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Poster presentation 
56 
(TETRAHYDROXYETHYL-1,4-NAPHTHOQUINONYL)OXY-
UREA – METABOLITES OF THE DRUG HISTOCHROME 
A. Е. Zakirova, R. S. Popov, V. V. Makhankov, V. Ph. Anufriev 
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Russian Academy of 
Sciences, 690022 Vladivostok, Russia 
By high-resolution HPLC coupled with mass spectrometry using a deuterium label, it 
was found that the mice renal excretions after histocrome injection contain 1-((6-ethyl-
2,3,5,8-tetrahydroxy-1,4-naphthoquinone-7-yl)oxy)urea and its 3-methoxy derivative. 
Histochrome® series drugs are effective for the treatment of cardiac and ophthalmic 
diseases. Despite extensive experience in the use of histochrome, to date, the structures 
of its metabolites have not been systematically studied. 
Earlier, by high-resolution HPLC-MS/MS, using a deuterium label, it was found that 
in the renal excretions of mice after injection of histochrome, in addition to the drug 
substance echinochrome (
1
), its methoxy derivatives and their monoglucuronides occur. 
We continued the research related to the search for metabolites possibly responsible for 
the biological activity of histochrome. Two products with t
R
9.4 and 10.3 min were 
detected by high-resolution HPLC-MS/MS. Their negative ion mode mass spectra 
contain peaks of molecular ions [M-H]
-
m/z
326.0712 and 
m/z
340.0844, respectively. 
The difference between the position of the peak of the molecular ion [M-H]
-
, 
m/z
326.0712, the first of them and its main fragment peak 
m/z
267.0474 is 59.0235 units of 
mass. This atomic mass, with a high degree of probability, corresponds to the structural 
fragment of urea NH
2
CONH
-
(
m/z
: 59.0240). The absence of a signal with 
m/z
249.001 
in the spectrum indicates the blocking of the hydroxyl group adjacent to the ethyl 
radical of echinochrome, that is, the presence of the fragment NH
2
CONH
-
at position 6. 
Thus, the detected product has the structure 1-((2,3,5,8-tetrahydroxy-7-ethyl-1,4-
naphthoquinone-6-yl)oxy)urea(
2a
).
The second product molecular ion peak [M-H]
-
with 
m/z
340.0844 (calculated data 
340.0866, 

0.0022) corresponds to two structures