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

Abstract

To study the absorption and transport of pachymic acid (PA) isolated from the sclerotium of Poria cocos (Schw.) Wolf. in human intestinal epithelium. 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. 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. 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.