考察时间、药物浓度及转运蛋白抑制剂对丹参素吸收的影响。用液相-质谱联用法检测药物浓度,计算其表观渗透系数。结果:表观渗透系数P_app值随时间延长而增大,到一定时间趋向饱和状态,并随丹参素浓度的增加而逐渐减小。双向转运的P_app比值即P_ratio均大于1.5。在加入P-gp转运蛋白抑制剂维拉帕米后,丹参素P_app,A-B值显著增大,而P_app,B-A值显著降低。结论:丹参素在Caco-2细胞模型中的转运可能主要是由P-gp转运蛋白介导的主动转运。     

羟基红花黄色素A在Caco-2细胞单层模型的转运研究

目的 研究丹红注射液中主要成分羟基红花黄色素A（HSYA）在Caco-2细胞单层模型的转运特征。方法 MTT法确定HSYA对Caco-2细胞单层模型作用的安全浓度范围;采用Caco-2细胞单层模型考察转运时间、药物质量浓度、温度、pH值以及P-糖蛋白（P-gp）抑制剂维拉帕米和能量代谢抑制剂叠氮化钠对HSYA转运的影响;RT-PCR法检测HSYA及维拉帕米对多药耐药基因（MDR1）表达的影响。结果 从顶侧（AP）到底侧（BL）（AP→BL）,HSYA的表观渗透系数（P_app）在2×10^-6～5×10^{-6 cm/s},表明其吸收性中等;HSYA的转运与其质量浓度和时间呈正相关,37℃下HSYA的P_app与4、25℃下的P_app有显著差异（P<0.01）,pH值为9.0时的P_app与pH值为5.0、7.4时的P_app值也有明显差异（P<0.01）。维拉帕米能明显下调MDR1基因的表达,但HSYA的转运不受维拉帕米的影响;叠氮化钠影响细胞能量代谢,但HSYA的转运不受能量代谢异常的影响,且P_app(BL→AP)/P_app(AP→BL)在1～1.5,HSYA的吸收过程基本符合被动扩散。结论 HSYA在Caco-2细胞模型的转运方式为被动扩散,且不受P-gp和能量代谢的影响,低温和碱性环境下不利于HSYA的吸收。     

替米沙坦在Caco-2细胞模型中的体外转运研究

 目的研究替米沙坦(telmisartan,TMS)在Caco-2细胞中的跨膜转运特征。方法采用体外培养的人小肠上皮细胞Caco-2模型对TMS的跨膜转运进行研究。考察了浓度、pH、P-糖蛋白(P-glyprotein,P-gp)抑制剂对TMS跨膜转运的影响。结果TMS在Caco-2细胞中的转运存在外排作用,并且外排作用随着浓度的增加趋于饱和;另外TMS的吸收转运随pH值的增加而减少。加入P-糖蛋白抑制剂环孢素A和胺碘酮后,P_ratio从3.5分别下降到1.2和0.9,加入前后有极显著性差异(P<0.01)。结论P-gp参与了TMS的跨膜转运,从而从吸收机制上初步解释了P-gp的外排作用可能是TMS生物利用度低,个体差异大的原因。     

淫羊藿苷在Caco-2细胞单层模型中的吸收机制

目的:研究淫羊藿苷在Caco-2细胞模型中的吸收机制。方法:通过研究10,20μmol.L^-1淫羊藿苷在细胞中的双向转运,考察时间、药物浓度及转运蛋白抑制剂对淫羊藿苷吸收的影响。用超高压液相法测定药物浓度,计算其表观渗透系数。结果:淫羊藿苷通过Caco-2细胞单层的转运量4 h内随时间延长呈线性增大,双向转运的渗透系数P_BA/P_AB大于4。在加入P-糖蛋白(P-gp)转运蛋白抑制剂维拉帕米后,淫羊藿苷P_AB增大了1.2倍[(1.37±0.10)×10^-6cm.s^-1],P_BA/P_AB显著降低(由4.83下降到2.72)。而加入转运蛋白多药耐药蛋白(MRP2)的抑制剂白细胞三烯C₄、乳腺癌耐药蛋白(BCRP)的底物潘生丁时,对淫羊藿苷转运影响不显著。结论:结果提示淫羊藿苷口服吸收差的原因有二:一是淫羊藿苷肠壁的渗透系数较小,二是可能存在肠道P-gp转运蛋白对淫羊藿苷的外排。     

丹参脂溶性成分在Caco-2细胞模型中吸收机制研究

 目的研究丹参脂溶性成分在Caco-2细胞模型中的吸收机制。方法以Caco-2细胞作为吸收研究模型,分别测定了各种条件下,包括分别以单体丹参酮Ⅱ_A和丹参醇提取物给药、改变给药浓度、改变转运方向以及加入影响吸收的物质,丹参酮Ⅱ_A,隐丹参酮和丹参酮Ⅰ的转运情况。结果给予不同剂量的丹参酮ⅡA,其表观通透系数P_app随浓度的增加先降低后升高; 丹参酮Ⅱ_A细胞绒毛侧Apical→基底侧Basolateral转运(AP→BL)大于BL→AP 5倍以上;随着冰片含量增加,丹参脂溶性成分的 P_app明显增大;EDTA对吸收没有明显影响。结论丹参酮Ⅱ_A在Caco-2细胞模型中的转运机制类似载体介导转运兼有被动扩散,无细胞旁路途径,无外排泵参与;冰片有促吸收的作用。本实验结果为含丹参的制剂研究、口服给药等提供信息。     

蛇床子素在Caco-2细胞模型中的转运机制研究

 目的 研究蛇床子素在 Caco-2 细胞模型中的转运机制。方法 通过研究蛇床子素在 Caco-2 细胞模型中的转运,考察蛇床子素浓度、PEG600、P-gp抑制剂维拉帕米（verapamil及温度对蛇床子素转运的影响。结果 随着蛇床子素溶液浓度和温度的升高,蛇床子素在Caco-2 细胞中 AP-BL 的转运量增加;PEG600对蛇床子素在 Caco-2 细胞中的 AP-BL 的转运量有显著增加;P-gp 抑制剂维拉帕米对蛇床子素在 Caco-2 细胞中转运的表观通透系数 PAP 和 PBL 无显著影响。结论 蛇床子素表观通透系数 PAP大于10×10-6 cm·s-1,较易被 Caco-2 细胞吸收,但由于3个浓度蛇床子素溶液的PAP 和 PBL比值无明显变化、P-gp 抑制剂对 PAP 和 PBL 无明显影响及转运的活化能较低(17.31 kJ·mol-1,因此,蛇床子素在 Caco-2 细胞模型中的转运机制主要是被动转运。     

Caco-2细胞单层模型研究黄芩提取物中黄芩苷转运机制及白芷提取物对其转运的影响

目的: 研究黄芩提取物中黄芩苷的吸收转运机制以及白芷提取物对其吸收影响,分析探讨白芷提取物对黄芩苷转运的影响机制。 方法: 建立人源结肠腺癌细胞系 Caco-2细胞模型,利用此模型研究pH、时间、药物浓度、温度对黄芩提取物中黄芩苷的转运影响;研究黄芩苷在P-gp, MRP蛋白专属抑制剂存在与否时黄芩苷在Caco-2细胞模型的双向转运情况;并考察白芷提取物对黄芩苷吸收转运的影响。 结果: 37℃环境下黄芩苷转运在pH 7.4条件下吸收较好,且存在浓度依赖性;4℃环境下蛋白失活,转运量降低;黄芩苷双向转运PDR为0.54,P-gp抑制剂维拉帕米、MRP抑制剂丙磺舒加入后,黄芩苷BL→AP转运减少,而PDR无差异。加入白芷活性成分香豆素、挥发油、香豆素与挥发油混合物后黄芩苷转运分别提高了2.34,3.31,3.13倍。 结论: 黄芩苷主要转运机制为被动转运,兼有外排蛋白参与。白芷活性成分对黄芩苷有促吸收作用,此作用可能与黄芩苷的被动转运机制有关,白芷提取物打开了细胞间的紧密连接,也可能与白芷抑制外排蛋白的表达或功能有关。     

巴戟天中有效成分在Caco-2细胞模型中的吸收转运

目的 研究巴戟天中的有效成分水晶兰苷、去乙酰车叶草苷酸和耐斯糖在人源结肠癌细胞Caco-2单层模型中的吸收特性。方法 通过细胞培养技术建立Caco-2细胞单层模型,以细胞形态学特征、细胞跨膜电阻等指标验证和筛选模型。考察不同pH、不同质量浓度的水晶兰苷、去乙酰车叶草苷酸和耐斯糖对Caco-2细胞活力的影响,以确定给药pH和质量浓度。通过Caco-2细胞转运实验探究药物质量浓度、作用时间与P-糖蛋白抑制剂维拉帕米对水晶兰苷、去乙酰车叶草苷酸和耐斯糖吸收转运的影响。采用高效液相色谱法（HPLC）测定水晶兰苷、去乙酰车叶草苷酸和耐斯糖的累积转运量。结果 水晶兰苷、去乙酰车叶草苷酸和耐斯糖在Caco-2细胞单层模型中吸收良好,三者低质量浓度的双侧表观渗透系数（P_app）明显大于中、高质量浓度;加入盐酸维拉帕米后,三者的P_app变化不大,说明这3个成分的小肠吸收不需要载体。去乙酰车叶草苷酸的液相色谱图中存在少量水晶兰苷,说明去乙酰车叶草苷酸存在首过效应。结论 巴戟天中水晶兰苷、去乙酰车叶草苷酸和耐斯糖3个特征性成分在跨膜转运过程中均以被动转运为主,且3个成分都存在自身质量浓度抑制现象。     

Caco-2细胞单层模型中熊果酸摄取转运机制的研究

目的 研究熊果酸在Caco-2细胞单层模型中的吸收转运机制.方法 利用人源结肠腺癌细胞系Caco-2细胞单层模型研究熊果酸在有或无P-糖蛋白专属性抑制维拉帕米存在时,评价其双向转运特征,并考察时间、药物浓度、体系温度以及培养介质pH值对Caco-2细胞摄取熊果酸的影响.采用高效液相色谱-紫外检测法对熊果酸进行定量分析,计算其表现渗透系数(P_(app)).结果 浓度在10～40 μmol/L内,Caco-2细胞对熊果酸摄取量呈线性增加.双向转运研究发现加入P-糖蛋白专属性抑制剂维拉帕米后.其P_(app)发生显著改变,表观渗透率由3.445下降至1.386.结论 熊果酸在Caco-2细胞模型的吸收转运机制以被动转运为主,P-糖蛋白参与主动转运的过程.     

Caco-2细胞模型研究川芎提取物中阿魏酸转运机制及白芷提取物对其转运的影响

目的:利用人源结肠腺癌细胞系Caco-2细胞单层模型,研究了川芎提取物中阿魏酸的吸收转运机制,以及白芷提取物对其吸收转运的影响。方法:建立人源结肠腺癌细胞系Caco-2细胞模型,利用此模型研究时间、药物浓度对川芎提取物中阿魏酸的转运影响与阿魏酸的双向转运特征;研究川芎中阿魏酸在有或无P-gp、MRP蛋白专属抑制剂存在时阿魏酸在Caco-2细胞模型的双向转运情况;并考察白芷提取物对川芎中阿魏酸吸收转运的影响。结果:阿魏酸在3h范围内转运速率保持恒定,在浓度范围(28～336mg/ml)内浓度与转运速率呈线性相关;加入P-gp和MRP蛋白抑制剂后,阿魏酸的AP侧转运增加,BL侧转运降低,PDR值下降;加入白芷有效成分(香豆素:0.45mg/ml、挥发油:0.72μl/ml、香豆素+挥发油:0.45mg/ml香豆素+0.72μl/ml挥发油)后阿魏酸的转运显著提高。结论:阿魏酸的转运过程可能为被动转运兼存在载体转运,阿魏酸的转运同时受P-gp和MRP外排影响,MRP影响较为明显,白芷有效成分对阿魏酸的转运有促进作用。     

Transport properties of puerarin and effect of Radix Angelicae Dahuricae extract on the transport of puerarin in Caco-2 cell model

Ethnopharmacological relevance

Angelicae Dahurica (Hoffm.)Benth.& Hook.f.ex Franch.&Sav combined with Pueraria labota (Willd.)Ohwi has been widely used as herb-pairs in traditional Chinese medicine (TCM) for utilization of antipyretic analgesic and anti-inflammatory drugs, and modern pharmacological studies have shown that application compatibility of the two drugs has the effects of cardiovascular disease treatment. The previous study has proved that Radix Angelicae Dahuricae extract could enhance the intestinal absorption of puerarin in Pueraria. But the underlying compatibility mechanism of the two herbs remains unknown. In this study we tried to further evaluate the improvement of Radix Angelicae Dahuricae extract on the puerarin using the Caco-2 cell model and explore the transport properties of puerarin through the above research to discuss the possible effect mechanism of Radix Angelicae Dahuricae extract on the transport of puerarin and the underlying compatibility mechanism of the two herbs.

Aim of study

The aim of this work was to study the transport properties of puerarin in Radix Pueraria across Caco-2 cell membrane and to explore how the Radix Angelicae Dahuricae extract affected the transport of puerarin using the well-characterized, human-based intestinal Caco-2 cell model as a platform.

Materials and methods

The bidirectional transport, and the effects of time, drug concentration, pH, P-gp inhibitors (Verapamil, Cyclosporin A), MRP inhibitor (MK-571) and EDTA-Na₂ (tight junction modulator) on the absorption of puerarin were observed. Then the influence of extract of Radix Angelicae Dahuricae on the transport of puerarin was studied. Drug concentration was measured by HPLC and the apparent permeability coefficients (Papp) and apparent permeability ratio (PDR) were calculated.

Results and conclusions

The results showed that the transport (Papp) of puerarin in Caco-2 cell monolayer model had time and concentration dependence, and the transport showed saturation characteristics with the time and concentration of puerarin to a certain degree. The Papp of puerarin transported on Caco-2 cell monolayer model was significantly changed when the specified inhibitors of P-gp were added to the model and the PDR decreased from 1.74 to 0.43. The absorption of puerarin was improved when combined with Radix Angelicae Dahuricae. The intestinal absorption of puerarin is by passive diffusion as the dominating process and active transportation was mediated by P-gp and MRP transporter in Caco-2 cell monolayer model, and Radix Angelicae Dahuricae could enhance the intestinal absorption of puerarin.     

白芷中呋喃香豆素类成分对葛根素、芍药苷、长春新碱肠道转运的影响

目的考察白芷中呋喃香豆素类成分对难吸收药物葛根素、芍药苷、长春新碱吸收的影响,探讨白芷中呋喃香豆素类成分对不同结构药物吸收的影响规律。方法采用Caco-2细胞模型,以各药物透过Caco-2细胞单层的表观渗透系数(Papp)为指标,分别考察白芷中呋喃香豆素类成分(欧前胡素、异欧前胡素、佛手柑内酯、氧化前胡素)对葛根素、芍药苷、长春新碱透过Caco-2细胞单层的影响。结果 4个呋喃香豆素类成分对3种单体成分转运的影响不同,欧前胡素、异欧前胡素、氧化前胡素能显著促进葛根素透过Caco-2细胞单层转运(P0.05、0.01),佛手柑内酯对葛根素透过Caco-2细胞单层转运无明显影响;欧前胡素、佛手柑内酯对芍药苷透过Caco-2细胞单层转运无明显影响,但异欧前胡素、氧化前胡素显著抑制芍药苷透过Caco-2细胞单层转运(P0.05、0.01);欧前胡素、异欧前胡素、氧化前胡素能显著促进长春新碱透过Caco-2细胞单层转运(P0.05、0.01),佛手柑内酯能显著抑制长春新碱透过Caco-2细胞单层转运(P0.05)。结论不同呋喃香豆素对同一药物的肠道转运的影响不同,虽然同为呋喃香豆素,对药物的转运可表现为完全相反的作用。同一呋喃香豆素与不同药物联合使用,其对联合用药物肠道转运的影响也不相同。     

Transport Properties of Puerarin and Effect of Extract of Radix Angelicae dahuricae on Puerarin Intestinal Absorption Using In Situ and In Vitro Models

The root of Angelica dahurica (Radix Angelicae Dahuricae, RAD), which contains coumarins and volatile oil as its main classes of active components, is often given in conjunction with Pueraria root (Radix Puerariae, RP), which contains the phytoestrogen puerarin. The two herbs are considered to be compatible ‘herb‐pairs’ in traditional Chinese medicine. The present investigation investigates the absorption of puerarin from RP and the effect of the total coumarins and volatile oil from RAD on its absorption. The everted gut sac and single‐pass intestinal perfusion methods were used, respectively. The results showed that the absorption of puerarin in the jejunum was significantly increased in the presence of the coumarins and/or volatile oil. The absorption rate constant (K_a) of puerarin increased gradually until the concentration reached 160 µg · mL^?1, after which its absorption became saturated and the apparent permeability (P_app) values significantly decreased. The results showed that the intestinal absorption mechanisms of puerarin involved active transportation processes and that puerarin is likely to be a substrate of P‐gp because verapamil significantly affected its P_app and K_a. The absorption of puerarin significantly increased (p < 0.01) when combined with RAD extracts, as shown by the increase in concentration of puerarin in blood from the hepatic portal vein, supporting the concept of RAD and RP as a compatible herb‐pair. Copyright © 2014 John Wiley & Sons, Ltd.     

外翻肠囊法研究白芷有效组分对配伍"对药"有效成分肠吸收的影响

目的: 考察白芷有效组分香豆素和挥发油分别对配伍"对药"葛根中葛根素、黄芩中黄芩苷、川芎中阿魏酸及甘草中甘草酸、甘草苷肠吸收的影响,探讨白芷对配伍"对药"有效成分肠吸收的影响规律。方法: 采用大鼠外翻肠囊吸收模型,分别考察白芷有效组分配伍各对药(葛根、黄芩、川芎、甘草)前后,葛根中葛根素、黄芩中黄芩苷、川芎中阿魏酸及甘草中甘草酸、甘草苷在不同肠段的吸收情况。结果: 白芷有效组分能显著促进葛根中葛根素(提高1.70倍)、黄芩中黄芩苷(提高4.74倍)的肠吸收作用;白芷有效组分对川芎中阿魏酸肠吸收无显著影响;白芷有效组分对甘草中甘草苷、甘草酸具有显著的肠吸收抑制作用。结论: 白芷-葛根,白芷-黄芩药对配伍应用产生协同治疗作用,不仅表现为不同活性成分作用于机体的不同靶点,还表现为白芷活性成分促进其配伍"对药"活性成分肠道转运。白芷-川芎、白芷-甘草配伍机制可能与白芷对甘草中活性成分肠吸收的影响无关。     

Elucidation of the transport mechanism of baicalin and the influence of a Radix Angelicae Dahuricae extract on the absorption of baicalin in a Caco-2 cell monolayer model

Ethnopharmacological relevance

Angelicae Dahurica (Hoffm.) Benth. & Hook. f. ex Franch. & Sav combined with Radix Scutellariae baicalensis Georgi has been widely used in traditional Chinese medicine (TCM) as an antipyretic analgesic and anti-inflammatory drug. Modern pharmacological studies have demonstrated that the compatible application of these two drugs is an effective treatment for hepatitis. A previous study indicated that a Radix Angelicae Dahuricae extract enhanced the intestinal absorption of the baicalin found in Radix Scutellariae; however, the underlying compatibility mechanism of these two herbs remains unknown. In this study, we further examined the effect of a Radix Angelicae Dahuricae extract on the absorption and transport properties of baicalin in a Caco-2 cell model to determine the compatibility mechanism of these two herbs.

Aim of the study

The aim of this work was to study the transport properties of baicalin in Radix Scutellariae across cell membranes and the effects of a Radix Angelicae Dahuricae extract on baicalin absorption using the well-characterized, human-based intestinal Caco-2 cell model.

Materials and methods

We assessed the absorption, bidirectional transport and toxicity of baicalin using a range of parameters, including drug concentration, pH, a P-glycoprotein (P-gp) inhibitor (Verapamil), an MRP inhibitor (MK-571) and EDTA-Na₂ (tight junction modulator). Next, we studied the influence of a Radix Angelicae Dahuricae extract on the transport of baicalin under the same conditions. Drug concentration was measured by HPLC, and the apparent permeability coefficient (Papp) and apparent permeability ratio (PDR) were subsequently calculated.

Results

The results showed that baicalin is non-toxic within a concentration range of 800 µg/mL to 4800 µg/mL. The transport of baicalin showed time and concentration dependence. The absorption of baicalin was optimal at pH 7.4 in 37 °C; however, the absorption decreased at 4 °C. The Papp of baicalin transport through the Caco-2 cell monolayer model was altered when specific inhibitors of P-gp or MRP were added to the cells. However, there was no significant difference in the PDR value. The Papp of baicalin improved when it was combined with the Radix Angelicae Dahuricae extract. The influence of EDTA-Na₂ on the transport of baicalin showed that the permeability of baicalin significantly increased. The result further indicated that the mechanism of baicalin intestinal absorption in the Caco-2 cell monolayer involves passive transcellular diffusion.

Conclusions

Passive diffusion is the main mode of intestinal absorption of bacalin and it involved in the efflux of proteins. The enhanced intestinal absorption of baicalin by Radix Angelicae Dahuricae can be due to opening of the tight junctions between cells and inhibition of MRP efflux protein expression or function.     

白芷提取物对葛根中葛根素肠吸收的影响研究

目的:考察白芷提取物对葛根素肠吸收的影响,初步探讨白芷提取物促吸收原理,为中药配伍原理提供依据。方法:采用大鼠外翻与大鼠在体单向灌流实验方法,考察在含有白芷提取物时葛根溶液的肠吸收影响,同时考察P-gp抑制剂对葛根肠吸收影响,研究白芷提取物是否对葛根有促吸收作用,进一步考察葛根肠吸收机制。结果:葛根的肠吸收中,回肠>结肠>空肠>十二指肠,加入白芷提取物后,葛根在空肠吸收明显增加。以空肠单向灌流进行实验,葛根素的表观通透系数(Papp)与吸收速率常数(Ka)随药物浓度增大而逐渐减少,含有P-gp抑制剂维拉帕米的葛根素Ka与Papp分别比单纯葛根素吸收增加了2.49,2.60倍(P<0.001)。pH 5.0,6.8下葛根素吸收较pH 7.4的好。结论:葛根的吸收主要是主动吸收,受P-gp外排影响,加入白芷提取物后葛根吸收增加。     

板蓝根提取液中有效成分的吸收转运特性分析

目的:研究板蓝根中有效成分在Caco-2细胞模型中的吸收转运特征。方法:建立Caco-2细胞摄取、转运模型,考察受试化合物对该细胞的安全性,以跨膜电阻值、碱性磷酸酶活性和荧光素钠通透性3个指标检验细胞模型,考察浓度、时间、温度、抑制剂及p H对受试化合物吸收的影响。采用HPLC检测受试化合物,计算其表观渗透系数(Papp)与外排率。结果:板蓝根样品中精氨酸、腺苷能被小肠吸收细胞较好吸收,精氨酸Papp在1.01×10-6~1.35×10~(-6)cm·s~(-1),腺苷Papp在0.40×10~(-6)~0.71×10~(-6)cm·s~(-1)。2种成分在Caco-2细胞中膜通透性良好;精氨酸被吸收程度优于腺苷,精氨酸吸收率50%。板蓝根提取液中精氨酸、腺苷成分外排率(ER)均在1.0~2.0,存在P-糖蛋白(P-gp)外排转运蛋白介导两者的吸收转运,板蓝根样品中存在其他成分促进精氨酸、腺苷的P-gp外排作用。结论:板蓝根药材中精氨酸和腺苷能够被小肠细胞较好地吸收,存在吸收转运方向差异性,且都受到P-gp外排作用。     

川芎嗪在Caco-2细胞单层模型的转运特征及对P-糖蛋白表达的影响

目的 研究川芎嗪在Caco-2细胞单层模型的转运特征以及对P-糖蛋白(P-gp)表达的影响.方法 MTT法确定川芎嗪对Caco-2细胞单层模型作用的安全浓度范围;以Caco-2细胞单层模型研究川芎嗪的双向转运机制,以表观渗透系数(Papp)为检测指标,考察时间、药物浓度以及P-gp抑制剂维拉帕米对川芎嗪转运的影响;Western blotting法检测川芎嗪对P-gp表达的影响.结果 从顶侧(AP)到底侧(BL) (AP→BL),川芎嗪的Papp＞ 10-6 cm/s,表明其吸收性良好;川芎嗪的转运量与其浓度和时间呈正相关,且川芎嗪AP→BL的转运量明显大于BL→AP的转运量;川芎嗪不仅受到P-gp的外排作用,同时也抑制P-gp表达.结论 川芎嗪在Caco-2细胞模型的转运方式为被动转运,且受到P-gp的外排作用,并对P-gp的表达有抑制作用.     

大黄有效成分与附子有效成分配伍在Caco-2细胞模型上的转运分析

目的:研究大黄中大黄酸、大黄素,附子中去甲乌药碱,以及大黄酸、大黄素与去甲乌药碱分别配伍后在Caco-2细胞模型上的转运过程。方法:以大黄酸、大黄素、去甲乌药碱的累积转运量及表观渗透系数(Papp)为指标,采用HPLC对大黄酸、大黄素、去甲乌药碱的含量进行检测,考察大黄酸、大黄素、去甲乌药碱在Caco-2细胞上的转运行为,以及大黄素、大黄酸分别配伍去甲乌药碱后转运行为的变化情况。结果:不同浓度去甲乌药碱的Papp均1×10-7cm·s-1,外排与吸收比值接近1.5,配伍大黄酸、大黄素后去甲乌药碱的Papp显著上升(P0.05)。大黄酸、大黄素配伍去甲乌药碱后前二者的Papp显著下降(P0.05)。结论:去甲乌药碱是1个中等吸收的药物,其吸收方式主要为被动转运。大黄中大黄酸、大黄素可促进附子中去甲乌药碱的在肠吸收,而去甲乌药碱却会抑制大黄酸、大黄素的在肠吸收。     

根皮苷大鼠在体肠吸收特性研究

采用大鼠在体单向肠灌流模型,运用HPLC测定灌流液中根皮苷的含量,研究根皮苷在小肠段和结肠的吸收情况,并考察药物浓度和P-糖蛋白(P-gp)抑制剂对根皮苷吸收的影响,得出根皮苷在体大鼠肠吸收的动力学特征。结果表明根皮苷在大鼠全肠段均有吸收,在空肠段和结肠段吸收较完全,在十二指肠段和回肠段难以吸收;其在不同肠段的吸收速率常数(Ka)和表观吸收系数(P_(app))从大到小依次为空肠结肠十二指肠回肠;不同质量浓度的根皮苷(5.14,10.28,20.56 mg·L~(-1)),其Ka和P_(app)没有显著性差异,提示在实验浓度范围内,根皮苷在大鼠全肠段的吸收没有浓度依赖性,吸收机制可能属于被动扩散;含P-gp抑制剂组和不含P-gp抑制剂组比较,根皮苷的Ka和P_(app)有显著性差异(P0.05),表明根皮苷可能是P-gp底物。