Abstract:
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[EN] Mitochondria-targeting drugs and diagnostics are used in the monitoring and treatment of
mitochondrial pathologies. In this respect, a great number of functional compounds have been made
mitotropic by covalently ...[+]
[EN] Mitochondria-targeting drugs and diagnostics are used in the monitoring and treatment of
mitochondrial pathologies. In this respect, a great number of functional compounds have been made
mitotropic by covalently attaching the active moiety onto a triphenylphosphonium (TPP) cation.
Among these compounds, a number of molecular detectors for reactive oxygen species (ROS) are
based on fluorescent and chemiluminescent probes. In this regard, luminol (probably the most widely
known chemiluminescent molecule) has been employed for a number of biological applications,
including ROS detection. Its oxidation under specific conditions triggers a cascade of reactions,
ultimately leading to the excited 3-aminophthalate (3AP *), which emits light upon deactivation.
Hence, the photophysical interaction between the light-emitting species 3AP * and TPP cations needs
to be evaluated, as it can add valuable information on the design of novel emission-based mitotropic
systems. We herein investigate the quenching effect of ethyltriphenylphosphonium cation onto
substituted 3-aminophthalates. These were prepared in situ upon hydrolysis of the corresponding
anhydrides, which were synthesized from 3-aminophthalimides. Steady-state fluorescence and timeresolved
experiments were employed for the evaluation of a possible electron transfer quenching
by phosphonium ions. Our experimental results confirmed such quenching, suggesting it is mainly
dynamic in nature. A minor contribution of static quenching that was also detected is attributed
to complex formation in the ground state. Accordingly, the chemiluminescence of luminol was
indeed strongly reduced in the presence of phosphonium ions. Our results have to be taken into
account during the design of new chemiluminescent mitotropic drugs or diagnostic agents of the
luminol family.
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Thanks:
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This project was financially supported by the European Union's Horizon 2020 framework program for research and innovation under grant agreement no. 712921. T.M. and A.P. would like to thank the State Scholarships Foundation ...[+]
This project was financially supported by the European Union's Horizon 2020 framework program for research and innovation under grant agreement no. 712921. T.M. and A.P. would like to thank the State Scholarships Foundation (IKY) for financial support through Ph.D. fellowships through the "Strengthening of Human Resources through Doctoral Research" program of the Operational Program "Human Resource Development, Education and Lifelong Learning" 2014-2020, co-financed by the European Union (European Social Fund ESF) and Greek national funds. M.A.M. and G.M.R.-M. thank the Generalitat Valenciana (Prometeo Program/2017/075) for financial support.
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