Organoruthenium metallocycle induced mutation in gld-1 tumor suppression gene in JK1466 strain and appreciable lifespan expansion

Four Ru(II) complexes (A2-A5) were synthesized from the reaction of coumarin Schiff base ligands (7da2-tsc, 7da3-mtsc, 7da4-etsc and 7da5-ptsc) with [RuHCl(CO)(PPh3)3]. The compounds were characterized by FT-IR, UV-Vis, 1H, 13C and 31P NMR, mass spectrometry and crystallographic analysis. Calf Thymus DNA (CT-DNA) binding studies revealed the intercalative mode of binding of the complexes with DNA. The results of Bovine serum albumin (BSA) binding studies established the interaction between BSA followed static quenching mechanism. The cytotoxic effects of the complexes and the ligands were evaluated against breast (MCF-7 and MDA-MB-231) and lung carcinoma cell lines (A549 and NCI-H460) using MTT assay. Complex A4 demonstrated potent cytotoxic effects on both breast and lung cancer cells. Furthermore, morphological observations and FACS analysis showed the decrease in cell density by complex A4 by induced morphological changes and apoptotic body formation and cell death in both breast and lung cancer cells. Moreover, the invertebrate model Caenorhabditis elegans was employed to assess the in vivo anticancer activity of compound A4. The findings indicated that the treatment with A4 reduced tumor development and significantly extended organismal lifespan by 64 % in the tumoral strain JK1466 without adversely affecting essential physiological functions of the worm. Additionally, A4 demonstrated an upregulation of two crucial antioxidant defense genes. Overall, these results suggested that the compound A4 can be a potential candidate with novel chemotherapeutic applications.

Effect of ruthenium(II) complexes on MDA-MB-231 cells and lifespan/tumor growth in gld-1mutant, Daf-16 TF and stress productive genes: A perspective study

Pincer type coumarin based N-substituted semicarbazone ligands HL1-4 and their corresponding ruthenium(II) complexes (1-4) were synthesized, analyzed and confirmed by various spectro analytical techniques. The molecular structure of the ligand HL3 and complex 3 was confirmed by single crystal X-ray diffraction analysis. The stoichiometry of complexes 1, 2 and 4 was confirmed by high resolution mass spectroscopy (HRMS). The binding affinity of the compounds with CT-DNA (Calf Thymus DNA) and BSA (Bovine Serum Albumin) was established by absorption and emission titration methods. The results of In vitro cytotoxicity showed the significant cytotoxic potential of the complexes against MDA-MB-231 cells (TNBC- Triple-negative breast cancer). Among the complexes, 1 and 4 have shown appreciable results. Further, antimigratory activity against the MDA-MB-231 cells was studied for the complexes 1 and 4. The percentage cell cycle arrest, apoptosis and necrosis were explored by flow cytometry. The in vivo anti-tumor activity of the complexes 1 and 4 using C. elegans as model organism was established by using the tumoral C. elegans strain JK1466 (gld-1(q485)), which bears a mutation in the gld-1 tumor suppressor gene. We have determined the effect of our complexes on tumor gonad reduction and found to be non toxic to the JK1466 worms and they have prolonged their mean lifespan with potential antioxidant ability by overcoming stress responses. Overall, our study reported herein demonstrated that the complexes 1 and 4 could be established as potential metallo-drugs substantiating further exploration.

Investigation on CT-DNA and Protein Interaction of New Pd(II) Complexes Involving Ceftazidime and 3-Amino-1,2,3-triazole: Synthesis, Characterization, Biological Impact, Anticancer Evaluation, and Molecular Docking Approaches

Two new palladium (II) complexes, [Pd(CAZ)(OH2 )2 ]2+ (1) and [Pd(3-AT)(OH2 )2 ]2+ (2), (CAZ=ceftazidime, and 3-AT=amitrole) were synthesized and studied for their potential as anticancer drugs with low toxicity and high potency. To fully characterize these complexes, we conducted elemental analysis and FT-IR studies. Furthermore, we irradiated the complexes with Indian 60 Co gamma rays and thoroughly evaluated their antimicrobial properties. Our results demonstrate that the inhibitory activity of complexes was significantly enhanced against (G+) bacteria and fungi. Additionally, we probed the complexes' interaction with CT-DNA and BSA using various techniques, including UV-vis spectroscopy, thermal denaturation, viscometry, gel electrophoresis, and molecular docking studies. Our findings conclusively demonstrate that these complexes possess a strong binding interaction with CT-DNA via minor groove binding and/or electrostatic interactions, as well as excellent binding affinity to BSA. Finally, we conducted a cytotoxicity assay that clearly indicates these complexes hold immense promise as cell growth inhibitors against MCF-7 and HCT-116.

A novel water-soluble thiosemicarbazone Schiff base ligand and its complexes as potential anticancer agents and cellular fluorescence imaging

A novel fluorescent ligand (H₂LCl⋅1.5CH₃OH, 1) was synthesized and metal complexes of 1 with Mn(II), Fe(III), Ni(II), Cu(II), and Zn(II) were obtained as Mn(HL)₂Cl₂ (2), Fe(HL)₂Cl₃⋅3H₂O (3), Ni(L)(HL)Cl⋅8H₂O (4), Cu(HL)Cl₂⋅4H₂O (5), Zn(H₂L)Cl₃ (6), respectively. These compounds were identified by spectroscopic methods, elemental analysis, molar conductivity, and single-crystal X-ray crystallography. According to the crystal structure of 4 nickel (II), center is surrounded by two ligands in a distorted octahedral geometry. The ligand and its complexes are soluble in water and have excellent stability. In vitro anti-proliferative activity of these compounds was evaluated against human breast adenocarcinoma (MCF-7) and human lipo-sarcoma (SW-872) as cancer cells and human fibroblasts (HFF-2) as normal cells by MTT assay. Interestingly, complex 5 exhibited excellent activity against both cancer cells with low IC₅₀ value 22.18 ± 0.35 μg/mL (35.66 ± 0.56 μM) for SW-872 and 79.41 ± 3.54 μg/mL (127.6 ± 5.69 μM) for MCF-7 among the compounds and in comparison with paclitaxel (PTX) which acts finely. Morphological changes were evaluated by flow cytometry that revealed apoptosis is the main cause of cell death. Likewise, cell cycle studies indicated the cell cycle arrest in the G₁ and S phases for complex 5 against MCF-7 and SW-872 cancer cells, while complex 6 could arrest the MCF-7 and SW-872 cells in G₂ and G₁ phases, respectively. All of the compounds are fluorescent which enabled us to monitor the uptake and intracellular distribution in living human cancer cells by fluorescence microscopy.

Nickel Complexes Bearing ONS Chelating Ligands: A Promising Contender for In Vitro Cytotoxicity Effects on Human Pancreatic Cancer MIA-PaCa-2 Cells

The highly chronic human pancreatic cancer cell is one of the major reasons for cancerous death. Nickel complexes are recently gaining interest in anticancer activities on different types of cancer cells. Hence, in this study, we synthesized and characterized a series of ONS donor ligands [2-HO-C₆H₄-CH═N-(C₆H₄)-SH] (L1), [2-OH-3-OMe-C₆H₃-CH═N-(C₆H₄)-SH] (L2), [2-OH-3,5-(C(Me)₃)₂-C₆H₂-CH═N-(C₆H₄)-SH] (L3), [2-OH-C₆H₄-CH═N-(C₆H₄)-SMe] (L4), [2-OH-3-OMe-C₆H₃-CH═N-(C₆H₄)-SMe] (L5), [2-OH-3,5-(C(Me)₃)₂-C₆H₂-CH═N-(C₆H₄)-SMe] (L6) and their Ni(II) metal complexes [(MeOH)Ni(L1-L1-4H)] (1), [(MeOH)Ni(L2-L2-4H)] (2), [(MeOH)Ni(L3-L3-4H)] (3), [(L4-H)₂Ni] (4), [(L5-H)₂Ni] (5), and [(L6-H)₂Ni] (6). The single-crystal X-ray diffraction data of complexes 1 and 4 were collected to elucidate the geometry around the metal center. The anticancer activity of complexes 1-6 was investigated on human pancreatic cancer cell line MIA-PaCa-2, which revealed that complexes 4 and 6 were the most significantly effective in decreasing the cell viability of cancer cells at the lowest dose. The structure parameters obtained from single-crystal X-ray diffraction data are found to be in good agreement with the data from density functional theory and Hirshfeld surface analysis for complex 1.

Synthesis, characterization of ruthenium(II), nickel(II), palladium(II), and platinum(II) triphenylphosphine-based complexes bearing an ONS-donor chelating agent: Interaction with biomolecules, antioxidant, in vitro cytotoxic, apoptotic activity and cell cycle analysis

Four new transition metal complexes, [M(PPh₃)(L)]^.CH₃OH (M = Ni(II) (1), Pd(II) (2)) [Pt (PPh₃)₂(HL)]Cl (3) and [Ru(CO)(PPh₃)₂(L)] (4) (H₂L = 2,4-dihydroxybenzaldehyde-S-methyldithiocarbazate, PPh₃ = triphenylphosphine) have been synthesized and characterized by elemental analyses (C, H, N), FTIR, NMR (¹H, ³¹P), ESI-MS and UV-visible spectroscopy. The molecular structure of (1) and (2) complexes was confirmed by single-crystal X-ray crystallography. It showed a distorted square planar geometry for both complexes around the metal center, and the H₂L adopt a bi-negative tridentate chelating mode. The interaction with biomolecules viz., calf thymus DNA (ct DNA), yeast RNA (tRNA), and BSA (bovine serum albumin) was examined by both UV-visible and fluorescence spectroscopies. The antioxidant activity of all compounds is discussed on basis of DPPH^• (2,2-diphenyl-1-picrylhydrazyl) scavenging activity and showed better antioxidant activity for complexes compared to the ligand. The in vitro cytotoxicity of the compounds was tested on human (breast cancer (MCF7), colon cancer (HCT116), liver cancer (HepG2), and normal lung fibroblast (WI38)) cell lines, showing that complex (1) the most potent against MCF7 and complex (4) against HCT116 cell lines based on IC₅₀ and selective indices (SI) values. So, both complexes were chosen for further studies such as DNA fragmentation, cell apoptosis, and cell cycle analyses. Complex (1) induced MCF7 cell death by cellular apoptosis and arrest cells at S phase. Complex (4) induced HCT116 cell death predominantly by cellular necrosis and arrested cell division at G2/M phase due to DNA damage.

Anti-glycemic potential of benzophenone thio/semicarbazone derivatives: synthesis, enzyme inhibition and ligand docking studies

Inhibition of dipeptidyl peptidase-IV (DPP-IV) has been identified as a promising approach for the treatment of type 2 diabetes mellitus (T2DM). Therefore, development of DPP-IV inhibitors with new chemical scaffold is of utmost importance to medicinal chemistry. In the present study, we identified benzophenone thio- and semicarbazone scaffolds as novel DPP-IV inhibitors. For that purpose, benzophenone thio- and semicarbazone were synthesized through a 2-step reaction. These newly synthetic derivatives were characterized by different spectroscopic techniques, including HREI-MS and NMR. whereas stereochemistry of the iminic bond was predicted by NOESY experiments. Thio- and semicarbazones derivatives were evaluated for their DPP-IV inhibitory potential and found to exhibit a good to moderate enzyme inhibitory activity. Most active and non-cytotoxic derivatives were further evaluated for their DPP-IV inhibitory potential in in cellulo model. The binding sites as well as affinity of active compounds for DPP- IV enzyme were predicted by in silico studies, and compared to a standard drug, sitagliptin. Pharmacophore studies of thio- and semicarbazones derivatives 1-29 suggest that substitution of aryl group, particularly a lipophilic substituents at C-4″ of benzene ring, and a hydroxyl at C-4' strongly influenced the DPP-IV inhibitory activity. Compound 9 showed the highest inhibitory activity (IC₅₀ = 15.0 ± 0.6 µM), whereas compounds 10, 17, 12, 14 and 23 showed a moderate activity with IC₅₀ values in the range of 28.9-39.2 µM. This study identifies thio- and semicarbazones as new classes of DPP-IV inhibitors which may translate into safe and effective therapeutics for a better management of type 2 diabetes.Communicated by Ramaswamy H. Sarma.

Binuclear Ni(II) complexes containing ONS donor Schiff base ligands: Preparation, spectral characterization, X-ray crystallography and biological exploration

Four binuclear Ni(II) complexes [[Ni₂(H-DEAsal-tsc)₂(μ-dppm)]·2Cl (1), [Ni₂(DEAsal-mtsc)₂(μ-dppm)] (2), [Ni₂(DEAsal-etsc)₂(μ-dppm)] (3) and [Ni₂(DEAsal-ptsc)₂(μ-dppm)] (4)] were synthesized from the ligands namely 4(N,N)-diethylaminosalicylaldehyde-4(N)-thiosemicarbazone [H₂-DEAsal-tsc] H₂L¹/4(N,N)-diethylaminosalicylaldehyde-4(N)-methyl thiosemicarbazone [H₂-DEAsal-mtsc] H₂L²/4(N,N)-diethylaminosalicylaldehyde-4(N)-ethyl thiosemicarbazone [H₂-DEAsal-etsc] H₂L³/4(N,N)diethylaminosalicylaldehyde-4(N)-phenyl thiosemicarbazone [H₂-DEAsal-ptsc] H₂L⁴ and 1,1'-bis(diphenylphosphino)methane (dppm) and characterized by a number of spectro analytical techniques. The molecular structure of complexes [Ni₂(H-DEAsal-tsc)₂(μ-dppm)]·2Cl (1) and [Ni₂(DEAsal-ptsc)₂(μ-dppm)] (4) have been confirmed by single crystal X-ray diffraction studies. The analysis indicated that in complex 1, the ligand [H₂-DEAsal-tsc] coordinated as monobasic tridentate donor through phenolic oxygen, azomethine nitrogen and thione sulfur atoms. However, in complex 4, the ligand [H₂-DEAsal-ptsc] behaved as dibasic tridentate donor with thiolate sulfur coordination. Their ability to bind with Calf Thymus Deoxyribonucleic acid (CT-DNA) and Bovine Serum Albumin (BSA) were analysed spectrometrically. Intercalative interaction of the complexes with DNA was confirmed by ethidium bromide (EB) displacement studies and DNA viscosity measurements. The interaction mechanism of the complexes with BSA was found as static. In vitro antiproliferative studies of the ligands and complexes in A549 (human lung carcinoma cancer), MCF-7 (human breast cancer) and HeLa (human cervical cancer) cell lines witnessed significant cytotoxic nature of the complexes with low IC₅₀ values (in μM) than the standard metallo-drug cisplatin. Further, the results of Lactate Dehydrogenase (LDH) and Nitric oxide (NO) release assays supported the effectiveness of the complexes on the above said cancer cells.

Efficient self-assembly of heterometallic triangular necklace with strong antibacterial activity

Sophisticated mechanically interlocked molecules (MIMs) with interesting structures, properties and applications have attracted great interest in the field of supramolecular chemistry. We herein report a highly efficient self-assembly of heterometallic triangular necklace 1 containing Cu and Pt metals with strong antibacterial activity. Single-crystal X-ray analysis shows that the finely arranged triangular necklace 1 has two racemic enantiomers in its solid state with intriguing packing motif. The superior antibacterial activity of necklace 1 against both standard and clinically drug-resistant pathogens implies that the presence of Cu(I) center and platinum(II) significantly enhance the bacterium-binding/damaging activity, which is mainly attributed to the highly positively charged nature, the possible synergistic effect of heterometals in the necklace, and the improved stability in culture media. This work clearly discloses the structure-property relationships that the existence of two different metal centers not only facilitates successful construction of heterometallic triangular necklace but also endows it with superior nuclease properties and antibacterial activities.

Precise assembly of heterometallic complexes is a challenge. Here, the authors design a heterometallic triangular necklace through a highly efficient threading-and-ring-closing approach driven by metal-ligand coordination, which shows strong bacterium-binding and cell wall/plasma membrane-disrupting capacity for killing bacterial cells.

Unprecedented formation of palladium(II)-pyrazole based thiourea from chromone thiosemicarbazone and [PdCl2(PPh3)2]: Interaction with biomolecules and apoptosis through mitochondrial signaling pathway

Two novel pyrazole based thiourea palladium(II) complexes, [PdCl(PPh₃)(C₉H₈NO₂S-pz)] (1) and [PdCl(PPh₃)(C₁₄H₁₀NO₂S-pz)] (2) [pz = pyrazole (C₃H₂N₂)] have been obtained unexpectedly from chromone thiosemicarbazones (L1 and L2) and [PdCl₂(PPh₃)₂]. The compounds have been fully characterized by physicochemical studies. The single crystal X-ray diffraction and spectral studies revealed square planar geometry for the complexes. The conversion of chromone thiosemicarbazone into pyrazole based thiourea might have happened through coordination to palladium(II) ion after enolization, Michael addition and ring opening followed by cyclization. To the best of our knowledge, this is the first report for the conversion of chromone thiosemicarbazone into pyrazole based thiourea moiety. Plausible mechanism was proposed based on the spectroscopic studies. Calf thymus (CT) DNA binding of the compounds was explored using various spectroscopic and molecular docking methods. DNA cleavage studies suggested that complexes 1 and 2 had the capacity to cleave the supercoiled DNA (pUC19) to its naked form. In vitro cytotoxic property of the ligands and complexes has been evaluated against three human cancer cells such as A549, HepG-2 and U937. Complex 2 exhibited potent cytotoxic activity against HepG-2 cells with the IC₅₀ value of 10.4 μM. In addition, mechanistic studies showed that complex 2 induced apoptosis through mitochondrial signaling pathway in HepG-2 cells. Beneficially, complex 2 showed less toxicity against human lung (IMR90) normal cells and hence it emerges as a potential candidate for further studies.

Synthesis, DNA/BSA binding studies and in vitro biological assay of nickel(II) complexes incorporating tridentate aroylhydrazone and triphenylphosphine ligands

Two new nickel (II) triphenylphosphine complexes derived from tridentate aroylhydrazone ligands [H2L1 = 2-hydroxy-3-methoxybenzylidene)benzohydrazone and H2L2 = N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazone] and triphenylphosphine were prepared and their molecular structures were determined by single crystal X-ray diffraction analysis. Both nickel(II) complexes showed slightly distorted square planar geometry with one tridentate aroylhydrazone ligand coordinated through ONO donor atoms and one triphenylphosphine ligand coordinated to the nickel center through the phosphorus atom. DNA interaction studies indicated that both complexes possessed higher affinity to herring sperm DNA (HS-DNA) than the corresponding free aroylhydrazone ligand. Molecular docking investigations showed that both complexes could bind to DNA through intercalation of the phenyl rings between adjacent base pairs in the double helix. Meanwhile, bovine serum albumin (BSA) binding studies revealed the complexes could effectively interact with BSA and change the secondary structure of BSA. Further pharmacological evaluations of the synthesized complexes by in vitro antioxidant assays demonstrated high antioxidant activity against NO· and O2˙- radicals. The anticancer activity of each complex was assessed through in vitro cytotoxicity assays (CCK-8 kit) toward A549 and MCF-7 cancer cell and normal L-02 cell lines. Significantly, the Ni(II) complex derived from H2L1 ligand was found to be more effective cytotoxic toward MCF-7cancerous cell with the IC50 value equaled 9.7 μM, which showed potent cytotoxic activity over standard drug cisplatin. AbbreviationsA549human lung carcinoma cellBSAbovine serum albuminCCK-8Cell Counting Kit-8DFTdensity functional theoryDNAdeoxyribonucleic acidDPPH˙2,2-diphenyl-1-picrylhydrazylH2L12-hydroxy-3-methoxybenzylidene)benzohydrazone N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazoneH2L2N'-(2-hydroxy-3-methoxybenzylidene)-2-hydroxybenzoylhydrazoneHOMOhighest occupied molecular orbitalIC50the 50% activityL-02human normal liver cellLOMOlowest unoccupied molecular orbital (LUMO)MCF-7human breast carcinoma cellNO˙nitric oxideO2˙-superoxide anionSODsuperoxide dismutaseCommunicated by Ramaswamy H. Sarma.

para metallation of 3-acetyl-chromen-2-one Schiff bases in tetranuclear palladacycles: focus on their biomolecular interaction and in vitro cytotoxicity

Three tetranuclear (1-3) complexes and a mononuclear (4) palladium(ii) complex were synthesized from 3-acetyl-chromen-2-one Schiff base ligands [H₂-3MAC-Rtsc] (where R = H [H₂-3MAC-tsc]; CH₃[H₂-3MAC-mtsc]; C₂H₅[H₂-3MAC-etsc] or C₆H₅[H₂-3MAC-ptsc]) and potassium tetrachloropalladate. Their formation was confirmed by spectroscopic techniques and X-ray crystallographic analysis. Their ability to bind with DNA and albumin was analysed by using absorption and emission titrations. The MTT assay was carried out to analyze the anticancer potential of the ligands and synthesized complexes against HepG2 (human liver cancer) and HT-29 (human colon cancer) cells. In addition, the compounds were less toxic when tested against the human normal keratinocyte cells (HaCaT). Ligands and complexes displayed better cytotoxicity with lower IC₅₀ values than the standard drug cisplatin. Further AO-EB and DAPI staining assays were carried out to detect the mode of cell death induced by the complexes i.e. apoptosis or necrosis. The complex 3 showed better cytotoxicity and was further subjected to flow cytometric analysis. The results suggested that the complex 3 induced apoptotic cell death.

Bioactivity of a radical scavenger bis(pyrazolium p-toluenesulphonate) on ctDNA and certain microbes: a combined experimental and theoretical analysis

A small organic molecule, bis(pyrazolium p-toluenesulphonate) (BPPTS), was crystallized, characterized and used to scavenge free radicals in biological systems. SXRD and spectroscopic analyses were used to confirm the structure of BPPTS. Methanolic and ethanolic solutions of BPPTS were used to assess the stability of the proposed drug using the UV-vis spectrophotometric technique. Optimization of the molecular structure was carried out by DFT with B3LYP/6-311++G(d,p) level of basis set. MEP and Fukui functions that elaborate theoretically the predominant electrophilic, nucleophilic and radical sites in BPPTS were correlated with experimental biological screening. BPPTS exhibits strong activity against Bacillus subtilis and Escherichia coli, comparable with all other analyzed pathogens. The free radical scavenging activity of BPPTS was assessed by both experimental studies and theoretical calculations. The binding sites of DPPH, which can bind to BPPTS, were also predicted by Fukui functions. DNA binding of BPPTS in UV-vis studies revealed the groove mode of binding due to the occurrence of hyperchromism. The phenomenon of hyperchromism was established by the Hirshfeld surface analysis of BPPTS, which confirmed the presence of π···π interactions (2.4%). Molecular docking established a positive correlation between experimental bio-screening reports and simulated data. ADMET properties were also calculated.

Distinct supramolecular assemblies of Fe(iii) and Ni(ii) complexes constructed from the o-vanillin salicylhydrazone ligand: syntheses, crystal structures, DNA/protein interaction, and antioxidant and cytotoxic activity

A novel aroylhydrazone ligand-bridged Ni(ii) coordination polymer was reported and its DNA binding, protein interaction, radical scavenging and in vitro anticancer properties were evaluated.

3-Acetyl-8-methoxy-2[H]-chromen-2-one derived Schiff bases as potent antiproliferative agents: Insight into the influence of 4(N)-substituents on the in vitro biological activity

A series of 3-acetyl-8-methoxycoumarin appended thiosemicarbazones (1-4) was prepared from the reaction of 3-acetyl-8-methoxycoumarin with 4(N)-substituted thiosemicarbazides in a view of ascertaining their biological properties with the change of N-terminal substitution in the thiosemicarbazide moiety. Comprehensive characterization was brought about by various spectral and analytical methods. The molecular structures of all the compounds were determined by single crystal X-ray diffraction analysis. Binding studies with Calf thymus DNA (CT-DNA) and proteins such as Bovine Serum Albumin (BSA) and Human Serum Albumin (HSA) indicated an intercalative mode of binding with DNA and static quenching mechanism with proteins. The compounds cleaved plasmid DNA (pBR322) and acted well as free radical scavengers. A good spectrum of antimicrobial activity was observed against four bacterial and five fungal pathogens. The compounds exhibited profound antiproliferative activity on MCF-7 (human breast cancer) and A549 (human lung carcinoma) cell lines. Assay on human normal keratinocyte cell line HaCaT showed that the compounds were non-toxic to normal cells.

Nickel(II) bis(isatin thiosemicarbazone) complexes induced apoptosis through mitochondrial signaling pathway and G0/G1 cell cycle arrest in IM-9 cells

Three novel complexes (1, 3 and 4) ligating N-substituted isatin thiosemicarbazone derivatives have been synthesized and their structural and biological characteristics have been compared with those of the known analogs (2, 5-7 and 8). In addition, the structure of the representative ligands (L1, L3 and L4) and complex (4) was confirmed by single crystal X-ray diffraction method. All the complexes (1-8) were assessed for their cytotoxic property against a panel of four human cancer cells such as HepG-2 (liver), MOLM-14 (acute monocytic leukemia), U937 (histiocytic lymphoma). and IM-9 (myeloma). Complex 4 exhibited prominent cytotoxic property against MOLM-14, U937 and IM-9 cell lines. Moreover, the results were compared with the well-known anticancer drugs like doxorubicin, cisplatin and daunorubicin. Besides, complex 4 enhanced the apoptotic cell death in IM-9 cell line and induced cell cycle arrest at G1 phase. Western blot analysis revealed the down-regulation of Bcl-2 (b-cell lymphoma-2), up-regulation of Bax (bcl-2 associated X protein), release of cytochrome c and activation of caspases-3 in IM-9 cells by complex 4. Importantly, complex 4 was not toxic to the normal Vero cell line (IC₅₀ > 300 μM). In addition, complex 4 showed the concentration dependent cleavage of supercoiled (SC) DNA to its nicked circular (NC) form.

Synthesis, spectroscopic, physicochemical and structural characterization of tetrandrine-based macrocycles functionalized with acridine and anthracene groups: DNA binding and anti-proliferative activity

In this work, we report on the synthesis of two new mono-alkylated tetrandrine derivatives with acridine and anthracene units, MAcT and MAnT. The compounds were fully characterized by physicochemical techniques and single-crystal X-ray diffraction analysis. In addition, both derivatives were studied as nucleotide receptors and double-stranded DNA binders in aqueous phosphate buffer at pH = 7.2 using UV-vis and fluorescence spectroscopy. According to the molecular recognition studies, MAcT and MAnT exhibit high affinity (K ∼ 10⁵ M^-1) and selectivity for ds-DNA, presumably in an intercalation mode. Finally, the anti-proliferative effects of the tetrandrine derivatives on different cancer cell lines were explored, revealing promising activities. Particularly, the mono-anthracene tetrandrine derivative MAnT showed an IC₅₀ of 2.74 μg/mL on the HeLa cervical cancer cell line, representing a value 3.3 times smaller than that obtained for unsubstituted tetrandrine. Examination of the cytotoxic effects on the HeLa cell line by inverted microscopy suggests that the cell death mechanism consists basically in apoptosis. The molecular modelling of three ds-DNA-MAcT complexes, suggested that the macrocycles may use an intercalation binding mode towards DNA. MAcT is predicted to bind into the major groove of the ds-DNA providing non-covalent interactions such as electrostatic, van der Waals and hydrophobic interactions that lead to selectivity. Overall experimental data supports the mode of action of MAnT and MAcT as cytotoxic compounds against cancer cell lines via a DNA interaction mechanism.

Cyclometallated ruthenium(ii) complexes with 3-acetyl-2[H]-chromene-2-one derived CNS chelating ligand systems: synthesis, X-ray characterization and biological evaluation

The presented work focuses on the synthesis and biological evaluation of 3-acetylcoumarin Schiff bases and their cyclometallated ruthenium(ii) metallates.

Pentavalent phosphorus as a unique phosphorus donor in POCl3 homodimer and POCl3–H2O heterodimer: matrix isolation infrared spectroscopic and computational studies

Phosphorus, an important element among the pnicogen group, opens up avenues for experimental and computational explorations of its interaction in a variety of compounds.

Synthesis, structures and mechanistic pathways of anticancer activity of palladium(ii) complexes with indole-3-carbaldehyde thiosemicarbazones

Palladium(ii) complexes featuring bidentate heterocyclic thiosemicarbazones have been synthesized, characterized and evaluated for their biomolecular interactions. The complexes induced in vitro anticancer activity through apoptosis.

An investigation on 3-acetyl-7-methoxy-coumarin Schiff bases and their Ru(ii) metallates with potent antiproliferative activity and enhanced LDH and NO release

New cyclometallated ruthenium(ii) complexes of 3-acetyl-7-methoxycoumarin-4N-substituted thiosemicarbazones were synthesized and characterized by analytical and spectral techniques.