Browsing by Author "Arnab Dutta"

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Density Functional Theory-Guided Photo-Triggered Anticancer Activity of Curcumin-Based Zinc(II) Complexes
(American Chemical Society, 2023) Rajesh Kushwaha; Virendra Singh; Silda Peters; Ashish K. Yadav; Dependu Dolui; Sukanta Saha; Sujit Sarkar; Arnab Dutta; Biplob Koch; Tumpa Sadhukhan; Samya Banerjee
Photodynamic therapy (PDT) has evolved as a new therapeutic modality for cancer treatment with fewer side effects and drug resistance. Curcumin exhibits PDT activity, but its low bioavailability restricts its clinical application. Here, the bioavailability of curcumin was increased by its complex formation with the Zn(II) center. For a structure-activity relationship study, Zn(II)-based complexes (1-3) comprising N^N-based ligands (2,2′-bipyridine in 1 and 2 or 1,10-phenanthroline in 3) and O^O-based ligands (acetylacetone in 1, monoanionic curcumin in 2 and 3) were synthesized and thoroughly characterized. The X-ray structure of the control complex, 1, indicated a square pyramidal shape of the molecules. Photophysical and TD-DFT studies indicated the potential of 2 and 3 as good visible light type-II photosensitizers for PDT. Guided by the TD-DFT studies, the low-energy visible light-triggered singlet oxygen (1O2) generation efficacy of 2 and 3 was explored in solution and in cancer cells. As predicted by the TD-DFT calculations, these complexes produced 1O2 efficiently in the cytosol of MCF-7 cancer cells and ultimately displayed excellent apoptotic anticancer activity in the presence of light. Moreover, the molecular docking investigation showed that complexes 2 and 3 have very good binding affinities with caspase-9 and p-53 proteins and could activate them for cellular apoptosis. Further molecular dynamics simulations confirmed the stability of 3 in the caspase-9 protein binding site. © 2023 American Chemical Society.
Efficacy of Redox-Active Cu(II) Dipyrrin Complexes toward Electrochemical Reduction of CO2
(American Chemical Society, 2025) Irshad Ali; Gul Afshan; Vishwa Deepak Singh; Arnab Dutta; Daya Shankar Pandey
New D-A-type catalysts based on Cu (II) complexes (C1 and C2) including dipyrrin ligands with phenothiazine/carbazole as the meso-substituent have been described. The complexes have been thoroughly characterized by various methods (1H, 13C, ESI-MS, EPR, and UV-vis studies), and structures of both C1 and C2 unequivocally determined by X-ray single crystal analyses. The catalysts C1 and C2 are stable at room temperature and exhibit Faradaic efficiency values of ∼56% (C1) and ∼46% (C2) toward homogeneous reduction of CO2 to CO. The release of CO has been validated by gas chromatographic (GC) studies. Electron-rich phenothiazine and carbazole included in the catalysts facilitate proton transfer, enabling rapid and selective formation of CO over H2 with FEH2 values of ∼22% for C1 and ∼7% for C2 and turnover numbers (TON) of ∼46 for C1 and ∼21 for C2. Furthermore, the formation of formate ions has been affirmed by ion chromatography (C1, ∼16%; C2, ∼18%). Detailed electrochemical studies and product analyses suggested that C1 displays superior catalytic activity relative to C2 which has been further supported by theoretical studies. © 2025 American Chemical Society.
Green Light-Triggered Photocatalytic Anticancer Activity of Terpyridine-Based Ru(II) Photocatalysts
(American Chemical Society, 2024) Arif Ali Mandal; Virendra Singh; Sukanta Saha; Silda Peters; Tumpa Sadhukhan; Rajesh Kushwaha; Ashish Kumar Yadav; Apurba Mandal; Aarti Upadhyay; Arpan Bera; Arnab Dutta; Biplob Koch; Samya Banerjee
The relentless increase in drug resistance of platinum-based chemotherapeutics has opened the scope for other new cancer therapies with novel mechanisms of action (MoA). Recently, photocatalytic cancer therapy, an intrusive catalytic treatment, is receiving significant interest due to its multitargeting cell death mechanism with high selectivity. Here, we report the synthesis and characterization of three photoresponsive Ru(II) complexes, viz., [Ru(ph-tpy)(bpy)Cl]PF6 (Ru1), [Ru(ph-tpy)(phen)Cl]PF6 (Ru2), and [Ru(ph-tpy)(aip)Cl]PF6 (Ru3), where, ph-tpy = 4′-phenyl-2,2′:6′,2″-terpyridine, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, and aip = 2-(anthracen-9-yl)-1H-imidazo[4,5-f][1,10] phenanthroline, showing photocatalytic anticancer activity. The X-ray crystal structures of Ru1 and Ru2 revealed a distorted octahedral geometry with a RuN5Cl core. The complexes showed an intense absorption band in the 440-600 nm range corresponding to the metal-to-ligand charge transfer (MLCT) that was further used to achieve the green light-induced photocatalytic anticancer effect. The mitochondria-targeting photostable complex Ru3 induced phototoxicity with IC50 and PI values of ca. 0.7 μM and 88, respectively, under white light irradiation and ca. 1.9 μM and 35 under green light irradiation against HeLa cells. The complexes (Ru1-Ru3) showed negligible dark cytotoxicity toward normal splenocytes (IC50s > 50 μM). The cell death mechanistic study revealed that Ru3 induced ROS-mediated apoptosis in HeLa cells via mitochondrial depolarization under white or green light exposure. Interestingly, Ru3 also acted as a highly potent catalyst for NADH photo-oxidation under green light. This NADH photo-oxidation process also contributed to the photocytotoxicity of the complexes. Overall, Ru3 presented multitargeting synergistic type I and type II photochemotherapeutic effects. © 2024 American Chemical Society.
Polypyridyl CoII-Curcumin Complexes as Photoactivated Anticancer and Antibacterial Agents
(John Wiley and Sons Inc, 2023) Ashish Kumar Yadav; Virendra Singh; Rajesh Kushwaha; Dependu Dolui; Rohit Rai; Prodyut Dhar; Arnab Dutta; Biplob Koch; Samya Banerjee
Four new CoII complexes, [Co(bpy)2(acac)]Cl (1), [Co(phen)2(acac)]Cl (2), [Co(bpy)2(cur)]Cl (3), [Co(phen)2(cur)]Cl (4), where bpy=2,2’-bipyridine (1 and 3), phen=1,10-phenanthroline (2 and 4), acac=acetylacetonate (1 and 2), cur=curcumin monoanion (3 and 4) have been designed, synthesized and fully characterized. The X-ray crystal structures of 1 and 2 indicated that the CoN4O2 core has a distorted octahedral geometry. The photoactivity of these complexes was tuned by varying the π conjugation in the ligands. Curcumin complexes 3 and 4 had an intense absorption band near 435 nm, which made them useful as visible-light photodynamic therapy agents; they also showed fluorescence with λem≈565 nm. This fluorescence was useful for studying their intracellular uptake and localization in MCF-7 breast cancer cells. The acetylacetonate complexes (1 and 2) were used as control complexes to understand the role of curcumin. The white-light-triggered anticancer profiles of the cytosol targeting complexes 3 and 4 were investigated in detail. These non-dark toxic complexes displayed significant apoptotic photo-cytotoxicity (under visible light) against MCF-7 cells through ROS generation. The control complexes 1 and 2 did not induce significant cell death in the light or dark. Interestingly, 1-4 produced a remarkable antibacterial response upon light exposure. Overall, the reported results here can increase the boundary of the CoII-based anticancer and antibacterial drug development. © 2023 Wiley-VCH GmbH.
Sonodynamic Cancer Therapy by Mn(I)-tricarbonyl Complexes via Ultrasound-triggered CO Release and ROS Generation
(John Wiley and Sons Inc, 2025) Ashish Kumar Kumar Yadav; Virendra Pratap Singh; Sagar Acharjee; Sukanta Saha; Rajesh Kumar Kushwaha; Arnab Dutta; Biplob Koch; Samya Banerjee
A novel ferrocene conjugated Mn(I)-tricarbonyl complex viz [Mn(Fc-tpy)(CO)3Br] (Mn2) where, Fc-tpy=4′-ferrocenyl-2,2′:6′,2′′-terpyridine was synthesized and fully characterized along with its non-ferrocene analog [Mn(Ph-tpy)(CO)3Br] Ph-tpy=4′-phenyl-2,2′:6′,2′′-terpyridine (Mn1) for ultrasound (US) activated anticancer applications. The X-ray structure of Mn2 confirmed its distorted octahedral geometry. Mn1 and Mn2, for the first time, showed US-triggered release of CO and ROS generation (1O2 and ⋅OH) in an aqueous solution from any Mn(I)-tricarbonyl complexes, indicating its potential for synergetic CO gas therapy and sonodynamic therapy. The above-mentioned in-solution chemistry was successfully translated into in vitro cellular models. These complexes showed unprecedented US-triggered toxicity against T-cell lymphoma and human breast cancer cells (IC50 for Mn2<1 μM) while were minimally toxic without US or against normal spleen and human embryonic kidney cells. Mn2 was ca. 12 fold more anticancer active than Mn1, indicating that the ferrocene conjugation augmented the US sensitivity. The apoptotic sonotoxicity of Mn2 was due to US-promoted mitochondrial depolarization via ROS generation and CO release. The apoptosis was triggered by caspase 3 activation. This is the first report of Mn(I)-tricarbonyl-based sonosensitizers for cancer SDT. Overall, this study, for the first time, establishes the effectiveness of 3d metal carbonyls in SDT. © 2024 Wiley-VCH GmbH.