BSA Binding Studies Research Articles

Metal complexes containing vitamin B6-based scaffold as potential DNA/BSA-binding agents inducing apoptosis in hepatocarcinoma (HepG2) cells.

A ligand (HL) was synthesized from the pyridoxal hydrochloride (vitamin B6 form) and 1-(2-Aminoethyl)piperidine in one single step. The metal complexes [Zn(L)(Bpy)]NO3 (1), [Cu(L)(Bpy)]NO3 (2), and [Co(L)(Bpy)]NO3 (3) were prepared by tethering HL and 2,2'-bipyridine. The synthesized HL and metal complexes 1-3 were thoroughly characterized using spectroscopic techniques such as 1H NMR, 13C NMR, FTIR, EI-MS, molar conductance, and magnetic moment, in addition to CHN elemental analysis. The geometry of complexes was square pyramidal around the metal ions {Zn(II), Cu(II), and Co(II)}. The interaction of ligand and metal complexes with DNA and BSA macromolecules was accomplished by UV-Vis absorption and fluorescence spectroscopy in vitro. The hyperchromism in band at 303-325 with no shift supports the groove binding with some partial intercalation in grooves. Similarly, in BSA-binding studies, complex 2 shows greater binding potential in the hydrophobic core probably near the Trp-212 in the subdomain IIA. Furthermore, complex 2 shows excellent cytotoxicity on HepG2 cancer cells with IC50 = 25.0 ± 0.45µM. The detailed analysis by cell-cycle studies shows cell arrest at the G2/M phase. The type of cell death was authenticated by an annexin V-FTIC dual staining experiment that reveals maximum death by apoptosis together with non-specific necrosis.

Synthesis and Characterization of Metal Complexes [M(L)(Im)]NO3, In Vitro DNA/BSA Binding Behavior and Cytotoxicity on HepG2 Cancer Cells

AbstractA new ligand (HL) was prepared from heterocyclic 8‐Hydroxy‐2‐quinolinecarboxaldehyde and 2‐Aminobenzophenone in one pot synthesis. The metal complexes of the types [Zn(L)(Im)]NO3 (1), [Cu(L)(Im)]NO3 (2) and [Co(L)(Im)]NO3 (3) were prepared by adopting HL and Imidazole under refluxing conditions. The HL and complexes 1–3, were characterized by CHN elemental analysis and spectroscopic methods 1H NMR, 13C NMR, FT‐IR, ToF Mass. The spectroscopic studies suggest square pyramidal geometry in all complexes. The interaction of ligand and complexes with DNA and BSA was conducted by UV‐vis absorption and fluorescence spectroscopy. The Kb value of 2.17×104 M−1 for complex 2 is the highest depicting its greater binding propensity with DNA. Similarly, in BSA binding studies, complex 2 shows greater binding potential in the hydrophobic core probably near the Trp 212 in the subdomain IIA. Furthermore, the complex 2 shows excellent cytotoxicity on HepG2 cancer cells with IC50=74.05±0.69 μM. In the cell cycle analysis of HepG2 cells, it has been observed that complex 2 arrests the cell proliferation in the G1/S phase. Annexin V‐based flow cytometry analysis further indicated 6‐fold apoptotic cell death by complex 2 in the experiment along with non‐specific necrosis cell death.

Binuclear palladacycles with ionisable and non-ionisable tethers as anticancer agents

The search for novel anticancer agents to replace the current platinum-based treatments remains an ongoing process. Palladacycles have shown excellent promise as demonstrated by our previous work which yielded BTC2, a binuclear palladadycle with a non-ionisable polyethylene glycol (PEG) tether. Here, we explore the importance of the PEG-tether length on the anticancer activity of the binuclear palladacycles by comparing three analogous binuclear palladacycles, BTC2, BTC5 and BTC6, in the oestrogen receptor positive MCF7 and triple-negative MDA-MB-231 breast cancer cell lines. In addition, these are compared to another analogue with an ionisable morpholine tether, BTC7. Potent anticancer activity was revealed through cell viability studies (MTT assays) revealed that while BTC6 showed similar potent anticancer activity as BTC2, it was less toxic towards non-cancerous cell lines. Interestingly, BTC7 and BTCF were less potent than the PEGylated palladacycles but showed significantly improved selectivity towards the triple-negative breast cancer cells. Cell death analysis showed that BTC7 and BTCF significantly induced apoptosis in both the cancer cell lines while the PEGylated complexes induced both apoptosis and secondary necrosis. Furthermore, experimental and computational DNA binding studies indicated partial intercalation and groove binding as the modes of action for the PEGylated palladacycles. Similarly, experimental and computational BSA binding studies indicated and specific binding sites in BSA dependent on the nature of the tethers on the complexes.

Copper-mediated cyclization of thiosemicarbazones leading to 1,3,4-thiadiazoles: Structural elucidation, DFT calculations, in vitro biological evaluation and in silico evaluation studies

Cancer's global impact necessitates innovative and less toxic treatments. Thiosemicarbazones (TSCs), adaptable metal chelators, offer such potential. In this study, we have synthesized N (4)-substituted heterocyclic TSCs from syringaldehyde (TSL1, TSL2), and also report the unexpected copper-mediated cyclization of the TSCs to form thiadiazoles (TSL3, TSL4), expanding research avenues. This work includes extensive characterization and studies such as DNA/protein binding, molecular docking, and theoretical analyses to demonstrate the potential of the as-prepared TSCs and thiadiazoles against different cancer cells. The DFT results depict that the thiadiazoles exhibit greater structural stability and reduced reactivity compared to the corresponding TSCs. The docking results suggest superior EGFR inhibition for TSL3 with a binding constant value of − 6.99 Kcal/mol. According to molecular dynamics studies, the TSL3-EGFR complex exhibits a lower average RMSD (1.39 nm) as compared to the TSL1-EGFR complex (3.29 nm) suggesting that both the thiadiazole and thiosemicarbazone examined here can be good inhibitors of EGFR protein, also that TSL3 can inhibit EGFR better than TSL1. ADME analysis indicates drug-likeness and oral availability of the thiadiazole-based drugs. The DNA binding experiment through absorption and emission spectroscopy discovered that TSL3 is more active towards DNA which is quantitatively calculated with a Kb value of 4.74 × 106 M−1, Kq value of 4.04 × 104 M−1and Kapp value of 5 × 106 M−1. Furthermore, the BSA binding studies carried out with fluorescence spectroscopy showed that TSL3 shows better binding capacity (1.64 × 105 M−1) with BSA protein. All the compounds show significant cytotoxicity against A459-lung, MCF-7-breast, and HepG2-liver cancer cell lines; TSL3 exhibits the best cytotoxicity, albeit less effective than cisplatin. Thiadiazoles demonstrate greater cytotoxicity than the TSCs. Overall, the promise of TSCs and thiadiazoles in cancer research is highlighted by this study. Furthermore, it unveils unexpected copper-mediated cyclization of the TSCs to thiadiazoles.

1‐Benzyl‐1H‐indazol‐3‐ol Copper(II) Derivatives as Anticancer Agents: In‐vitro Interaction with DNA/BSA, DFT, Molecular Docking and Cytotoxicity on MCF7 Cells

AbstractA set of three copper(II) complexes C28H24CuN4O2 [CuL1], C24H22CuN4O [CuL2] and C26H22CuN4O [CuL3] incorporated with ligands 1‐benzyl‐1H‐indazol‐3‐ol, 2,2′‐bipyridyl and 1,10‐phenanthroline have been synthesized, characterized and subjected for biomedical applications. New copper(II) derivatives were characterized by FTIR, EPR and HRMS spectral tools. Cyclic voltammograms were recorded to ascertain redox potential and UV‐Vis and Fluorometer were employed to establish photophysical properties of all the new copper(II) complexes. Further, these derivatives of Cu(II) were subjected for DNA and BSA binding studies by using absorption‐emission spectral methods and viscosity measurements as well as by molecular docking. DFT studies of the above‐mentioned derivatives suggested square planar geometry along with other relevant molecular investigations. Eventually, these new Cu(II) complexes have been tested with DPPH and MTT assay to determine the cytotoxicity against MCF7 cell lines to observe remarkable potency with IC50 values 80.68 μg/ml, 49.40 μg/ml and 45.91 μg/ml, respectively.

New 1,2,3-triazoles and their oxime derivatives: AChE/BChE enzyme inhibitory and DNA binding properties

1,2,3-Triazole compounds (1a–3a) and their oxime derivatives (1b–3b) were synthesized. The structures of these synthesized compounds were characterized using common spectroscopic methods. Crystal structures of the compounds 3, 2b and 3b were determined by single crystal X-ray diffraction studies. The acetylcholinesteras (AChE) and butyrylcholinesterase (BChE) cholinesterase inhibitor (ChEI) and DNA/calf serum albumin (BSA) binding properties of the compounds were examined. DNA binding studies have shown that compounds interact with DNA through 1,2,3-triazole and oxime groups. When the binding constant K b values were compared, it was revealed that compound 3b (K b = 4.6 × 105 M−1) with oxime in its structure binds more strongly than the others. In addition, in vitro BSA binding studies showed that compounds 1b and 3b exhibited higher binding affinity. These results confirm that the quenching is due to the formation of a compound resulting from the static quenching mechanism, rather than being initiated by a dynamic mechanism. Likewise, when the enzyme activity of the compounds was examined, the compounds exhibited high inhibitory activity against AChE. The highest activity was observed for compounds 2b and 3b (8.6 ± 0.05 and 4.8 ± 0.052 µM). It was observed that the compounds were not selective with respect to BChE. Communicated by Ramaswamy H. Sarma

Quinoxaline-derived “turn-off” fluorescent sensor for the selective detection of Fe3+: Synthesis, spectroscopic analysis, BSA binding and computational studies

A simple quinoxaline-based “turn-off” fluorescent sensor 12-{[1-(4-isopropylphenyl)-1H-1,2,3-triazol-5-yl]methyl}c-12H-benzo[5,6][1,4]thiazino[2,3-b]quinoxaline (BTQT) was synthesised and characterised by various spectroscopic technique including FT-IR, 1D, 2D NMR and mass spectrometry. DFT-based studies have been employed to calculate reactivity descriptor-associated with the molecular structure. UV–visible absorption and fluorescence spectral studies revealed a selective “turn-off” fluorescent response towards Fe3+ with a detection limit of 3.5 µM and a response time of 5 s. Job's plot and mass spectrum establish 1:1 binidng stoichiometry between Fe3+ and BTQT. Spectral studies revealed a static mode of BTQT binding with bovine serum albumin accompanied by hydrogen bonding and weak van der Waals force of interactions. The experimental results of BSA binding were further supported by in silico studies and are in good corroboration with the experimental findings. Such a convenient and simple methodology could impart an auspicious tool for rapid, selective and sensitive analysis of Fe3+ and BSA.

Copper(II)/diiminic complexes based on 2-hydroxybenzophenones: DNA- and BSA-binding studies and antitumor activity against HCT116 and HepG2 tumor cells

Here, we report four new heteroleptic Cu(II) complexes with the formula [Cu(bipy)(2H4MeBz)]NO3 (1), [Cu(phen)(2H4MeBz)]NO3 (2), [Cu(bipy)(2H4OcBz)]NO3 (3) and [Cu(phen)(2H4OcBz)]NO3 (4), where the ligands are 2-hydroxy-4-methoxybenzophenone (2H4MeBz), 2-hydroxy-4-(octyloxy)benzophenone (2H4OcBz), 2,2′-bipiridine (bipy) and 1,10-phenantroline (phen). All compounds present two bidentate ligands, a monoanionic 2-hydroxybenzophenone, forming a six-membered chelate ring and the diiminic ring forming a five-membered chelate ring, as well as one nitrate as counterion located at the axial position, as suggested by the crystal structure of complex 2. Complex/DNA interaction studies were also performed using spectroscopic titration (Kb close to 104 M−1), viscosity, Hoechst 33258 competition, and circular dichroism, revealing a moderate interaction between them. Additionally, complexes 1–4 moderately interact with BSA (Bovine Serum Albumin). The compounds were evaluated against HCT116 (human colon carcinoma) and HepG2 (human hepatocellular carcinoma) cancer cells and against MRC-5 (human lung fibroblast), a noncancer cells. The cytotoxic results suggest that complexes 2 and 4 are more cytotoxic than 1 and 3, showing that the presence of phen ligand may play an important role in increasing the biological effect of the compounds.

Synthesis and characterization of N4-substituted thiosemicarbazones: DNA/BSA binding, molecular docking, anticancer activity, ADME study and computational investigations

A series of thiosemicarbazones with the general formula, R−CHN−NH−C(S)−R1 [R = C6H5F & R1= C4H9NO (TL1), R = C8H10O2 & R1= C4H9NO (TL2), R = C6H5F & R1= C4H9N (TL3), R = C6H5Br & R1= C4H9N (TL4)] were synthesized. The UV–Visible, Infra-red, NMR and HRMS spectra were used to confirm compounds. The single-crystal X-ray diffraction (XRD) technique was used to determine the molecular composition of TL3 and TL4. Absorption/emission spectroscopic titrations were subjected to evaluate the compounds' interactions with Calf-Thymus (CT) DNA. According to DNA binding research findings, the compounds were bound to DNA in an interactive manner, as evidenced by the hypochromic and slight red shift. The compound TL3 possesses a high binding constant (5.17 × 106 M−1), which indicates that it bound CT-DNA more firmly than other compounds. The red shift and strong hypochromic shift observed in the fluorescence titration spectrum of BSA binding studies described a strong interaction of compounds with BSA. The compound TL3 exhibits a redshift of 3 nm and 92% quenching. The BSA protein docking studies of the compounds revealed their ability to act as medicines for the targets. Amongst the four compounds, TL3 shows high binding energy towards BSA ( ̶ 6.33 Kcal/mol) protein. B3LYP/ 6–311 G (d, p) level theories were used to compute density functional theory (DFT). Computational evaluations of the generated compounds show that the compound TL2 has significantly higher structural stability than other compounds. According to SwissADME studies, the LogP values for all compounds were less than 5, indicating appropriate lipophilicity characteristics. The low degree of synthetic accessibility ranges from 2–3, indicating a quality result for this characteristic. In other words, all the compounds TL1-TL4 have the potential to evolve into good oral drug candidates. Anticancer activity of four compounds (TL1-TL4) was investigated on human HepG-2-liver, EAhy-926-endothelial carcinoma cancer and African green monkey normal Vero cells. The compound TL3 showed good activity in liver and endothelial carcinoma cancer cells with IC50 values of 37.5 and 30.1 µM, respectively.

Synthesis, characterization and biological evaluation of piperazine embedded copper complexes

In this paper, we report the synthesis, and characterization of three piperazine based multidentate ligands and their copper complexes. Ligands and complexes were characterized by UV–Vis, FT–IR, 1H NMR and mass spectra along with EPR spectra, molar conductance and thermogravimetric analysis (TGA). The metal complexes showed peaks corresponding to ligand to Cu(II) LMCT transition in UV–Vis spectrum. Molar conductance values of all complexes studied in water and DMSO indicated nonionic nature of complexes. TGA derivative curve represented the initial loss of water, which was in agreement of coordinated water in the proposed complexes. Four coordinated copper complexes were proposed on the basis of spectral data and supported by mass fragmentation pattern, isotopic distribution pattern, EPR, molar conductance and TGA. Ligands and complex geometries were optimized using DFT calculations and TDDFT studies of ligands were performed to corroborate the experimental UV–Vis spectrum. These ligands and complexes were tested for antibacterial activity and all complexes showed higher activity as compared to ligands. Antioxidant behavior of complexes was investigated by DPPH (2,2-diphenyl-1-picrylhydrazyl) method, and percentage inhibition data suggested two complexes Cu2L1 and Cu2L3 to hold fair antioxidant potential. In vitro cytotoxic studies of complexes performed on breast cancer cell line (MCF–7) using MTT calorimetric assay and IC50 value indicated good cytotoxic potential. BSA binding studies and DNA binding studies with CT-DNA were performed using UV–Vis titrimetric methods and were supported by molecular docking studies of complexes to investigate available binding interactions sites.

Structural elucidation of new ferrocene appended scaffold and their metal complexes: Comparative in vitro DNA/BSA binding and antibacterial assay

A new organometallic ligand (L) was designed and synthesized from ferrocenecarboxaldehyde and 2–Aminobenzophenone through the condensation reaction in one step process. The metal complexes of this L with the formula [Zn(L)2](NO3)2 (1), [Cu(L)2](NO3)2 (2) and [Co(L)2](NO3)2 (3) were synthesized in high yield. The ligand (L) and complexes 1–3 were completely characterized by elemental analysis, spectroscopic and spectrometric techniques such as FT–IR, ToF Mass,1H NMR,13C NMR molar conductance and magnetic moment measurements. The spectroscopic interpretation showed that complex 1 and complex 3 prefer tetrahedral geometry whereas complex 2 adopts a square planar arrangement around the copper(II) ion. The in vitro DNA interaction studies of ligand (L) and metal complexes 1–3, were performed by UV–Vis absorption, fluorescence spectral and ethidium bromide displacement experiments. The absorption studies of complexes 1–3 reveal the existence of both hyperchromic and hypochromic effect which indicated the mixed type of binding that is intercalation of the aromatic part and the electrostatic surface interaction of metal ions with DNA phosphate groups. A comparison of binding constant Kb values suggested the stronger binding of complex 2 (Kb = 6.17 × 104 M−1) as compared to L and complexes 1 and 3. Furthermore, in vitro BSA binding studies and FRET also suggests greater interaction of complex 2 with BSA causing modulations in the hydrophobic microenvironment near Trp-212 in the subdomain IIA pocket by static quenching mechanism. Interestingly, all three complexes 1–3 tested showed promising antimicrobial activity as revealed by the disc diffusion assay in all four human pathogenic bacterial species comprising both gram–positive and gram–negative bacteria.

In vitro biological assessment of 1,3,4-oxadiazole sandwiched by azinane and acetamides supported by molecular docking and BSA binding studies

The 1,3,4-Oxadiazole is an aromatic heterocyclic moiety recognized in drug research for its low lipophilicity. The multiple functionalities, heterocyclic azinane, sulfonamide, 1,3,4-oxadiazole and acetamide, are combined collectively to enhance the bioactivity potential of synthesized molecules. All the compounds were acquired by following microwave assisted and conventional techniques in a comparative way. The synthesized derivatives were screened for their antibacterial and enzyme inhibition potential. Furthermore, BSA binding analysis was executed to infer about the interaction with serum albumin. The spectral data of IR, EI-MS, 1H-NMR and 13C-NMR were used to elucidate the final structures of compounds. The synthesized compounds had a modest antibacterial potential. Compound 8f bearing 2-methyl-4,5-dinitrophenyl group was the most active one against all the bacterial strains taken into account and α-glucosidase enzyme. Compound 8d bearing 4-nitrophenyl group was the best acetyl cholinesterase inhibitor and 8i bearing phenylethyl group was the best urease inhibitor.

A novel series of tetrahydrothieno[2,3-c]pyridin-2-yl derivatives: fluorescence spectroscopy and BSA binding, ADMET properties, molecular docking, and DFT studies

A series of substituted tetrahydrothieno[2,3-c]pyridin-2-yl (THTP) derivatives were synthesized in one step using 2-amino-5,5,7,7-tetramethyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carbonitrile with chloro- and nitro-groups.

Exploration of structural, electrostatic and photophysical behaviour of novel Ni(II), Cu(II) and Zn(II) complexes and their utility as potent antimicrobial agents

In the present manuscript, a series of Ni(II), Cu(II) and Zn(II) based metal complexes were synthesized, and their molecular geometry was established using single‐crystal X‐ray diffraction studies. The surface characteristic along with the presence of various intermolecular interactions was quantified using crystal explorer. The atom‐based contribution of various molecular interactions in the overall interactions was evaluated by the decomposition of Hirshfeld surfaces into a 2D fingerprint region. DFT‐based global reactivity descriptors were calculated to gain an idea about the chemical reactivity and stability. A reduction in the energy gap on complexation along with a red shift in the absorption spectra confirms the formation of metal complexes. The presence of a small energy gap in case of Cu(II) complex reflects the presence of an efficient electronic charge transfer mechanism in this case. The photophysical properties of L2 and its metal complexes were also evaluated in different solvents. A maximum stoke shift of 6234.51 cm−1 was exhibited by M2D when its spectra were recorded in MeOH. The bio‐efficacy of L2 and its metal complexes (M2A, M2C and M2D) were evaluated using in vitro anti‐microbial assays. Maximum inhibition of both bacterial and fungal growth was exhibited by M2A with an MIC value of 32 μg mL−1 against B. cereus, X. campestris, and C. albicans. The fluorescence‐based approach was used to conduct BSA binding studies with all three metal complexes. The presence of a positive entropy change (S) value implies that protein‐ligand binding is entropy‐driven by hydrophobic interactions. Finally, in silico molecular docking and dynamics investigations were carried out to explore the most probable mode of C. albicans inhibition.

Synthesis and characterization of copper complexes of phenylpiperazine ring-based ligands and evaluation of their antimicrobial, BSA binding, computational, and molecular docking studies

This paper describes the synthesise of copper complexes of phenylpiperazine ring-based ligands and characterization via physical and spectroscopic methods. Structure of complexes has been proposed on the basis of UV-vis, IR and Mass fragmentation pattern and additionally supported by electrochemical and thermogravimetric analysis. Low molar conductance value of metal complexes in water and DMSO suggest non-ionic nature of complexes which is in agreement of proposed structure. TGA curve, where loss of coordinated solvent molecules starts early followed by loss of ligand itself also support the proposed structures. Percentage ash content analysis also indicate that only one copper metal is binding to the ligands reported here. Antibacterial activity of metal complexes has been performed by agar well diffusion method and indicated these metal complexes possess higher activity than the corresponding ligands. Binding interaction of these complexes were studied with BSA protein by UV-vis spectroscopic methods and binding constant was calculated which indicated that the complexes are having moderate affinity. Some complexes were also geometrically optimized to lowest energy ground state by using DFT calculations. Docking study of these optimized structures with BSA protein revealed these metal complexes exhibit hydrophobic interaction owing to the aromatic bulk in the ligand.

Fluorinated N-quinoxaline-based boron complexes: Synthesis, photophysical properties, and selective DNA/BSA biointeraction

A series of six examples of 1,1-difluoro-3,5-diaryl-1H [1,2,3,5] oxadiazaborinino[3,4-a]quinoxalin-11-ium-1-uides as a new N-quinoxaline-based boron complex with variable structures was synthesized at 65–70% yields from the reaction of the respective N-(3-arylquinoxalin-2-yl)benzamides with BF3·Et2O — in which aryl = phenyl, 4-ClC6H4, 4-CH3C6H4, and 4-NMe2C6H4. All new benzamides and BF2-complexes were fully characterized by 1H-, 13C, 19F-, and 11B-NMR spectroscopy and single-crystal X-ray diffraction. Moreover, the photophysical properties, TD-DFT analysis, DNA and BSA-binding experiments, and molecular docking studies for these new organoboron complexes were studied. The new BF2-heterocycles demonstrated to be weak generators of 1O2, although their solutions at 5.0 µM showed great photostability over the investigated irradiation. Additionally, the results of the DNA and BSA-binding studies indicated that the greatest interactions were selective in the minor groove of DNA and by the tryptophan site in the BSA albumin pocket.

Synthesis, Crystal Studies, Dft Calculations, Antimicrobial Activity and Bsa Binding Studies of Metal Complexes Derived from Pyridyl-Based Hydrazone

Synthesis, Crystal Studies, Dft Calculations, Antimicrobial Activity and Bsa Binding Studies of Metal Complexes Derived from Pyridyl-Based Hydrazone

Synthesis, structural characterization, in vitro comparative DNA/RNA binding, and computational studies of half-sandwich Ru (II)(ƞ6-p-cymene) aminoquinoline complex

We describe herein, synthesis of a half-sandwich Ru (II)(ƞ6-p-cymene) complex 1 containing aminoquinoline ligand. Complex 1 was characterized by various spectroscopic and single-crystal X-ray crystallographic techniques. The “piano-stool” complex crystallizes in a triclinic P1¯ space group with ruthenium (Ⅱ)(p-cymene) fragment tethered to a primary amine nitrogen atom of aminoquinoline. DFT calculations were performed to generate UV and IR spectra of complex 1 which further supported the experimental data. Comparative DNA/RNA binding studies of the complex were carried out by employing UV–vis, fluorescence, circular dichroism, and cyclic voltammetric techniques. The intrinsic binding constants of the complex 1 with ct-DNA and tRNA were calculated to be 3.9 × 105 (±0.09) M−1 and 2.45 × 104 (±0.10) M−1 which indicated a stronger binding affinity of the complex 1 towards ct-DNA. The pBR322 plasmid scissoring efficiency of the complex was explored by performing gel electrophoresis. The results suggested that the complex induced double-stranded DNA cleavage at 35 μM concentration which is mediated via an oxidative pathway. RNA gel fragmentation assay was also performed in both concentration and time-dependent manner and an appreciable reduction in the intensity of the bands was observed after 24 hr incubation which demonstrated complete cleavage of the tRNA. BSA and lysozyme binding studies of the complex were also carried out and the results revealed that complex 1 quenched the fluorescence intensity of the proteins. Cytotoxicity studies revealed low cytotoxicity against three human cancer cell lines. Furthermore, molecular modeling approach was applied to probe the binding-conformation of the complex with ct-DNA/tRNA and the results showed that complex 1 exhibited preferential binding propensity towards ct-DNA.

Heterodinuclear Cu–Gd (3d-4f) complex with di-compartmental Schiff base ligand in biological activity: Synthesis, crystal structure, catecholase activity and DNA & BSA-binding studies

A dinuclear CuII-GdIII Schiff base complex (a di-compartmental Schiff base ligand derived from o-vanillin) nominated as: 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol) (H2valpn) was synthesized in two steps. To characterize the compounds, single-crystal X-ray crystallography, UV–Vis spectroscopy, IR spectroscopy, and elemental analyses were used. The crystalline sample of the heterodinuclear complex revealed the structure of general formula [(valpn) (H2O) CuII GdIII (NO3)3], with the copper ion located in a square pyramidal section (with an axial aqua ligand) and the gadolinium (III) ion located in the open compartment, in which 10 oxygen atoms from three chelating nitrate ions and a Schiff base ligand surrounded it. To study the applications of the complex, the binding affinity of the complex with FS-DNA was studied by UV–Vis spectroscopy, fluorescence spectroscopy, viscosity measurements, cyclic voltammetry (CV) and circular dichroism (CD). From all of these methods, intercalation was suggested as the main mode of binding. The complex was also checked in interaction with Bovine serum albumin (BSA) by using UV–Vis and fluorescence spectroscopy. Cytotoxicity was tested by MTT assay toward HeLa, LNCaP, and MCF-7 cancer cell lines. Moreover, the docking calculation was performed and these results confirmed the experimental results. The mechanism and kinetics of the catalytic activity of the complex in the oxidation reaction of 3,5-di-tert-butylcatechol, was studied at 298 K.

Synthesis, characterization, DNA/BSA binding and cytotoxicity studies of Mononuclear Cu(II) and V(IV) complexes of Mannich bases derived from Lawsone

A series of new mononuclear copper complexes (1–5) and a vanadium complex (6) were synthesized using bidentate Mannich base ligands derived from bioactive molecule Lawsone. The structure of these new molecules/complexes (1–6) were characterized by various spectroscopic techniques such as UV-Vis, FT-IR, EPR, and ESI-MS. The structure of complex 1 was also confirmed by single crystal X-ray diffraction analysis, which revealed that complexes containing copper atom has slightly distorted square planar geometry. Computational studies were carried out for the synthesized compounds (1–6) using the DFT method with B3LYP/6–311 G (d, p) and LanL2DZ basis sets to assess the bond length, bond angle, HOMO, and LUMO energy gap (∆E). The CT-DNA and BSA binding (protein binding affinity) studies revealed that complex 4 exhibited the highest DNA binding affinity and complexes 5 and 6 exhibited the highest protein binding affinity. The cytotoxic activity of complexes 3–6 was evaluated using MTT assay along with the apoptosis assessment (AO/EB staining) against HepG2 (human liver carcinoma cell line). Furthermore, the data revealed that all the complexes 3–6 displayed very good anticancer activity with IC50 values in the range of 5.46–2.71 µM which is comparable with that of standard anticancer drug.