Enhancing the potency of lithospermate B for inhibiting Na+/K+-ATPase activity by forming transition metal ion complexes
作者:Nan-Hei Lin、Tse-Yu Chung、Feng-Yin Li、Hsin-An Chen、Jason TC Tzen
DOI:10.1038/aps.2013.32
日期:2013.7
To determine whether replacing Mg2+ in magnesium lithospermate B (Mg-LSB) isolated from danshen (Salvia miltiorrhiza) with other metal ions could affect its potency in inhibition of Na+/K+-ATPase activity. Eight metal ions (Na+, K+, Mg2+, Cr3+, Mn2+, Co2+, Ni2+, and Zn2+) were used to form complexes with LSB. The activity of Na+/K+-ATPase was determined by measuring the amount of inorganic phosphate (Pi) liberated from ATP. Human adrenergic neuroblastoma cell line SH-SY5Y was used to assess the intracellular Ca2+ level fluctuation and cell viability. The metal binding site on LSB and the binding mode of the metal-LSB complexes were detected by NMR and visible spectroscopy, respectively. The potencies of LSB complexed with Cr3+, Mn2+, Co2+, or Ni2+ increased by approximately 5 times compared to the naturally occurring LSB and Mg-LSB. The IC50 values of Cr-LSB, Mn-LSB, Co-LSB, Ni-LSB, LSB, and Mg-LSB in inhibition of Na+/K+-ATPase activity were 23, 17, 26, 25, 101, and 128 μmol/L, respectively. After treatment of SH-SY5Y cells with the transition metal-LSB complexes (25 μmol/L), the intracellular Ca2+ level was substantially elevated, and the cells were viable for one day. The transition metals, as exemplified by Co2+, appeared to be coordinated by two carboxylate groups and one carbonyl group of LSB. Titration of LSB against Co2+ demonstrated that the Co-LSB complex was formed with a Co2+:LSB molar ratio of 1:2 or 1:1, when [Co2+] was less than half of the [LSB] or higher than the [LSB], respectively. LSB complexed with Cr3+, Mn2+, Co2+, or Ni2+ are stable, non-toxic and more potent in inhibition of Na+/K+-ATPase. The transition metal-LSB complexes have the potential to be superior substitutes for cardiac glycosides in the treatment of congestive heart failure.
确定用其他金属离子取代从丹参中分离的紫草酸镁 B (Mg-LSB) 中的 Mg2+ 是否会影响其抑制 Na+/K+-ATPase 活性的效力。八种金属离子(Na+、K+、Mg2+、Cr3+、Mn2+、Co2+、Ni2+ 和 Zn2+)用于与 LSB 形成络合物。 Na+/K+-ATP酶的活性通过测量ATP释放的无机磷酸盐(Pi)的量来确定。使用人肾上腺素能神经母细胞瘤细胞系 SH-SY5Y 评估细胞内 Ca2+ 水平波动和细胞活力。分别通过核磁共振和可见光谱检测LSB上的金属结合位点和金属-LSB配合物的结合模式。与天然存在的 LSB 和 Mg-LSB 相比,与 Cr3+、Mn2+、Co2+ 或 Ni2+ 复合的 LSB 的效力增加了约 5 倍。 Cr-LSB、Mn-LSB、Co-LSB、Ni-LSB、LSB 和 Mg-LSB 抑制 Na+/K+-ATPase 活性的 IC50 值为 23、17、26、25、101 和 128 μmol/分别是L。用过渡金属-LSB复合物(25μmol/L)处理SH-SY5Y细胞后,细胞内Ca2+水平显着升高,细胞可存活1天。以 Co2+ 为例的过渡金属似乎是由 LSB 的两个羧酸根基团和一个羰基配位的。 LSB 对 Co2+ 的滴定表明,当 [Co2+] 低于 [LSB] 的一半或高于 [LSB] 时,以 1:2 或 1:1 的 Co2+:LSB 摩尔比形成 Co-LSB 复合物, 分别。 LSB 与 Cr3+、Mn2+、Co2+ 或 Ni2+ 复合,稳定、无毒,并且对 Na+/K+-ATP 酶的抑制更有效。过渡金属-LSB复合物有可能成为治疗充血性心力衰竭的强心苷的优质替代品。