Original Article

Detecting metabolites of different transition metallithospermate B complexes after intravenous injection in rats

Ying-Jie CHEN, Tse-Yu CHUNG, Wen-Ying CHEN, Chung-Yu CHEN, Maw-Rong LEE, Tzyy-Rong JiNN, Jason TC TzEN
DOI: 10.1038/aps.2014.37

Abstract

Ying-Jie CHEN1, Tse-yu ChUnG1, Wen-Ying CHEN2, Chung-Yu CHEN3, Maw-Rong LEE3, Tzyy-Rong Jinn4, Jason TC Tzen1, 4, 5, *
1Graduate Institute of Biotechnology, 2Department of Veterinary Medicine and 3Department of Chemistry, National Chung Hsing University, Taichung 40227, Taiwan, China; 4School of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, China; 5Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan, China

Aim: Lithospermate B (LSB) isolated from the traditional Chinese medicine danshen (Salvia miltiorrhiza) is an effective Na+/K+-ATPase inhibitor and used to treat congestive heart failure. The inhibition of LSB on Na+/K+-ATPase is potentiated by forming complexes with transition metal ions. Here we investigated the safety and metabolites of different transition metal-LSB complexes in rats.
Methods: LSB complexed with six different transition metal ions (Mg2+, Zn2+, Cr3+, Co2+, Ni2+ and Mn2+) were prepared. Adult male SD rats were injected with the different metal-LSB complexes (50 mg/kg, iv), and their bile and blood samples were collected. The metabolites of the metal-LSB complexes in the samples were analyzed using mass spectroscopy.

Results: In rats injected with LSB complexed with Mg2+, Zn2+, Cr3+, Ni2+ or Mn2+, LSB and its four putative metabolites were equivalently detected in their bile samples. Mn2+-LSB exhibited distinct metabolite profiles compared with the other four metal-LSB complexes. The four putative metabolites were identified as 3-monomethyl-LSB, 3,3''-dimethyl-LSB, 3,3'''-dimethyl-LSB and 3,3'',3'''-trimethyl-LSB. The tracking of successive bile samples of rats injected with Mg2+-LSB, Zn2+-LSB and Mn2+-LSB concurrently demonstrated that LSB was firstly methylated at position 3, then at position 3'', and, finally, the 3''' hydroxyl group. All rats injected with Co2+-LSB died.

Conclusion: Zn2+-LSB, Cr3+-LSB, Ni2+-LSB or Mn2+-LSB produces identical four methylated metabolites of LSB in rats, and seemed to be as safe as LSB or Mg2+-LSB.


Keywords: lithospermate B; transition metal complex; drug metabolism; metabolite; methylation; Na+/K+-ATPase inhibitor; danshen; traditional Chinese medicine

The work was supported by a grant to Jason TC TZEN of National Chung-Hsing University (NCHU-102D604), Taiwan, China.
* To whom correspondence should be addressed.
E-mail TCTZEN@dragon.nchu.edu.tw
Received 2014-01-24 Accepted 2014-03-31
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