Ishizuka K, Kanayama A, Satsu H, Miyamoto Y, Furihata K, Shimizu M
Department of Applied Biological Chemistry, The University of Tokyo, Yayoi, Japan.
Biosci Biotechnol Biochem. 2000 Jun;64(6):1166-72. doi: 10.1271/bbb.64.1166.
An ethanol extract from sesame seeds inhibited the taurine uptake in human intestinal epithelial Caco-2 cells. The uptake of such alpha-amino acids as leucine and glutamic acid was not inhibited by the extract, indicating that this inhibition is specific to the taurine uptake. The unknown inhibitor in the sesame extract was purifled by reversed-phase HPLC by monitoring the inhibitory effect on taurine uptake. The isolated substance was identified as lysophosphatidylcholine, linoleoyl (Lyso-PC), by NMR and MS analysis. Lyso-PC inhibited the taurine uptake in a dose-dependent manner with an IC50 value of approximately 200 microM. Although Lyso-PC is known to be a surface active and cell lytic compound, neither damage nor loss of integrity of the Caco2 cell monolayer was apparent after treating with 200 microM Lyso-PC. Inhibition was observed by incubating cells with Lyso-PC for only 1 min prior to the uptake experiments. These results suggest the direct effect of Lyso-PC on the cell membrane to be the main mechanism for this inhibition. Lyso-PC may play a role in the regulation of certain intestinal transporters.
芝麻籽的乙醇提取物抑制了人肠上皮Caco-2细胞对牛磺酸的摄取。亮氨酸和谷氨酸等α-氨基酸的摄取未被该提取物抑制，表明这种抑制作用对牛磺酸摄取具有特异性。通过监测对牛磺酸摄取的抑制作用，利用反相高效液相色谱法对芝麻提取物中的未知抑制剂进行了纯化。通过核磁共振和质谱分析，鉴定出分离出的物质为溶血磷脂酰胆碱，亚油酰基（Lyso-PC）。Lyso-PC以剂量依赖性方式抑制牛磺酸摄取，IC50值约为200μM。尽管已知Lyso-PC是一种表面活性和细胞裂解化合物，但用200μM Lyso-PC处理后，Caco2细胞单层未出现明显损伤或完整性丧失。在摄取实验前仅用Lyso-PC孵育细胞1分钟就观察到了抑制作用。这些结果表明，Lyso-PC对细胞膜的直接作用是这种抑制的主要机制。Lyso-PC可能在某些肠道转运体的调节中发挥作用。
