Interactions of antimony-oxide clusters with trypanothione have been
modelled to understand their inhibitory activity against leishmaniasis.
Trypanothione is essential for the survival of leishmania parasites
because it is responsible for maintaining their cellular thiol-disulfide
redox regulation. Density functional theory (DFT) calculations show that
the SbV oxide clusters form hydrogen bonds from the oxygens to the amine
and carboxyl group of the trypanothione. The reaction between
trypanothione and the SbV oxide cluster does not break the S-S bond of
trypanothione, whereas the reaction with antimony-oxide clusters
containing at least one SbIII atom leads to dissociation of the S-S bond
of both the oxidized and the reduced form of trypanothione suggesting
that antimony-oxide clusters with at least one SbIII atom may destroy
trypanothione that is vital for the parasite metabolism.