New organotin(IV) derivatives of dipeptides as models for metal-protein interactions:in vitro anti-tumour activity

Syntheses, structures, in vitro cytostatic activity and antifungal activity evaluation of four diorganotin(iv) complexes based on norfloxacin and levofloxacin

Four organotin(iv) complexes have been designed and synthesized from the reactions of R2SnO (R = Me, Ph) with the corresponding ligands norfloxacin and levofloxacin. And the cytostatic and antifungal activity test have been done.

Unfolding biological properties of a versatile dicopper(II) precursor and its two mononuclear copper(II) derivatives

Synthesis, inter-conversions and biological study of the dichloro bridged dicopper(II) compound [CuLCl]₂ (1) and its two mononuclear derivatives [CuLCl(H₂O)]·H₂O (2) and [CuLCl(py)] (3) (HL=2-(2-pyridylmethyleneamino)benzenesulfonic acid) are described. The dimeric compound 1 collapses into monomers 2 and 3 in the presence of coordinating solvents, water and pyridine, respectively, and 1 is regenerated upon simple stirring of 2 or 3 in methanol. The reactions of 1 with neutral (present study) and charged (earlier studies) ligands result in monomeric and multimeric compounds, respectively, attesting that it is a versatile dicopper(II) precursor. The anticancer activity of these copper complexes (1-3) was screened against lung (A-549) and breast (MDA-MB-231) human cancer cell lines. The IC₅₀ (half maximal inhibitory concentration) value for one (3) of the compounds suggests preferential cytotoxicity against breast cancer MDA-MB-231 cell line. Furthermore, the IC₅₀ value obtained for complex 3 is found to be almost two-fold times cytotoxic than the standard drug cisplatin. In addition, the underlying possible mechanism of its apoptosis-inducing efficacy in MDA-MB-231 cells has been rationalized by using flow cytometry (FACS) and Hoechst 33342/propidium iodide (PI) fluorescence staining. The stimulation of apoptotic induction for complex 3 has further been affirmed by reactive oxygen species (ROS) generation and mitochondrial aggregations studies.

Sulfonated Schiff base Sn(IV) complexes as potential anticancer agents

Syntheses, crystal structures and biological activities of the diphenoxo-bridged diorgano dinuclear Sn(IV) compounds [Sn(Et)₂(HL)(H₂O)]₂ (1) and [Sn(n-Bu)₂(HL)(H₂O)]₂ (2) derived from the Schiff base 2-[(2,3-dihydroxyphenyl)methylideneamino]benzenesulfonic acid trihydrate (H₃L·3H₂O) are described. The monoprotonated form (HL^2-) of the Schiff base behaves as O,O'-bidentate ligand, chelating the metal by the two phenoxo oxygen atoms. The hexacoordinated metal centres in 1 and 2 are bridged by a phenoxo oxygen and the remaining coordination positions are fulfilled by the other phenoxo oxygen, two organic groups (ethyl for 1 and n-butyl for 2) and a water molecule. A two dimensional zigzag sheet in 1 and three dimensional polymeric networks in H₃L·3H₂O and 2 are stabilized by a number of non-covalent, H-bonding and π⋯π stacking interactions. The DNA binding activities of these complexes have been studied by UV-vis and fluorescence spectroscopies. Their antiproliferative efficacies have been evaluated on A-549, HeLa and MDA-MB-231 cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. IC₅₀ values (1.35±0.23, 2.43±0.54 and 1.74±0.04μM for 2) are indicative of a substantial cytotoxicity of 2, mainly towards the A-549 lung cancer cell line. The greater antiproliferative efficacy of 2has further been studied by fluorescence activated cell sorting (FACS) and nuclear morphology by Hoechst/propidium iodide (PI) double staining method. The possible mode of the apoptotic pathway for 2has been substantiated by the reactive oxygen species (ROS) generation studies.

Mode of action of tin-based anti-proliferative agents: Biological studies of organotin(IV) derivatives of fatty acids

Some organotin(IV) carboxylates of the general formula RnSn(L)m [n=3, m=1, R=Me, Pr, Bu and Ph; n=2, m=2, R=Me, Bu and Oct; L=anion of lauric (HLA), stearic (HSA) and myristic acid (HMA)] have been synthesized and characterized by various spectroscopic studies. Tri- and diorganotin(IV) carboxylates adopt trigonal-bipyramidal and octahedral geometry around tin atom, respectively. They have been screened in vitro for anti-tumor activity against cancer cell lines of human origin, viz. MCF-7 (mammary), HEK-293 (kidney), PC-3 (prostate), HCT-15 (colon) and HepG-2 (liver). Enzyme assays viz. lipid peroxidase, glutathione peroxidase, glutathione reductase and total glutathione assay have been carried out to explore the cause of their cytotoxiciy. The results indicate that ROS (reactive oxygen species) generation may be responsible for their cytotoxicity but elevation in LDH (lactate dehydrogenase) suggests that necrosis cannot be excluded. Further, DNA (deoxyribonucleic acid) fragmentation, acridine orange and comet assay support the fact that the apoptosis is the main cause of cytotoxicity of organotin(IV) carboxylates, whereas the necrosis plays a minor role. The anti-inflammatory activity evaluation shows that the complexes possess moderate activity. Results of acute toxicity of the complexes have also been discussed.

Synthesis and characterization of Co(ii) and Fe(ii) peptide conjugates as hydrolytic cleaving agents and their preferential enantiomeric disposition for CT-DNA: structural investigation of l-enantiomers by DFT and molecular docking studies

Molecular docked model of Co(ii) peptide conjugate with DNA and the mechanism of hydrolytic cleavage of pBR322 DNA.

Synthesis, Characterization, and Thermal and Antimicrobial Activities of Some Novel Organotin(IV): Purine Base Complexes

A new series of organotin(IV) complexes with purine bases theophylline (HL1) and theobromine (L2) of the types R3Sn(L1), R2Sn(L1)Cl, R3Sn(L2)Cl, and R2Sn(L2)Cl2(R = C6H5CH2–;p-ClC6H4CH2–) have been synthesized in anhydrous THF. The complexes were characterized by elemental analysis, conductance measurements, molecular weight determinations, UV-vis, IR,1H,13C NMR, and mass spectral studies. Various kinetic and thermodynamic parameters of these complexes have also been determined using TG/DTA technique. The thermal decomposition techniques indicate the formation of SnO2as a residue. The results show that the ligands act as bidentate, forming a five-member chelate ring. All the complexes are 1 : 1 metal-ligand complexes. In order to assess their antimicrobial activity, the ligands and their corresponding complexes have also been testedin vitroagainst bacteria (E. coli, S. aureus, andP. pyocyanea) and fungi (Rhizopus oryzaeandAspergillus flavus). All the complexes exhibit remarkable activity, and the results provide evidence that the studied complexes might indeed be a potential source of antimicrobial agents.

Trimethylammonium dichloridotriphenylstannate(IV)

In the structure of the title monomeric coordination salt, (C₃H₁₀N)[Sn(C₆H₅)₃Cl₂], the Sn^IV atom is five coordinate, with the SnC₃Cl₂ entity in a trans trigonal–bipyramidal arrangement and the chlorine atoms in apical positions. In the crystal, the cations and anions are connected by N—H⋯Cl hydrogen bonds.

Interaction of 5'-Guanosine Monophosphate with Organotin(IV) Moieties: Synthesis, Structural Characterization, and Anti-Inflammatory Activity

Reaction(s) of 5'-guanosine monophosphate (5'GMP) with di- and triorganotin(IV) chloride(s) led to formation of organotin(IV) derivatives of general formulae, [R2Sn(5'-GMP)·H2O] n and [(R'3Sn)2(5'-GMP)·H2O] n , where R = Me, n-Bu, and Ph; R' = Me, i-Pr, n-Bu, and Ph; (5'-GMP)(2-) = 5'-guanosine monophosphate. An attempt has been made to prove the structures of the resulting derivatives on the basis of FT-IR, multinuclear (1)H, (13)C, and (119)Sn NMR and (119)Sn Mössbauer spectroscopic studies. These investigations suggest that both di- and triorganotin(IV)-5'-guanosine monophosphates are polymeric in which (5'-GMP)(2-) is bonded through phosphate group resulting in a distorted trigonal bipyramidal geometry around tin. The ribose conformation in all of the derivatives is C3'-endo, except diphenyltin(IV) and tri-i-propyltin(IV) derivatives where it is C2'-endo. All of the studied derivatives exhibited mild-to-moderate anti-inflammatory activity (~15.64-20.63% inhibition) at 40 mg kg(-1) dose and LD50 values > 400 mg kg(-1) in albino rats.