5-Dimethylaminopropylamino-8-hydroxytriazoloacridinone,
C-1305, being the close structural analogue of the clinically tested imidazoacridinone anti-tumour agent,
C-1311, expressed high activity against experimental tumours and is expected to have more advantageous pharmacological properties than
C-1311. The aim of this study was to elucidate the role of selected liver
enzymes in the metabolism of
C-1305. We demonstrated that the studied triazoloacridinone was transformed with rat and human liver microsomes, HepG2
hepatoma cells and with human recombinant
flavin-containing
monooxygenases FMO1,
FMO3 but not with CYPs. Furthermore, this compound was an effective inhibitor of
CYP1A2 and
CYP3A4. The product of FMO catalysed metabolism was shown to be identical to the main metabolite from liver microsomes and HepG2 cells. It was identified as an N-
oxide derivative and, under
hypoxia, it underwent retroreduction back to
C-1305, what was extremely effective with participation of
CYP3A4. In summary, this work revealed that the involvement of the P450 enzymatic system in microsomal and cellular metabolism of
C-1305 was negligible, whereas this agent was an inhibitor of
CYP1A2 and
CYP3A4. In contrast,
FMO1 and
FMO3 were crucial for metabolism of
C-1305 by liver microsomes and in HepG2 cells, which makes
C-1305 an attractive potent anti-tumour agent.