Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.
Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan 71004, Taiwan.
Int J Mol Sci. 2020 Dec 9;21(24):9369. doi: 10.3390/ijms21249369.
Pentagalloyglucose (PGG, penta--galloyl-β-d-glucose; 1,2,3,4,6-pentagalloyl glucose), a pentagallic acid ester of glucose, is recognized to possess anti-bacterial, anti-oxidative and anti-neoplastic activities. However, to what extent PGG or other polyphenolic compounds can perturb the magnitude and/or gating of different types of plasmalemmal ionic currents remains largely uncertain. In pituitary tumor (GH) cells, we found out that PGG was effective at suppressing the density of delayed-rectifier K current () concentration-dependently. The addition of PGG could suppress the density of proton-activated Cl current () observed in GH cells. The IC value required for the inhibitory action of PGG on or observed in GH cells was estimated to be 3.6 or 12.2 μM, respectively, while PGG (10 μM) mildly inhibited the density of the -mediated K current or voltage-gated Na current. The presence of neither chlorotoxin, hesperetin, kaempferol, morin nor iberiotoxin had any effects on density, whereas hydroxychloroquine or 4-[(2-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5yl)oxy] butanoic acid suppressed current density effectively. The application of PGG also led to a decrease in the area of voltage-dependent hysteresis of elicited by long-lasting isosceles-triangular ramp voltage command, suggesting that hysteretic strength was lessened in its presence. In human cardiac myocytes, the exposure to PGG also resulted in a reduction of ramp-induced density. Taken literally, PGG-perturbed adjustment of ionic currents could be direct and appears to be independent of its anti-oxidative property.
五没食子酰葡萄糖（PGG，五没食子酰基-β-D-葡萄糖；1,2,3,4,6-五没食子酰葡萄糖）是葡萄糖的五没食子酸酯，已被证明具有抗菌、抗氧化和抗肿瘤活性。然而，PGG 或其他多酚化合物在多大程度上可以改变不同类型质膜离子电流的幅度和/或门控仍很大程度上不确定。在垂体瘤（GH）细胞中，我们发现 PGG 有效抑制延迟整流钾电流（）的密度，呈浓度依赖性。PGG 的添加可以抑制在 GH 细胞中观察到的质子激活 Cl 电流（）的密度。PGG 对 GH 细胞中观察到的 或 的抑制作用的 IC 值估计分别为 3.6 或 12.2 μM，而 PGG（10 μM）轻度抑制 - 介导的 K 电流或电压门控 Na 电流的密度。氯毒素、橙皮苷、山奈酚、杨梅素或 Iberiotoxin 的存在对 密度均无影响，而羟氯喹或 4-[(2-丁基-6,7-二氯-2-环戊基-2,3-二氢-1-氧代-1H-茚-5 基)氧基]丁酸则能有效抑制电流密度。PGG 的应用也导致由长等腰三角形斜坡电压命令诱发的 诱发的电压依赖性滞后面积减小，表明其存在时滞后强度降低。在人心肌细胞中，PGG 的暴露也导致斜坡诱导的 密度降低。从字面上看，PGG 干扰离子电流的调节可能是直接的，并且似乎与其抗氧化特性无关。
