Browsing by Author "Muglu, H."

Now showing 1 - 6 of 6

Kinetic Insights into the Antioxidant Effect of Isatin-Thiosemicarbazone in Biodiesel Blends
(2024.01.01) Karakullukçu, N.T.; Muglu, H.; Yakan, H.; Yilmaz, V.M.; Marah, S.; Ince, I.A.
Biodiesel has several drawbacks, such as being prone to oxidation, having reduced stability, and having limited storage time. Antioxidants compatible with biodiesel are being used to address its drawbacks. Utilizing antioxidants effectively improves the quality of biodiesel. Enhancing the quality of biodiesel for use as a clean energy source benefits both the global economy and ecology. Therefore, we believe that our work will contribute to the advancement of the biodiesel industry worldwide. This study used blends consisting of 20% biodiesel and 80% diesel fuel. Isatin-thiosemicarbazones were tested as additives in blends at a concentration of 3000 parts per million (ppm) using an oxifast device and were compared with the chemical antioxidant Trolox. FT-IR, DSC, and TGA were used to characterize these samples. DSC measured sample crystallization temperatures (Tc). Samples with antioxidants showed decreased values compared to the non-antioxidant diesel sample D100. Several DSC tests were conducted to determine the antioxidant strengths of various samples. The results show that the FT-IR spectrum's antioxidant effect regions grow clearer with antioxidants. The extra antioxidant is effective. Biodiesel's oxidative stability improves with isatin-thiosemicarbazones at varying concentrations. The kinetics of thermal decomposition of isatin-thiosemicarbazones under non-isothermal conditions were determined using the Kissinger, Ozawa, and Boswell techniques. The activation energies of compounds 1 and 2 were calculated as 137-147 kJ mol-1 and 173-183 kJ mol-1, respectively.
Novel 1,3,4-thiadiazol derivatives including α-lipoic acid: Synthesis, characterization, and antioxidant properties
(2024.01.01) Bakir, T.K.; Ashweeqi, M.A.A.; Muglu, H.
In this study, new 1,3,4-thiadiazole-2-amine derivatives containing different substitution groups were synthesized in order to increase the free radical quenching ability of alpha-lipoic acid. The target thiadiazole amines were derived from thiosemicarbazide reagent. Structural analysis for the synthesized compounds (1-8) was carried out using modern spectroscopic techniques including FTIR, NMR, EIMS spectral analyses. The antioxidant properties of each molecule were elucidated by calculating% inhibition as well as significant IC50 values using the 1,1diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging method. The antioxidant activities of the compounds were compared against ascorbic acid, a water-soluble antioxidant, and against alpha-lipoic acid, the starting molecule of the synthesis step, which actually showed a low DPPH quenching activity. While lipoic acid had a reference standard value of 15,625.02 +/- 0.96 mu M, compound 8 was the compound with the highest antioxidant activity with an IC50 value of 433.69 +/- 0.04 mu M. The obtained data suggested that the (N-H) proton in the thiadiazole structure bound to lipoic acid plays an important role in binding to the DPPH radical. This study may provide a source for the synthesis of alpha-lipoic acid-based thiadiazole derivatives, new compounds with antioxidant properties that can be used in medicine and pharmacy.
Novel asymmetric biscarbothioamides as Alzheimer's disease associated cholinesterase inhibitors: synthesis, biological activity, and molecular docking studies
(2024.01.01) Muglu, H.; Yakan, H.; Erdogan, M.; Topal, F.; Topal, M.; Turkes, C.; Beydemir, S.
Exploring novel frameworks for treating Alzheimer's disease is an ambitious objective. In this particular context, a range of asymmetric biscarbothioamide derivatives (3a-l) with varying substitutions have been meticulously designed and effectively synthesized. The newly synthesized compounds have all been definitively characterized using established spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, and elemental analysis. In vitro, all the derivatives (3a-l) were evaluated to assess their inhibitory potential against cholinesterase enzymes (acetylcholinesterase, AChE, and butyrylcholinesterase, BChE). The outcomes demonstrated that these derivatives were potent and exhibited selectivity in inhibiting AChE, except for compounds 3b and 3e, which specifically inhibited BChE, showcasing varying degrees of KI values. Significantly, compounds 3j (KIs of 11.91 +/- 2.25 nM for AChE and 77.76 +/- 8.02 nM for BChE) and 3h (KIs of 14.73 +/- 2.30 nM for AChE and 59.54 +/- 6.20 nM for BChE) emerged as the most potent dual inhibitors of AChE and BChE within the series, respectively, with KI constants even lower than those of the standard drug tacrine (KIs of 68.70 +/- 5.39 nM for AChE and 111.60 +/- 10.52 nM for BChE). Furthermore, their potential scavenging activity against DPPH and ABTS radicals was evaluated. To further validate the experimental findings, molecular docking studies were performed in silico to ascertain the binding modes of these compounds with the active pockets of AChE and BChE enzymes. Investigating innovative frameworks for addressing Alzheimer's disease is a challenging goal. In this specific scenario, a selection of asymmetric biscarbothioamide derivatives (3a-l) with different substitutions has been carefully formulated and successfully synthesized.
Schiff bases based on thio/carbohydrazide: Synthesis, spectroscopic characterization, DFT, antimicrobial, DNA interactions and cytotoxicity studies
(2024.01.01) Çavus, M.S.; Yakan, H.; Baskan, C.; Muglu, H.; Babacan, A.A.
New Schiff bases (1-8) have been prepared from numerous aldehydes and thio/carbohydrazide. The chemical structures of these compounds were characterized using IR, 1H NMR, 13C NMR spectroscopic methods, and elemental analysis. Electronic and spectroscopic properties of the compounds were determined by DFT calculations performed at the B3LYP/6-311++G(2d,2p) level of theory and were analyzed comparatively with experimental findings. The relationship between some global reactivity parameters and the nucleophilicelectrophilic attack abilities of the compounds and their antimicrobial and cytotoxic activities was also investigated. The antimicrobial effects of the synthesized compounds on microorganisms were screened using disc diffusion methods. According to the disc diffusion results, compound 8 in particular exhibits a high antibacterial potential against Bacillus cereus (15.66 +/- 0.57 mm). The interaction of synthesized compounds with pUC18 plasmid DNA was analyzed by the agarose gel electrophoresis method. The results showed that compounds 6, 7, and 8 interact with plasmid DNA and cause fragmentation of the Form I structure. In addition, in vitro, the cytotoxic activity of compounds on HT-29 (human adenocarcinoma colon) cell lines was investigated by the MTT method. Our study showed that compounds 7 and 8 have cytotoxic effects on HT-29 cell lines. The IC50 value was determined to be 96.93 mu M for compound 7 and 91.55 mu M for compound 8.
Synthesis, spectroscopic characterization, DFT studies and antioxidant activity of new 5-substituted isatin/thiosemicarbazones
(2025.01.01) Muglu, H.
A new series of thiosemicarbazone derivatives (1-8) were prepared and elucidated by FT-IR, 1H NMR, and 13C NMR spectroscopic methods and elemental analysis. In this study, in which the antiradical activities of 1,1diphenyl-2-picrylhydrazil (DPPH) were investigated, ascorbic acid was used as a reference antioxidant. Also, density functional theory (DFT) calculations were employed to investigate the structural and electronic properties of compounds, and the obtained data were utilized to elucidate antioxidant activity. In summary, the half maximal inhibitory concentration (IC50) values were calculated and had lower antioxidant activity than the standard ascorbic acid.
Synthesis, Theoretical, in Silico and in Vitro Biological Evaluation Studies of New Thiosemicarbazones as Enzyme Inhibitors
(2023.01.01) Erdogan, M.; Cavus, M.S.; Muglu, H.; Yakan, H.; Türkes, C.; Demir, Y.; Beydemir, S.
Eleven new thiosemicarbazone derivatives (1-11) were designed from nine different biologically and pharmacologically important isothiocyanate derivatives containing functional groups such as fluorine, chlorine, methoxy, methyl, and nitro at various positions of the phenyl ring, in addition to the benzyl unit in the molecular skeletal structure. First, their substituted-thiosemicarbazide derivatives were synthesized from the treatment of isothiocyanate with hydrazine to synthesize the designed compounds. Through a one-step easy synthesis and an eco-friendly process, the designed compounds were synthesized with yields of up to 95 % from the treatment of the thiosemicarbazides with aldehyde derivatives having methoxy and hydroxy groups. The structures of the synthesized molecules were elucidated with elemental analysis and FT-IR, H-1-NMR, and C-13-NMR spectroscopic methods. The electronic and spectroscopic properties of the compounds were determined by the DFT calculations performed at the B3LYP/6-311++G(2d,2p) level of theory, and the experimental findings were supported. The effects of some global reactivity parameters and nucleophilic-electrophilic attack abilities of the compounds on the enzyme inhibition properties were also investigated. They exhibited a highly potent inhibition effect on acetylcholinesterase (AChE) and carbonic anhydrases (hCAs) (K-I values are in the range of 23.54 +/- 4.34 to 185.90 +/- 26.16 nM, 103.90 +/- 23.49 to 325.90 +/- 77.99 nM, and 86.15 +/- 18.58 to 287.70 +/- 43.09 nM for AChE, hCA I, and hCA II, respectively). Furthermore, molecular docking simulations were performed to explain each enzyme-ligand complex's interaction.