茯苓酸在人源肠Caco-2细胞单层模型的吸收和转运

目的：研究中药茯苓中茯苓酸（pachymic acid，PA）在人肠的吸收和转运。 方法：人源肠Caco－2细胞单层作为药物的肠吸收转运模型，测定PA从绒毛面（AP）到基底面（BL）的渗透性；反相高效液相色谱法测定PA在AP和BL的浓度，紫外检测波长为210nm；计算转运参数和表观渗透系数（Papp），并与在Caco-2细胞单层模型呈良好吸收转运的阳性对照药普萘洛尔和不良吸收转运的阳性对照药阿替洛尔进行比较。 结果：PA由AP到BL方向的Papp值为（9．50±2．20）×10^-7cm／s，由BL到AP方向的Papp值为（11．30±5．90）×10^-7cm／s。在本项研究条件下，普萘洛尔和阿替洛尔的Papp值分别为1．45×10^-5cm／s和4．22×10^-7cm／s。 结论：PA在Caco-2细胞单层馍型的吸收转运呈浓度依赖性，与转运时间呈线性关系；由AP到BL和BL到AP两个方向的转运不良，其Papp值与阿替洛尔的接近；除被动扩散机制外，ATP部分地参与了PA的转运。

Absorption and transport of pachymic acid in the human intestinal cell line Caco-2 monolayers

Objective: To study the absorption and transport of pachymic acid (PA) isolated from the sclerotium of Poria cocos (Schw.) Wolf. in human intestinal epithelium. Methods: By using Caco-2 (the human colonic adenocarcinoma cell lines) cell monolayers as an intestinal epithelial cell model, the permeability of PA was studied from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. The PA was measured by reversed-phase high performance liquid chromatography coupled with UV detector at maximum absorption wavelength of 210 nm. Transport parameters and apparent permeability coefficients (Papp) were then calculated and compared with those of propranolol and atenolol, which were the transcellular transport markers for high and poor permeability respectively. Results: The Papp values of PA were (9.50+/-2.20) 10(-7) cm/s from AP side to BL side, and (11.30+/-5.90) 10(-7) cm/s from BL side to AP side, respectively. Under the condition of this experiment, the Papp values were 1.45x10(-5) cm/s for propranolol and 4.22x10(-7)cm/s for atenolol. Conclusion: PA is transported through the Caco-2 cell monolayer in a concentration-dependent manner and the transport was linear with time. The absorption in apical to basolateral direction and secretion in basolateral to apical direction were poor and their Papp values were comparable to atenolol. Besides passive diffusion of PA, ATP is partially involved in its transport.