Heteroscorpionate‐based heteroleptic copper(II) complexes: Antioxidant, molecular docking and in vitro cytotoxicity studies

Theoretical, antioxidant, antidiabetic and in silico molecular docking and pharmacokinetics studies of heteroleptic oxovanadium(IV) complexes of thiosemicarbazone-based ligands and diclofenac

A series of new heteroleptic oxovanadium(IV) complexes with the general formula [VOL1-6(Dcf)] (1-6), where L1-6 = thiosemicarbazone (TSC)-based ligands and Dcf = diclofenac have been synthesized and characterized. The spectral studies along with the density functional theory calculations evidenced the distorted square-pyramidal geometry around oxovanadium(IV) ion through imine nitrogen and thione sulfur atoms of TSC moiety, and two asymmetric carboxylate oxygen atoms of diclofenac drug. The complexes were evaluated for in vitro antioxidant activity using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) and superoxide radical scavenging assays with respect to the standard antioxidant drugs butylated hydroxyanisole (BHA) and rutin. The in vitro antidiabetic activity of the complexes was tested with enzymes such as α-amylase, α-glucosidase and glucose-6-phosphatase. The complexes containing methyl substituent showed higher activity than that containing the nitro substituent due to the electron-donating effect of methyl group. The in silico molecular docking studies of the oxovanadium(IV) complexes with α-amylase and α-glucosidase enzymes showed strong interaction via hydrogen bonding and hydrophobic interactions. The dynamic behavior of the proposed complexes was analyzed by molecular dynamics (MDs) simulations, which revealed the stability of docked structures with α-amylase and α-glucosidase enzymes. The in silico physicochemical and pharmacokinetics parameters, such as Lipinski's 'rule of five', Veber's rule and absorption, distribution, metabolism and excretion (ADME) properties predicted non-toxic, non-carcinogenic and safe oral administration of the synthesized complexes.Communicated by Ramaswamy H. Sarma.

8-Alkylmercaptocaffeine derivatives: antioxidant, molecular docking, and in-vitro cytotoxicity studies

Due to their unique pharmacological characteristics, methylxanthines are known as therapeutic agents in a fascinating range of medicinal scopes. In this report, we aimed to examine some biological effects of previously synthesized 8-alkylmercaptocaffeine derivatives. Cytotoxic and antioxidative activity of 8-alkylmercaptocaffeine derivatives were measured in malignant A549, MCF7, and C152 cell lines. Assessment of cGMP levels and caspase-3 activity were carried out using a colorimetric competitive ELISA kit. Computational approaches were employed to discover the inhibitory mechanism of synthesized compounds. Among the twelve synthesized derivatives, three compounds (C1, C5, and C7) bearing propyl, heptyl, and 3-methyl-butyl moieties showed higher and more desirable cytotoxic activity against all the studied cell lines (IC₅₀ < 100 µM). Furthermore, C5 synergistically enhanced cisplatin-induced cytotoxicity in MCF-7 cells (CI < 1). Both C5 and C7 significantly increased caspase-3 activity and intracellular cGMP levels at specific time intervals in all studied cell lines (P < 0.05). However, these derivatives did not elevate LDH leakage (P > 0.05) and exhibited no marked ameliorating effects on oxidative damage (P > 0.05). Computational studies showed that H-bond formation between the nitrogen atom in pyrazolo[4,3-D] pyrimidine moiety with Gln817 and creating a hydrophobic cavity result in the stability of the alkyl group in the PDE5A active site. We found that synthesized 8-alkylmercaptocaffeine derivatives induced cell death in different cancer cells through the cGMP pathway. These findings will help us to get a deeper insight into the role of methylxanthines as useful alternatives to conventional cancer therapeutics.

Metal-free, Mild, and Selective Synthesis of Bis(pyrazolyl)alkanes by Nucleophile-Catalyzed Condensation

Bis(pyrazolyl)alkanes are a prolific class of ligands for catalysis, accessible by the condensation between bis(pyrazolyl)methanones and carbonyls. In this report, we describe a nucleophile-catalyzed innovation on this condensation that avoids the transition metals, high temperatures, reagent excess, and air-sensitive reagents common among the existing protocols. Significantly, this method accommodates sterically hindered and electronically diverse pyrazoles and aldehydes, applicable for systematic ligand optimization. Furthermore, our scope includes azoles and bridging functional groups previously unreported for this reaction, promising for new heteroscorpionate catalysts. We provide the first direct evidence for an elusive reaction intermediate and characterize the most complete mechanism for this condensation.

Cu(ii)-TACN complexes selectively induce antitumor activity in HepG-2 cells via DNA damage and mitochondrial-ROS-mediated apoptosis

A novel 1,4,7-triazacyclononane derivative (btacn), and its related copper complexes, Cu(btacn)Cl₂ and [Cu(btacn)₂]·(ClO₄)₂, exhibit potent anti-proliferation activity towards HepG-2 and HeLa cells, but low cytotoxicity towards normal cell lines.

Binding forces between a novel Schiff base palladium(II) complex and two carrier proteins: human serum albumi and β-lactoglobulin

Ligand binding studies on carrier proteins are crucial in determining the pharmacological properties of drug candidates. Here, a new palladium(II) complex was synthesized and characterized. The in vitro binding studies of this complex with two carrier proteins, human serum albumin (HSA), and β-lactoglobulin (βLG) were investigated by employing biophysical techniques as well as computational modeling. The experimental results showed that the Pd(II) complex interacted with two carrier proteins with moderate binding affinity (K_b ≈ .5 × 10⁴ M^-1 for HSA and .2 × 10³ M^-1 for βLG). Binding of Pd(II) complex to HSA and βLG caused strong fluorescence quenching of both proteins through static quenching mechanism. In two studied systems hydrogen bonds and van der Waals forces were the major stabilizing forces in the drug-protein complex formation. UV-Visible and FT-IR measurements indicated that the binding of above complex to HSA and βLG may induce conformational and micro-environmental changes of two proteins. Protein-ligand docking analysis confirmed that the Pd(II) complex binds to residues located in the subdomain IIA of HSA and site A of βLG. All these experimental and computational results suggest that βLG and HSA might act as carrier protein for Pd(II) complex to deliver it to the target molecules.