DNA interaction, antimicrobial, antioxidant and anticancer studies on Cu(II) complexes of Luotonin A

Among the bio‐metals, copper derivatives of O, N, S donor salicylaldehyde thiosemicarbazones have been obtained large interest due to their potential biological applications. Multisubstituted thiosemicarbazone ligand HL derived, new ternary Cu (II) complexes of [Cu(L)(bpy)] (1) and [Cu(L)(phen)] (2) (where, bpy is 2,2′‐bipyridine and phen is 1,10‐phenanthroline) have been synthesized and characterized using different physico‐chemical techniques. Complexes 1 and 2 are structurally characterized by single crystal X‐ray diffraction analysis, which reveals the trigonal bipyramidal distorted square based pyramid geometry of both the complexes 1 and 2 with ONS‐donor thiosemicarbazone bonded at the upper plane. The ground state electronic structures of complexes 1 and 2 have been investigated by using DFT/B3LYP theoretical evaluation with 6‐31G (d,p) and LANL2DZ basis set. The affinity towards DNA and human serum albumin has been evaluated using computational docking analysis and complex 2 exposes significant binding ability towards DNA and human serum albumin, because of its immense hydrophobicity. Consequently, complex 2 have higher antimicrobial in addition to the cytotoxic activity than complex 1 and free ligand HL under visible light. Along with, their apoptosis pathway of cytotoxicity has been evaluated by fluorescent microscopic analysis using acridine orange/ethidium bromide (AO/EB) stains. From these preliminary investigations, we believe that complex 2 can play a role as a more robust pharmacological agent.

Section: Resultsmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Ternary Copper (II) complex based chemical probes for DNA targeting: Cytotoxic activity under visible light

Shanmugaiah¹,

Palsamy²,

Ravi

et al. 2018

“…The complex 2 has the value of g ║ = 2.318 in conformity with the presence of both Cu–O and Cu–N bonds. The quotient (g ║/ A ║ ), which is empirically treated as a measure of the distortion from planarity, has been found to be 186 and 164 cm −1 for the complexes 1 and 2 , respectively indicating distortion from a square planar structure to a deformed tetrahedral structure …”

Section: Resultsmentioning

confidence: 99%

New anthracene based Schiff base ligands appended Cu(II) complexes: Theoretical study, DNA binding and cleavage activities

Gubendran

Kumar²,

Kesavan³

et al. 2017

New anthracene based Schiff base ligands L1 and H(L2), their Cu(II) complexes [Cu(L1)Cl2] (1) and [Cu(L2)Cl] (2), (where L1 = N1,N2‐bis(anthracene‐9‐methylene)benzene‐1,2‐diamine, L2 = (2Z,4E)‐4‐(2‐(anthracen‐9‐ylmethyleneamino)phenylimino)pent‐2‐en‐2‐ol) have been prepared and characterized by elemental analysis, NMR, FAB‐mass, EPR, FT‐IR, UV–Vis and cyclic voltammetry. The electronic structures and geometrical parameters of complexes 1 and 2 were analyzed by the theoretical B3LYP/DFT method. The interaction of these complexes 1 and 2 with CT‐DNA has been explored by using absorption, cyclic voltammetric and CD spectral studies. From the electronic absorption spectral studies, it was found that the DNA binding constants of complexes 1 and 2 are 8.7 × 103 and 7.0 × 104 M−1, respectively. From electrochemical studies, the ratio of DNA binding constants K+/K2+ for 2 has been estimated to be >1. The high binding constant values, K+/K2+ ratios more than unity and positive shift of voltammetric E1/2 value on titration with DNA for complex 2 suggest that they bind more avidly with DNA than complex 1. The inability to affect the conformational changes of DNA in the CD spectrum is the definite evidences of electrostatic binding by the complex 1. It can be assumed that it is the bulky anthracene unit which sterically inhibits these complexes 1 and 2 from intercalation and thereby remains in the groove or electrostatic. The complex 2 hardly cleaves supercoiled pUC18 plasmid DNA in the presence of hydrogen peroxide. The results suggest that complex 2 bind to DNA through minor groove binding.

“…The cytotoxicity studies of Schiff base ligand HL and its metal (II) complexes 1–3 are analyzed by the MTT assay strategy against Human breast cancer cells (MCF‐7 cells) . The characteristic morphological changes of AO/EB‐stained cancer cells treated with Schiff base ligand HL and its metal (II) complexes 1–3 have been evaluated by using fluorescent microscopy.…”

Section: Methodsmentioning

confidence: 99%

Biomolecular docking, antimicrobial and cytotoxic studies on new bidentate schiff base ligand derived metal (II) complexes

Chandrasekhar

Kesavan²,

Ravi

et al. 2018

Three new metal complexes [Cu(L)2] (1), [Co(L)2] (2) and [Zn(L)2] (3) have been prepared by the reaction of hydrated salts of metal (II) acetate with new Schiff base ligand HL, [2‐((4‐(dimethylamino)phenylimino)methyl)‐4,6‐di‐t‐butylphenol] and characterized by different physico‐chemical analyses such as elemental analysis, single XRD, 1H NMR, FTIR and UV–Vis spectroscopic techniques. Their biomolecular docking, antimicrobial and cytotoxicity studies have also been demonstrated. The proposed structure of Schiff base ligand HL and complex 2 are confirmed by Single crystal X‐ray crystallography study. This analysis revealed that metal (II) complexes remain in distorted tetrahedral coordination environments. The electronic properties such as HOMO and LUMO energies are carried out by gaseous phase DFT/B3LYP calculations using Gaussian 09 program. Complex 1 showed a good binding propensity to the DNA and HSA, during the assessment of docking studies. Schiff base ligand HL and its metal (II) complexes, 1–3 screened for their in vitro antimicrobial activities using the disc diffusion method against selected microbes. Complex 1 shows higher antimicrobial activity than complexes 2, 3 and Schiff base ligand HL. According to the results obtained from the cytotoxic studies, Schiff base ligand HL and its metal (II) complexes 1–3 have better cytotoxicity against MCF‐7 cell lines with potency higher than the currently used chemotherapeutic agent cyclophosphamide.