Selçuk Gümüş

Considering the extremely valuable biological and pharmaceutical properties of quinolines, novel water-soluble quinoline-based conjugates were designed and synthesized. In vitro antioxidant activities, such as free radical scavenging, metal chelating, and reducing-power activities, of the newly synthesized compounds (WQ-1, WQ-2, WQ-3, WQ-4, and WQ-5) were determined. Although the highest scavenging activity (41.21 ± 1.18%) and chelating activity (23.53 ± 0.97%) at a concentration of 500.0 µg/ml were observed in WQ-4, it was determined that WQ-5 had the highest reducing-power ability (0.417 ± 0.0116). The synthesized compounds were also tested for their antimicrobial activities against two Gram-positive and two Gram-negative bacteria, and it was determined that only WQ-3 showed low activity against Enterococcus hirae and Staphylococcus aureus. DNA-binding activities of the compounds were also studied using calf thymus DNA (CT-DNA). Additionally, the three-dimensional geometries and some electronic properties of the synthesized compounds were investigated with the density functional theory approach at B3LYP/6-31++G(d,p) level of theory.

Cancer, defined by the continuous, uncontrollable proliferation of cells in the human body, is a disease with a rapidly increasing incidence and mortality rate. Scientists are looking for novel ways to cure and prevent this sneaky disease because of the toxicity of contemporary chemotherapy and the cancer cells’ resilience to anticancer drugs. Determining the effect of herbal medicines, which do not have as harmful side effects as synthetic drugs, on cancer cell lines is an essential preliminary study in the production of effective drugs against cancer. In this study, the phenolic acid profile, antioxidant capacity, and cytotoxicity of the medicinal plant Mespilus germanica (MG) leaf extract were determined, and its effects on the expression of some apoptotic, necrotic, and autophagic pathway genes of MCF7 (Human breast cancer line) and A549 (Human lung cancer line) and healthy HDF (Human Dermal Fibroblasts) cells were investigated for the first time. The LCMS device detected many important phenolic compounds previously reported to act against cancer cells in Mespilus germanica leaf extract. DPPH and total phenolic content showed high antioxidant capacity. The cytotoxicity of MG was determined by the MTT method. The levels of mRNA transcription for Atg5, Atg3, Rıpk1, Bcl2, Bax, Apaf1, Caspase-8, Caspase-7, Caspase-3, and Caspase-9, as well as the expression patterns of the DNA damage markers P53 and Parp-1 genes, were assessed. MG leaf extract did not cause significant toxicity against healthy HDF cells. However, it had a cytotoxic effect on A549 and MCF7 cancer cell lines, increasing the transcription levels of essential genes involved in cell death mechanisms. This research is the first to analyze the phenolic components and antioxidant capabilities of leaf extracts from Mespilus germanica. Additionally, it investigates the impact of these extracts on crucial genes involved in cell death pathways of A549 lung cancer, MCF7 breast cancer, and non-cancerous HDF (Human Dermal Fibroblasts) cells. Graphical Abstract

In this research, a green alga (Paulschulziapseudovolvox sp.) based biological photovoltaic cell (BPV) was designed. This clean energy‐friendly BPV produced photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on gold electrodes. In the cell, the photoanode was first coated with a gold‐modified poly 4‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)benzamine polymer, (P(SNS‐NH2)). Cytochrome C (Cyt. C) material was used to provide crosslink formation with bis‐aniline covalent bonds with the conductive polymer using electrochemical techniques. Paulschulziapseudovolvox sp., one of the green algae that can convert light energy into chemical energy, is attached to this layered electrode surface. The cathode of the cell is attached to the gold electrode surface with poly 4‐(4HDithieno[3,2‐b : 2′,3′‐d]pyrrole‐4‐yl)aniline (P(DTP‐Aryl‐Amine)). Then, the bilirubin oxidase enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light thanks to green algae, oxidizes and splits water, and oxygen is obtained at the photoanode electrode. At the cathode electrode, the oxygen gas is reduced to water by the bio‐electro‐catalytic method. To obtain high photocurrent from the BPV, necessary electrochemical and chemical optimizations were made during the design of the system to increase the amount of electrons that were transferred and fasten its transfer rate. While the photocurrent value generated by the designed BPV in optimum conditions and in the pseudo‐steady state is 10 mA/m2, the maximum power value obtained is 46.5 mW/m2. In addition to the production of the green algae‐based BPV generating highly efficient electricity which is the main of target of this study, some studies have also been carried out to show whether this system can be used as a pesticide biosensor. Atrazine and diuron biosensing via the BPV system was analytically characterized and recovery and interference studies related to pesticide biosensor property of the BPV were also investigated.

Synthesis of novel fluorescent quinoline‐pyrene conjugates is described. The key intermediates 2‐substituted 8‐propynyloxy quinoline and azidomethyl pyrene were connected with triazole bridge by 1,3‐dipolar alkyne‐azide cycloaddition reaction. Density functional theory methodology with B3LYP/6‐311++G(d,p) basis set was applied computationally to gather information about the structural and electronic properties of the quinoline‐pyrene compounds. In addition, the metal coordination properties of the triazole bridged molecules were investigated through interactions with several cations. The effect of metal coordination on the stability of the complexes have also been discussed through computations on chelatoaromaticity.

We report, for the first time, a detailed crystallographic study of the supramolecular arrangement for a set of zinc(II) Schiff base complexes containing the ligand 2,6‐bis((E)‐((2‐(dimethylamino)ethyl)imino)methyl)‐4‐R‐phenol], where R=methyl/tert‐butyl/chloro. The supramolecular study acts as a pre‐screening tool for selecting the compartmental ligand R of the Schiff base for effective binding with a targeted protein, bovine serum albumin (BSA). The most stable hexagonal arrangement of the complex [Zn−Me] (R=Me) stabilises the ligand with the highest FMO energy gap (ΔE=4.22 eV) and lowest number of conformations during binding with BSA. In contrast, formation of unstable 3D columnar vertebra for [Zn−Cl] (R=Cl) tend to activate the system with lowest FMO gap (3.75 eV) with highest spontaneity factor in molecular docking. Molecular docking analyses reported in terms of 2D LigPlot+ identified site A, a cleft of domains IB, IIIA and IIIB, as the most probable protein binding site of BSA. Arg144, Glu424, Ser428, Ile455 and Lys114 form the most probable interactions irrespective of the type of compartmental ligands R of the Schiff base whereas Arg185, Glu519, His145, Ile522 act as the differentiating residues with ΔG=−7.3 kcal mol⁻¹.

Schiff base derivatives with anthracene- and pyrene-based units, A1-A6 and P1-P6 were synthesized (89%–99% yields). Schiff base derivatives were designed to possess an heterocyclic moiety on one side to enhance the coordination ability towards metals. To investigate the biological assay of the newly synthesized compounds, their DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, metal chelating, reducing power, antibacterial and DNA binding activities were tested. A6 (63.1%) showed the maximum free radical scavenging activity among all. However, compound P3 at concentration of 200 μg/mL possessed the highest metal chelating (45.8%) activity and power of reduction. In addition, P3 and A6 showed antibacterial activity against all bacteria tested and both compounds were very well bound to CT-DNA. Density functional theory method with B3LYP/6-311++G(d,p) basis set was performed to get information about the structural and electronic properties of the present compounds. In addition, the metal coordination properties of the dimers of the parent Schiff bases were investigated through interactions with Zn2+.

In this chapter mono, di, tri and tetraaza substituted phenanthrene derivatives have been investigated computationally with B3LYP/6-31 + G(d,p) level of theory. Substitution of carbon atom of the main structure with nitrogen obviously disturbs the aromaticity, indeed it decreases it. Thus, the idea of regaining of the aromaticity back by using electron withdrawing groups came across. As a result of the computational calculations, energetically most unfavored structures have been found to be those where aza substitutiona are vicinal. Secondly, the aromaticities of the present species depend on the position of the centric substituent. In addition, the effect position of the side substituent has been considered. The system becomes more aromatic (possess greater negative NICS values or smaller HOMA value) when the electron withdrawing atoms or groups are adjacent to the centrically substituted heteroatoms.