Nilmadhab Roy

Herein, we have introduced a series of half-sandwich Ru(II)arene(N^N bpy/phen)-based RAPTA complexes for brain cancer therapy. Among all the synthesized complexes, [(η⁶-p-cymene)Ru^II(κ²-N,N-4,7dimethyl phenanthroline)(PTA)]·2PF₆ (4c) and [(η⁶-p-cymene)Ru^II(κ²-N,N-4,7diphenyl phenanthroline)(PTA)]·2PF₆ (4d) showed outstanding potency against the T98G, LN229 and U87MG cancer cells. The antiproliferative activity of these complexes was reinforced by neurosphere, DNA intercalation, agarose gel electrophoresis, cell cycle analysis and time-dependent ROS detection assays. The real-time reverse transcription (RT)-polymerase chain reaction (PCR) study showed that complex 4c inhibited the TNF-α-induced NF-κB phosphorylation in glioma cells. Moreover, the in vivo biodistribution of complex 4c in different organs and the morphological patterns of widely used zebrafish embryos due to toxic effects have been evaluated.

DNA-targeting half-sandwich [Ru(η⁶-p-cymene)(N^O 8-hydroxyquinoline)(PTA)] complexes have been developed for human brain cancer cell therapy.

To reduce the side effects of marketed cancer drugs against triple negative breast cancer cells we have reported mitochondria targeting half-sandwich iridium(III)-Cp*-arylimidazophenanthroline complexes for MDA-MB-468 cell therapy and diagnosis. Out of five Ir(III) complexes (IrL1–IrL5), [iridium(III)-Cp*-2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline]PF₆ (IrL1) has exhibited the best cytoselectivity against MDA-MB-468 cells compared to normal HaCaT cells along with excellent binding efficacy with DNA as well as serum albumin. The subcellular localization study of the complex revealed the localization of the compound in cytoplasm thereby pointing to a possible mitochondrial localization and consequent mitochondrial dysfunction via MMP alteration and ROS generation. Moreover, the IrL1 complex facilitated a substantial G₁ phase cell-cycle arrest of MDA-MB-468 cells at the highest tested concentration of 5 μM. The study verdicts support the prospective therapeutic potential of the IrL1 complex in the treatment and eradication of triple negative breast cancer cells. These results validate that these types of scaffolds will be fairly able to exert great potential for tumor diagnosis as well as therapy in the near future.

GSH-resistant, hypoxia active iridium( iii )–Cp*-(imidazo[4,5- f ][1,10]phenanthrolin-2-yl)phenol complexes were developed as highly cytoselective anticancer agents and mitochondria-targeting CSC therapeutic agents.

To unearth suitable complexes that are capable of inhibiting the growth of MDA-MB-468 and Caco-2 cells, 2,2′-bipyrimidine-based luminescent Ru(II)/Ir(III)–arene monometallic and homo- and hetero-bimetallic complexes were synthesized. The complex [(η⁶-p-cymene)(η⁵-Cp*)Ru^IIIr^IIICl₂(K²-N,N-bipyrimidine)](PF₆)₂ [LRuIr] exhibited the best potency in both cells along with good GSH stability and strong binding efficacy with the biomolecules. The apoptotic event occurred in MDA-MB-468 cancer cells via cell cycle arrest.

An efficient green protocol for the synthesis of luminescent biotin-conjugated CdSe quantum dots has been developed for bioimaging applications.

Quinoxaline derivatives play versatile roles in various fields of science. Thus different types of scaffolds have been designed with these quinoxaline moieties to make them more efficient for preparation of various biologically active materials in the pharmaceutical industry. The ability of quinoxaline moieties has been reinforced by introducing triazole rings into them with the aid of a “click reaction” following environmentally friendly green techniques in the presence of a Cu(II) catalyst as well as in the presence of a CuO nanomaterial under microwave irradiation. The novelty of our work is being highly focussed on the introduction of unsymmetrical triazole rings with the isolation of mono triazolyl quinoxaline derivatives using an Ir(I) catalyst in aqueous medium and on the capability of the CuO nanomaterial in catalyzing a “click reaction” in various biological media. The role of our synthsized bis(trizolylmethyl)quinoxaline compounds as cytotoxic agents has been confirmed with clear evidence from a DNA and BSA binding study, stability study, viscosity study and MTT assay. Due to the detecting ability of live cancer cells, high cellular uptake, biocompatibility and high cytoselectivity of these scaffolds, ultimately compound 6g has been established as a cancer theranostic drug.

Of late, cancer has become a terrible disease affecting people throughout the world. Keeping this in mind, we tried to design drugs that are more lipophilic, target-specific, water-soluble, cytoselective and fluorescent. In this regard, we reported novel ruthenium(II)-p-cymene imidazophenanthroline scaffolds as effective DNA targeting agents. The planarity of imidazophenanthroline ligands caused the Ru(II) complex to be a good intercalator. An extended π-electronic conjugation was introduced in the imidazophenanthroline moieties through the Suzuki and Sonogashira coupling reactions. Here, we synthesized nine Ru(II) complexes (16a–b, 17a–d, and 19a–c). Among these, [(η⁶-p-cymene)RuCl(K²-N,N-2-(4′-methyl-[1,1′-BIphenyl]-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline)]·PF₆ (16b) exhibited the best potency and selectivity with excellent cellular uptake; [(η⁶-p-cymene)RuCl(K²-N,N-2-(4-(phenylethynyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)]·PF₆ (17a) acted as a cytoselective probe for live cell imaging.