@article{APS7931,
author = {Nan-Hei Lin and Tse-Yu Chung and Feng-Yin Li and Hsin-An Chen and Jason TC Tzen},
title = {Enhancing the potency of lithospermate B for inhibiting Na+/K+-ATPase activity by forming transition metal ion complexes},
journal = {Acta Pharmacologica Sinica},
volume = {34},
number = {7},
year = {2016},
keywords = {},
abstract = {Nan-Hei LIN1, #, Tse-Yu ChUnG1, #, Feng-Yin Li2, Hsin-an CHEN3, 4, *, Jason TC Tzen1, 5, 6, *
1Graduate Institute of Biotechnology and 2Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan, China; 3Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, Taipei 11031, Taiwan, China; 4Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan, China; 5School of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, China; 6Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan, China
Aim: 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.
Methods: 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.
Results: 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.
Conclusion: 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.
Keywords: cardiac glycoside; lithospermate B; Salvia miltiorrhiza; transition metal; metal complex; Na+/K+-ATPase; congestive heart failure; traditional Chinese medicine
The work was supported by a grant to Jason TC TZEN of National Chung-Hsing University, Taiwan, China (NCHU-101D073).
# These two authors contributed equally to this work.
* To whom correspondence should be addressed.
E-mail dtsurga6@gmail.com (Hsin-An CHEN); TCTZEN@dragon.nchu.edu.tw (Jason TC Tzen)
Received 2012-12-13 Accepted 2013-03-11},
issn = {1745-7254}, url = {http://www.chinaphar.com/article/view/7931}
}