Effect of Cu(II) compound containing dipicolinic acid on DNA damage: a study of antiproliferative activity and DNA interaction properties by spectroscopic, molecular docking and molecular dynamics approaches.

A polymeric compound formulized as [Cu(µ-dipic)2{Na2(µ-H2O)4]n.2nH2O (I), where dipic is 2,6-pyridine dicarboxylic acid (dipicolinic acid, H2dipic), was synthesized by sonochemical irradiation. The initial in-vitro cytotoxic activity of this complex compared with renowned anticancer drugs like cisplatin, versus HCT116 colon cell lines, shows promising results. This study investigated the interaction mode between compound (I) and calf-thymus DNA utilizing a range of analytical techniques including spectrophotometry, fluorimetry, partition coefficient analysis, viscometry, gel electrophoresis and molecular docking technique. The results obtained from experimental methods reveal complex (I) could bind to CT-DNA via hydrogen bonding and van der Waals forces and the theoretical methods support it. Also, complex (I) indicates nuclease activity in the attendance of H2O2 and can act as an artificial nuclease to cleave DNA with high efficiency.Communicated by Ramaswamy H. Sarma.

Structural and functional changes of catalase through interaction with Erlotinib hydrochloride. Use of Chou's 5-steps rule to study mechanisms.

Erlotinib hydrochloride (Erlo) is used in the treatment of non-small cell lung cancer, pancreatic cancer and other types of cancer. Interaction of small molecules with bio-macromolecules can lead to changes in the structure and function of them which is one of the possible side effects of the drugs. In this study, the interaction of Erlo with bovine liver catalase (BLC) using spectroscopic and computational methods is presented in detail. The enzymatic function of BLC decreased to 58.7% when the concentration of the Erlo was 0.5 × 10-7 M. Fluorescence results revealed that the combination of BLC with Erlo undergoes static quenching mechanism (Kb = 1.15 × 104 M-1 at 300 K). The interaction process was spontaneous, exothermic and enthalpy-driven and Van der Waals and hydrogen bonds forces played major roles in the this process. UV-Vis, CD, 3D, and synchronous fluorescence measurements indicated the changes in the microenvironment residues and α-helix contents of BLC in the presence of Erlo. Docking and molecular dynamics presented a stable binding configuration and their results were perfectly consistent with the spectroscopic results. Theoretical calculations and experimental analysis help to fully understand of drug interaction with important biological molecules such as enzymes.

A Pyridyltriazol Functionalized Zirconium Metal-Organic Framework for Selective and Highly Efficient Adsorption of Palladium.

This work reports the synthesis of pyridyltriazol-functionalized UiO-66 (UiO stands for University of Oslo), namely, UiO-66-Pyta, from UiO-66-NH2 through three postsynthetic modification (PSM) steps. The good performance of the material derives from the observation that partial formylation (∼21% of -NHCHO groups) of H2BDC-NH2 by DMF, as persistent impurity, takes place during the synthesis of the UiO-66-NH2. Thus, to enhance material performance, first, the as-synthesized UiO-66-NH2 was deformylated to give pure UiO-66-NH2. Subsequently, the pure UiO-66-NH2 was converted to UiO-66-N3 with a nearly complete conversion (∼95%). Finally, the azide-alkyne[3+2]-cycloaddition reaction of 2-ethynylpyridine with the UiO-66-N3 gave the UiO-66-Pyta. The porous MOF was then applied for the solid-phase extraction of palladium ions from an aqueous medium. Affecting parameters on extraction efficiency of Pd(II) ions were also investigated and optimized. Interestingly, UiO-66-Pyta exhibited selective and superior adsorption capacity for Pd(II) with a maximum sorption capacity of 294.1 mg g-1 at acidic pH (4.5). The limit of detection (LOD) was found to be 1.9 µg L-1. The estimated intra- and interday precisions are 3.6 and 1.7%, respectively. Moreover, the adsorbent was regenerated and reused for five cycles without any significant change in the capacity and repeatability. The adsorption mechanism was described based on various techniques such as FT-IR, PXRD, SEM/EDS, ICP-AES, and XPS analyses as well as density functional theory (DFT) calculations. Notably, as a case study, the obtained UiO-66-Pyta after palladium adsorption, UiO-66-Pyta-Pd, was used as an efficient catalyst for the Suzuki-Miyaura cross-coupling reaction.

Expedient multicomponent synthesis of a small library of some novel highly substituted pyrido[2,3-d]pyrimidine derivatives mediated and promoted by deep eutectic solvent and in vitro and quantum mechanical study of their antibacterial and antifungal activities.

A facile and efficient catalyst- and oxidant-free multicomponent synthesis of a small library of highly substituted pyrido[2,3-d]pyrimidine derivatives is reported. The products were obtained within relatively short reaction times in good to excellent yields in the presence of deep eutectic solvents as media and promoters. Simple purification and reusability of the deep eutectic solvent were the other beneficial factors of the reported protocol. All of the synthesized derivatives were thoroughly screened for possible in vitro antibacterial and antifungal effects against twenty-two bacterial and three fungal pathogens. Some of the prepared pyrido[2,3-d]pyrimidine derivatives showed remarkable antibacterial and antifungal activities in comparison with some typical known antibacterial and antifungal agents. Finally, the derivatives possessing bioactivity effects were subjected to quantum chemical computational studies in order to reveal the probable structural and electronic effects governing the spotted bioactivities. It was found that the observed bioactivities could be best devoted to the HOMO-LUMO energy gap and para delocalization index of the corresponding derivatives.

Magnetic chitosan-(d-glucosimine methyl)benzaldehyde Schiff base for Pb+2 ion removal. Experimental and theoretical methods.

Magnetic chitosan nanocomposite (magnetic chitosan-(d-glucosimine methyl)benzaldehyde, MCS-Sch) on the basis of Schiff base-functionalized magnetite nanoparticles was synthesized. The prepared MCS-Sch was characterized by 1H NMR, FT-IR, XRD, SEM, EDX, DLS, and VSM analysis. The MCS-Sch can be removed from aqueous solution with the help of an external magnet. The efficiency of the synthesized nanocomposite was studied for the Pb(II) ion removal from aqueous solutions. The effects of pH, contact time and initial concentration on the adsorption process were evaluated. Based on the Langmuir isotherm model, the maximum adsorption capacity of MCS-Sch obtained 121.95 mg/g for Pb(II) ion. The binding of prepared nanocomposite and Pb(II) ion was reversible, so the MCS-Sch can maintain its ability for metal ion removal from aqueous solutions. Finally, theoretical calculations showed that the presence of aromatic ring at the prepared magnetic chitosan nanocomposite, MC-Sch, is a favorable factor in Pb(II) ion absorption.