Synthesis, characterization, antimicrobial, cytotoxic, DNA-interaction, molecular docking and DFT studies of novel di- and tri-organotin(IV) carboxylates using 3-(3-nitrophenyl)2-methylpropenoic acid

Synthesis, crystallographic, DNA binding, and molecular docking/dynamic studies of a privileged chalcone-sulfonamide hybrid scaffold as a promising anticancer agent

In the present study, a drug-like molecular hybrid structure between chalcone and sulfonamide moieties was synthesized and characterized. The structural peculiarities of the synthesized hybrid were further verified by means of single crystal X-ray crystallography. Furthermore, its biological activity as an anticancer agent was evaluated. The synthesized model of chalcone-sulfonamide hybrid 3 was found to have potent anticancer properties against the studied cancer cell lines. Hence, the in vitro binding interaction of hybrid 3 with Calf thymus DNA (CT-DNA) was studied at a simulated physiological pH to confirm its anticancer activity for the first time. This was investigated by applying different spectroscopic techniques, ionic strength measurements, viscosity measurements, thermodynamics, molecular dynamic simulation and molecular docking studies. The obtained results showed a clear binding interaction between hybrid 3 and CT-DNA with a moderate affinity via a minor groove binding mechanism. The binding constant (Kb) at 298 K calculated from the Benesi-Hildebrand equation was found to be 3.49 × 104 M-1. The entropy and enthalpy changes (ΔS0 and ΔH0) were 204.65 J mol-1 K-1 and 35.08 KJ mol-1, respectively, indicating that hydrophobic interactions constituted the major binding forces. The results obtained from molecular docking and dynamic simulation studies confirmed the minor groove binding interaction and the stability of the formed complex. This study can contribute to further understanding of the molecular mechanism of hybrid 3 as a potential antitumor agent and can also guide future clinical and pharmacological studies for rational drug design with enhanced or more selective activity and greater efficacy.[Figure: see text]Communicated by Ramaswamy H. Sarma.

Antioxidant and anticholinesterase activities of amentoflavone isolated from Ouratea fieldingiana (Gardner) Engl. through in vitro and chemical-quantum studies

Ouratea fieldingiana, popularly known as batiputá, is a tree species easily found in the coastal part of northeastern Brazil. Its leaves are rich in biflavonoids, its major compound being amentoflavone. Biflavonoids are well studied due to their high antioxidant capacity. Alzheimer's disease (AD) is a disease characterized by the progressive loss of neurons. Currently, the pharmacological treatment of AD has four drugs: donepezil, galantamine, rivastigmine and memantine. Where these drugs, with the exception of memantine, are inhibitors of acetylcholinesterase, thus inhibiting the enzyme that destroys acetylcholine, thus increasing the availability of this neurotransmitter. This article aims to determine in vitro and in silico the antioxidant and anticholinesterase action of amentoflavone isolated from the leaves of Ouratea fieldingiana. The antioxidant capacity of amentoflavone was evaluated using the DPPH* free radical scavenging method, with an IC₅₀ of 5.73 ± 0.08 µg/mL. The antiradical properties of the molecule were also studied in silico through several HAT, SET-PT and SPLET mechanisms via DFT M06-2X/6-311++G(d,p). It was found that in the hydrogen atom transfer mechanism (HAT) the best trend was obtained as an anti-radical mechanism. Amentoflavone has the ability to inhibit acetylcholinesterase when tested in vitro, having an IC₅₀ of 8.68 ± 0.73 µg/mL, corroborating its effect in the in silico test, presenting four strong covalent hydrogen bonds for having a bond length up to 2.5 Å. Thus, amentoflavone is an important target for further testing against Alzheimer's disease. Communicated by Ramaswamy H. Sarma.

Synthesis, characterization, in vitro, in silico and in vivo investigations and biological assessment of Knoevenagel condensate β-diketone Schiff base transition metal complexes

A novel Schiff base ligand was synthesized by the Knoevenagel condensation of β-diketone (obtained from substituted Curcumin and Cuminaldehyde) and 4-amino antipyrine. Metal complexes were made from this Schiff base by reacting with metal salts such as Cu(II), Ni(II), Ru(III), VO(IV), and Ce(IV). Physicochemical approaches such as UV-Vis, FT-IR, NMR, EPR, and Mass spectroscopy were used to determine the geometry of the complexes. The thermodynamic stability and biological accessibility of the complexes were investigated using density functional theory (DFT) calculations at the B3LYP/6-31G(d) level. A molecular docking analysis was also performed on 1BNA receptor. Both the Schiff base ligand and metal complexes interacted well to this protein receptor. All metal complexes have a significant potential to bind to CT DNA via the intercalation mechanism. All the in vivo and in vitro screening studies showed that the complexes exhibit higher activities than the free Schiff base.Communicated by Ramaswamy H. Sarma.