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Iron(III) Complexes of Vitamin B 6 Schiff Base with Boron‐Dipyrromethene Pendants for Lysosome‐Selective Photocytotoxicity
Author(s) -
Sahoo Somarupa,
Podder Santosh,
Garai Aditya,
Majumdar Shamik,
Mukherjee Nandini,
Basu Uttara,
Nandi Dipankar,
Chakravarty Akhil R.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201701487
Subject(s) - chemistry , bodipy , schiff base , singlet oxygen , bioinorganic chemistry , fluorescence , reactive oxygen species , stereochemistry , photochemistry , oxygen , biochemistry , organic chemistry , physics , quantum mechanics
Iron(III) complexes of a vitamin B 6 Schiff base and NNN ‐donor ligands with pendant boron‐dipyrromethene (BODIPY) moieties; namely, [Fe(L 1–3 )(L 4,5 )](NO 3 ) ( 1 – 4 ), where L 1 is benzyl‐bis[(pyridin‐2‐yl)methyl]methanamine (bzdpa in 1 ), L 2 is a noniodinated BODIPY‐appended dipicolylamine ligand (in 2 , 3 ), L 3 is the diiodinated BODIPY analogue in 4 , L 4 is a vitamin B 6 Schiff base, namely 3‐hydroxy‐5(hydroxymethyl)‐4‐{[(2‐hydroxyphenyl)imino]methyl}‐2‐methylpyridine (in 1 , 3 , and 4 ), and L 5 is 2‐[(2‐hydroxyphenylimino)‐methyl]phenol (in 2 ) as a nonpyridoxal Schiff base, were prepared, characterized, and their cellular localization and cytotoxic activity in light and in the dark were studied. The diiodo–BODIPY complex 4 displays remarkable photoinduced cytotoxicity in visible light (400–700 nm), with IC 50 values within 0.11–0.25 µ m and about 200‐fold lower dark toxicity. Complex 3 , being fluorescent, was used for cellular imaging by confocal microscopy. Complex 4 shows supercoiled pUC19 DNA cleavage activity through the generation of singlet oxygen ( 1 O 2 ) as the reactive oxygen species (ROS). Selective uptake of the complexes is observed from competitive cellular incorporation assays in cancer and noncancer cells. The complexes also show no apparent toxicity up to 100 µ m in the immortal human lung epithelial cells HPL1D in both light and the dark. Complex 3 shows preferential accumulation in lysosomes, giving a Pearson's correlation coefficient value of about 0.7.