Effect of lipophilicity of amylamine and amylglycine ligands on biological activity of new anticancer cisplatin analog

Platinum (II) complex of isopentyl glycine ligand: DNA binding, molecular dynamic, and anticancer activity against breast cancer

In this paper, we performed thorough experimental and theoretical calculations to examine the interaction between Pt derivative, as an anticancer, and ct-DNA. The mode of DNA binding with [Pt(NH3)2(Isopentylgly)]NO3, where Isopentylgly is Isopentyl glycine, was evaluated by various spectroscopic methods, docking, and molecular dynamics simulation studies. UV-Vis and fluorescence spectroscopic titration results and CD spectra of DNA-drug showed this interaction is via groove binding. Also, thermal stability studies or DNA melting temperature changes (ΔTm), as well as the quenching emissions monitoring proved it. Also, the thermodynamic parameter and binding constant displayed that complex-DNA formation is a spontaneous process, and H-binding and also groove binding were found to be the main forces. Theoretical studies stated [Pt(NH3)2(Isopentylgly)]NO3-DNA formation occurs on C-G center on DNA, along with rising DNA-compound stability. IC50 value against the human breast cell line probably is due to the Isopentyl glycine ligand in the structure of the Pt compound, and it was obtained more than cisplatin and less than carboplatin against the MCF7 cell.Communicated by Ramaswamy H. Sarma.

Green Synthesis and Bioactivity of Aliphatic N-Substituted Glycine Derivatives

Standard amino acids have an asymmetric α-carbon atom to which -COOH, -NH2, -H, and -R groups are bonded. Among them, glycine is the simplest (R = -H) with no asymmetric carbon, and other natural amino acids are C-substituted of glycine. Here, we have designed and made a green synthesis of some new N-substituted glycine derivatives with R-(NH)CH2-COOH formula, where R is flexible and hydrophobic with different chain lengths and benches of the type propyl, butyl, sec-butyl, tert-butyl, pentyl, isopentyl, tert-pentyl, hexyl, 2-aminoheptyl, and octyl. These glycine derivatives were characterized by recording their melting points and FT-IR, mass, 1H NMR, and 13C NMR spectra. DFT studies revealed that 2-aminoheptyl glycine had the highest electronegativity value and can thus act as a good bidentate ligand for the metal centers. ADME comparative results and bioavailability radars indicated that both octyl- and 2-aminoheptyl glycine had the most lipophilicity, making them good agents in cell passing. Furthermore, lipophilicity determination showed that octyl glycine was the best and propylgly was more soluble than others. Based on solubility, lipophilicity, and dipole moment values, propyl- and 2-aminoheptyl-glycine were considered for bio-macromolecular interaction studies. Thus, the interaction of these two agents with DNA and HSA was studied using absorption spectroscopy and circular dichroism techniques. Due to the presence of the R-amine group, they can interact with the DNA by H-binding and hydrophobicity, while electrostatic mode could not be ruled out. Meanwhile, molecular docking studies revealed that octyl- and 2-aminoheptyl glycine had the highest negative docking energy, which reflects their higher tendency to interact with DNA. The DNA binding affinity of two candidate AAs was determined by viscosity measurement and fluorescence emission recording, which confirms that groove binding occurs. Also, the toxicity of these synthesized amino acid derivates was tested against the human foreskin fibroblast (HFF) cell line. They showed IC50 values within the range of 127-344 μM after 48 h with the highest toxicity for 2-aminoheptyl glycine.

Spectroscopy and molecular dynamic study of the interaction of calf thymus DNA by anticancer Pt complex with butyl glycine ligand

Despite the past few decades since the discovery of anticancer drugs, there is still no definitive treatment for its treatment. Cisplatin is a chemotherapy medication used to treat some cancers. In this research, the DNA binding affinity of Pt complex with butyl glycine ligand was studied by various spectroscopy methods and simulation studies. Fluorescence and UV-Vis spectroscopic data showed groove binding in ct-DNA-[Pt(NH₃)₂(butylgly)]NO₃ complex formation by the spontaneous process. The results were also confirmed by small changes in CD spectra and thermal study (T_m), as well as the quenching emission of [Pt(NH₃)₂(butylgly)]NO₃ complex on DNA. Finally, thermodynamic and binding parameters displayed that hydrophobic forces are the main forces. Based on docking simulation, [Pt(NH₃)₂(butylgly)]NO₃ could bind to DNA and via minor groove binding on C-G center on DNA, formed a stable DNA complex.

Biological Activity of Two Anticancer Pt Complexes with a Cyclohexylglycine Ligand against a Colon Cancer Cell Line: Theoretical and Experimental Study

Because of their extraordinary ability to disrupt the natural structure of nucleic acids, metal complexes could be used in cancer therapy. In this study, cyclohexylglycine (HL) as a ligand and two new Pt complexes, [Pt(NH₃)₂(L)]NO₃ (1) and [Pt(bipy)(L)]NO₃ (2), were synthesized and characterized by elemental analysis, LC-MS, UV-vis spectrometry, FT-IR, ¹H NMR spectroscopy, ¹³C NMR spectroscopy, ¹⁹⁵Pt NMR spectroscopy, HPLC analysis, and single-crystal X-ray diffraction. Complex 2 crystallized in the orthorhombic Pbca space group, and density functional theory (DFT) was used to describe its structural parameters were described in detail. These complexes can be classified as oral medications and drug-like molecules based on a comparison of their absorption, distribution, metabolism, and excretion assessment. Quantum chemical descriptors (QCDs) were determined using DFT calculations to predict the tendency of DNA to approach these complexes. During the determination of the function of the metallodrug in DNA binding, the fluorescence data indicated that static quenching took place for all ligands and complexes with higher DNA binding affinity. CD and isothermal absorption studies indicate the presence of electrostatic and groove binding for the amine derivative and that DNA binds with the bipy moiety via groove binding. Furthermore, the interaction modes were determined using molecular docking to investigate the binding of these compounds with the target DNA molecule. According to docking investigations, binding energies of -5.7, -11.56, and -10.00 kcal/mol for HL and complexes 1 and 2, respectively, indicate partially electrostatic and groove binding. The anticancer activities of the Pt(II) complexes were tested against the HCT116 human colon cancer cell line, with IC₅₀ values of 35.51 and 51.33 μM for 1 and 2, respectively, after 72 h. These values show that the inhibitory effect of complex 1 was better than those of 2 and carboplatin (IC₅₀ = 51.94 μM).

Property evaluation of two anticancer candidate platinum complexes with N-isobutyl glycine ligand against human colon cancer

Small molecules have potential usage in cancer therapy due to their remarkable potency of disarranging the natural structure of nucleic acids. In this study, two complexes [Pt(NH₃)₂(IBgly)]NO₃ (1) and [Pt(bipy)(IBgly)]NO₃ (2) based on Pt(II), N-isobutylglycine (IBgly), 2,2'-bipyridine, and ammonia were prepared and characterized by spectroscopic methods. Pharmacokinetic ADME data, absorption, distribution, metabolism, excretion, and bioavailability radar showed two complexes can be introduced for Pt-based anti-cancer drugs. Mechanism of tumor inhibition and DNA interaction of these compounds was studied by UV-Vis, fluorescence, and CD spectroscopies. Also, thermodynamic parameters and the binding constants were calculated through absorption measurements. The fluorescence data showed that a static quenching mechanism occurred for both complexes with a binding constant and binding affinity towards DNA (K_b ≈ 3500 M^-1 and k_q ≈ 2.1 × 10¹¹ M^-1 s^-1). The thermodynamic parameters indicated electrostatic approaching and groove binding were more feasible than intercalation mode between Pt(II) complexes and DNA. CD spectra indicated the increasing intensity of the positive band and the negative band decreasing. Density functional theory calculations confirmed the experimental data and determined the quantum chemical descriptors including total energy, hardness, chemical potential, electrophilicity, electronegativity, etc. According to this, the binding tendency of these compounds with DNA could be predicted. Further, molecular docking studies were also performed. Docking studies revealed that the desolvation, hydrogen, and electrostatic binding were effective for the interaction between complexes and DNA with binding energy (- 10.44 and - 9.57 kcal/mol) for complexes 1 and 2, respectively, which is mainly of partially electrostatic and groove binding type. The cytotoxic activity of Pt complexes was examined against human colon cancer cell line which indicated good activity with IC₅₀ values of (41.66 and 47.30 μM) for both complexes after 72 h, respectively. Also, they demonstrated more inhibitory effects compared to carboplatin.

Synthesis, characterization, cytotoxicity and DNA/BSA binding of two amino acid palladium(II) complexes derived from alanine and valine

Two novel palladium(II)-amino acid complexes, [Pd(Ala)2]·H2O (PA) and [Pd(Val)2].H2O (PV) (Ala = alanine; Val = valine) were synthesized and characterized through FTIR, UV/Vis, 1H-NMR spectroscopies, CHN analysis, X-ray crystallography and molar conductivity measurement. Furthermore, cytotoxicity of Pd(II) complexes against human leukemia cancer cell line, MOLT4 showed promising cancer cell death (CC50 = 0.71 ± 0.046 µM for PA; CC50 = 0.85 ± 0.063 µM for PV) that were less than cisplatin (1.59 ± 0.25 µM). Moreover, the interaction of both the complexes with DNA and BSA was studied using UV-Vis absorption and emission spectroscopic techniques that demonstrated the bindings occurred via van der Waals forces and hydrogen bond. Furthermore, the fluorescence titration showed that static quenching mechanism plays predominate role in binding process. All results showed that both complexes have more binding tendency to DNA in compared to BSA that can be a significant achievement for further medical purposes as a potential antitumor candidate. Finally, molecular docking simulation was performed for PA and PV complexes with DNA and BSA and demonstrated both complexes bind to the groove of DNA mainly by hydrogen bond and interact with site I of BSA via hydrogen bond as well.

Spectroscopic and electrochemical approaches for the analysis of interaction between textile dye 231 and salmon sperm DNA

DNA is one of the most critical targets for many artificial agents listed as carcinogens. Most of them irreversibly bind to the DNA and induce genome mutation; therefore, it is vital to study the nature of binding of these molecules to anticipate their toxicity. The interaction between the textile dye reactive red 231 and salmon sperm double-stranded DNA (ss-dsDNA) was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and ultraviolet-visible spectroscopy (UV–vis spectroscopy). Changes in the anodic current signals of the dye were observed in the presence and absence of ss-dsDNA at a glassy carbon electrode (GCE) using CV. The diffusion coefficient (D) was found to be 2.2 × 10–7 and 9.5 × 10–8 cm2 s−1 from the CV data for the free dye and dye-DNA complex, respectively. Electrochemical and UV–vis spectroscopy indicated 1:1 complex formation of the dye with DNA. The binding constant (kb) between the dye and DNA was calculated to be 5.4 × 105 M–1 and 4.9 × 105 M–1 at pH 4.0 using CV and UV–vis spectroscopy, respectively. Overall, these results suggest that the dye binds to DNA through the combined effect of intercalation and electrostatic interactions. DNA damage was also detected through changes in the voltammetric behaviour of the dye.

Investigating the anticancer properties of the two new platinum complexes with iso- and tert-pentylglycine by the DFT, molecular docking, and ADMET assessment and experimental confirmations

In this study, two new anticancer platinum complexes formulated as [Pt(bpy)(L)]NO3 were synthesized using the iso and tert-pentylglycine ligands, two structural isomer ligands, to investigate side branches effect on the complex-DNA interaction. According to the comparative results of the ADMET assessment, these compounds can be considered as the drug-like molecules and oral medication. Mechanism of tumor inhibition and DNA binding parameters indicated the higher ability of the tert-isomer and also, both complexes acted through the disruption of the base pairs and stacks of helicity by the endothermic process. Fluorescence spectroscopy showed that the quenching mechanism is static for both drugs with large binding constant and high binding affinity towards the DNA. Also, the amount of binding constant of the tert -isomer was about 14 times of another structural isomerous complex. CD spectra indicated the conversion of the B-DNA into A-DNA form via electrostatic interaction for positively charged complexes. The cytotoxic data showed that both compounds have antiproliferative effects against the MCF-7 cell line and the inhibitory effect of the iso-derivative was better than the tert-one. Docking studies showed that the desolvation energy and hydrogen bond are more effective between the other interactions. The torsional free energy for both complexes mainly provided the groove binding along with partially electrostatic and intercalate binding. According to the density-functional theory data and because of positive electron density on the surface of complexes and facilitating of the metal drug to DNA phosphate groups approaching, both complexes may be good candidates for the anticancer drugs. Two new anticancer Pt(II) complexes were synthesized with glycine derivatives. In vitro cytotoxicity effects were tested against the human breast cancer cell line of MCF-7. Moreover, the modes of DNA binding with synthesized compounds were investigated using ADME prediction, DFT, molecular docking and spectroscopic methods.

Some new anticancer platinum complexes of dithiocarbamate derivatives against human colorectal and pancreatic cell lines

Cisplatin, carboplatin and oxaliplatin and their analogs are effective anticancer agents, but their clinical using is limited by some serious side effects. S,S donor ligands such as dithiocarbamates can be used to reduce some side effects. In this study, some novel water soluble complexes with formula of [Pt(bpy)(R.dtc)]NO₃, where bpy is bipyridine and R.dtc is amyl-, isopentyl- or tertamyl-dtc (n-pentyl-, 3-metyl-butyl- and 2-methylbutan-dithiocarbamate, respectively) have been synthesized and characterized by elemental analysis, conductivity measurements and chemical analysis. The cytotoxic activities of synthesized complexes were investigated against human adenocarcinoma colorectal cell line (HT29) and human pancreatic cell line (Panc1), and compared with cisplatin and oxaliplatin, which display more anticancer activity for [Pt(bpy)(isopentyl.dtc)]NO₃. The experimental fluorescence and circular dichroism results illustrated partially groove binding of [Pt(bpy)(amyl.dtc)]NO₃ and [Pt(bpy)isopentyl.dtc)]NO₃ on DNA, while [Pt(bpy)(tertamyl.dtc)]NO₃ complex, can bind to DNA via intercalation. Finally, molecular docking simulation data of DNA interaction with three synthesized complexes showed [Pt(bpy)(amyl.dtc)]NO₃ complex has the highest tendency and negative docking energy in structural change of DNA.Communicated by Ramaswamy H. Sarma.

Photocytotoxic Pt(iv) complexes as prospective anticancer agents

The use of Pt(iv) complexes as potential anticancer drugs is attractive, because they have higher stability and less side effects than Pt(ii) compounds. Moreover, some Pt(iv) complexes can also be activated with light, opening an avenue to photochemotherapy. Our purpose is to widen the library of photoactivatable Pt(iv)-based prodrugs and here we report on the oxidation of the Pt(ii) compound [PtCl(4'-phenyl-2,2':6',2''-terpyridine)][CF₃SO₃] (1) with PhICl₂ or H₂O₂. The synthetic procedure avoids the formation of multiple species: the treatment with PhICl₂ produces the Pt(iv) complex with axial chlorides, [PtCl₃(4'-phenyl-2,2':6',2''-terpyridine)][CF₃SO₃] (2), while H₂O₂ oxidation and post-synthesis carboxylation produce [Pt(OCOCH₃)₂Cl(4'-phenyl-2,2':6',2''-terpyridine)][CF₃SO₃] (3), bearing acetates in the axial positions. 2 and 3 are stable in physiological-like buffers and in DMSO in the dark, but undergo photoreduction to 1 upon irradiation at 365 nm. Their stability toward reduction is a fundamental parameter to consider: cyclic voltammetry experiments show that the 2 electron reduction Pt(iv) → Pt(ii) occurs at a more negative potential for 3, because of the greater stabilization provided by the acetate axial groups; noteworthily, 3 is stable for hours also in the presence of mM concentration of glutathione. The cytotoxicity of 2 and 3 toward A2780 and A2780cis cell lines reveals that 3 is the least toxic in the dark, but is able to produce cytotoxic effects far higher than cisplatin when irradiated. To shed light on the mechanistic aspects, the interaction with protein and DNA models has been explored through high-resolution mass spectrometry revealing that 2 and 3 behave as prodrugs, but are able to bind to biological targets only after irradiation.

Nonionic but water soluble, [Glycine-Pd-Alanine] and [Glycine-Pd-Valine] complexes. Their synthesis, characterization, antitumor activities and rich DNA/HSA interaction studies

Two novel, neutral and water soluble Pd(II) complexes of formula [Pd(Gly)(Ala)] (1) and [Pd(Gly)(Val)] (2) (Gly, Ala, and Val are anionic forms of glycine, alanine, and valine amino acids, respectively) have been synthesized and characterized by FT-IR, UV-Vis, ¹H-NMR, elemental analysis, and molar conductivity measurement. The data revealed that each amino acid binds to Pd(II) through the nitrogen of -NH₂ and the oxygen of -COO^- groups and acts as a bidentate chelate. These complexes have been assayed against leukemia cells (K₅₆₂) using MTT method. The results indicated that both of the complexes display more cytotoxicity than the well-known anticancer drug, cisplatin. The interaction of the compounds with calf thymus DNA (CT-DNA) and human serum albumin (HSA) were assayed by a series of experimental techniques including electronic absorption, fluorescence, viscometry, gel electrophoresis, and FT-IR. The results indicated that the two complexes have interesting binding propensities toward CT-DNA as well as HSA and the binding affinity of (1) is more than (2). The fluorescence data indicated that both complexes strongly quench the fluorescence of ethidium bromide-DNA system as well as the intrinsic fluorescence of HSA via static quenching procedures. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) calculated from the fluorescence studies showed that hydrogen bonds and van der Waals interactions play a major role in the binding of the complexes to DNA and HSA. We suggest that both of the Pd(II) complexes exhibit the groove binding mode with CT-DNA and interact with the main binding pocket of HSA. Communicated by Ramaswamy H. Sarma.

Therapeutic applications of selenium-derived compounds

Selenium is a biocompatible element and participates in several biochemical reactions occurring in the human body. Its biocompatibility and minimal toxicity has attracted researchers to develop selenium-based drugs. Hence, recent developments on biomedical applications of selenium-based compounds have been discussed. A structure activity relationship has also been interpreted.