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2- and 2,7-substituted pyridine pyrenes derivatives and their DNA/RNA interactions

Pyrene is one of the most frequently studied fluorophore due to its environmental emission sensitivity and tendency to excimers and exciplexes formation. 1-, 3-, 6- and 8-substituted pyrenes are already well known, while 2- and 7- substituted ones are less researched while possesing very interesting photophysical properties. Planar structure of pyrene allows “aromatic stacking” with nucleobases, also intercalation between DNA/RNA basepairs and possibility of groove binding. Our preliminary studies indicated strong interactions of cationic analogues (1M and 2M) with ct-DNA, mainly based on intercalation. Only the monocation 1M showed a pronounced fluorescent selectivity between various DNAs and RNAs, in contrast to the less selective 2M. Neutral, monopyridine analogue 1 binds to DNA upon protonation at pH 5 (biorelevant because of tumor tissues acidity), with increase in pyrene excimer emission. Biological studies on the lung tumor cell line (A549) indicated for 1, 1M, and 2M a significant increase in cytotoxicity upon illumination, which was explained by the singlet oxygen generation and the consequent intense action of ROS species. New compounds with an intense fluorescent response and photo-induced bioactivity are promising candidates for new theranostic agents.

2- and 2, 7-pyridine pyrenes ; noncovalent interactions with DNA/RNA ; fluorescence ; cytotoxicity ROS species

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