Transepithelial transport characteristics of Hydroxysafflor yellow A across cellular monolayers and the effects of the influx and efflux transporters

Abstract

Hydroxysafflor yellow A (HSYA), the major biologically active constituent distributed in the florets of Carthamus tinctorius L. (safflower), is concerned with potential health-promoting functions against cardiovascular diseases. However, little information on clarifying the intestinal absorption characteristics of HSYA has been reported, which has limited its widespread application in the medical and healthcare fields. The intention of this research was to systematically characterize the transepithelial transport of HSYA using in vitro cell monolayer models (Caco-2, mucus-producing Caco-2/HT29-MTX-E12, MDCKⅡ and P-gp overexpressed MDCKⅡ-MDR1 cell monolayers). The apparent permeability coefficient (Papp) from the apical to the basolateral side of HSYA is approximately (4.30 ± 0.22) × 10⁻⁸ cm/s, suggesting that HSYA is poorly absorbed across the intestinal epithelium. The transport and uptake of HSYA depends on time, concentration, pH and temperature, and the Papp values increase with ethylene diamine tetraacetic acid pretreatment, indicating that the transport mechanisms of HSYA include passive diffusion (transcellular and paracellular pathways) and carrier-mediated transport. Meanwhile, transporter inhibitors were added in transport and uptake experiments, the results showed that carrier-mediated efflux and influx transport of HSYA is relevant to P-glycoprotein and H⁺ correlative transporters (e.g., peptide transporter 1, monocarboxylic acid transporter). In addition, the mucus layer acts as a barrier to HSYA absorption, as evidenced by a decrease in Papp (22–47%) and cellular uptake (18%) in the coculture model compared to the Caco-2 cell model. Detailed knowledge on the transepithelial transport of HSYA would provide insights to improve the pharmacological activities of HSYA and expand its application in food and healthcare fields.