Browsing by Author "Muğlu, H."

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Kinetic Insights into the Antioxidant Effect of Isatin-Thiosemicarbazone in Biodiesel Blends
(2024) Karakullukçu, N.T.; Muğlu, H.; Yakan, H.; Yılmaz, V.M.; Marah, S.; İnce, İ.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 and were calculated as 137-147 kJ mol and 173-183 kJ mol, respectively.
Kinetic Insights into the Antioxidant Effect of Isatin-Thiosemicarbazone in Biodiesel Blends
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Karakullukçu, N.T.; Muğlu, H.; Yakan, H.; Yılmaz, V.M.; Marah, S.; İnce, İ.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.
Schiff bases based on thio/carbohydrazide: Synthesis, spectroscopic characterization, DFT, antimicrobial, DNA interactions and cytotoxicity studies
(Elsevier B.V., 2024) Çavuş, M.S.; Yakan, H.; Başkan, C.; Muğlu, 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 nucleophilic-electrophilic 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 µM for compound 7 and 91.55 µM for compound 8.
Synthesis, structure elucidation, antioxidant properties, and theoretical calculations of new Schiff bases–isatin derivatives
(Springer Science and Business Media B.V., 2024) Bakır, T.K.; Çavuş, M.S.; Muğlu, H.; Yakan, H.
Isatin-derived Schiff bases are the subject of many studies, finding wide application areas in polymer technology, pharmaceutical industry, and medicine. In this study, a series of new Schiff bases were prepared from monothiocarbohydrazones based on isatins with different substituents (5-F, 5-Br, 5-I, and 5-MeO). The chemical structures of the synthesized compounds were determined using 1H NMR, 13C NMR, FTIR spectroscopic techniques, and elemental analysis. Antioxidant activity determinations of 23 compounds were performed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical quenching method. The highest percent inhibition value at 10 µM concentration was shown by compound number 22, 5-bromoisatin Schiff base containing 3-methoxy-4-hydroxy group. Compound 17, a 5-iodoisatin Schiff base containing 3-methoxy-4-hydroxy group, showed the highest antioxidant activity with an IC50 value of 9.76 ± 0.03 µM. In addition to the theoretical analysis of the compounds, both their spectroscopic and antioxidant properties were investigated. The ground-state geometries and some chemical reactivity parameters of the compounds were calculated using the B3LYP/6-311 + + G(2d,2p) approach. Besides intramolecular interactions, substituent effects, and some QTAIM parameters, the calculations were also performed to study the electronic properties of reactive N/O–H bonds and were used to interpret the experimental results. The effects of the electronic parameters and intramolecular interactions of reactive N/O–H bonds on the antioxidant properties of the compounds were investigated. Additionally, the relationships of DPPH reactions with delocalization indices of N/O-H bonds and the pattern of SET/HAT mechanisms with electronic variables were analyzed. Examination of electron and hydrogen atom transfer mechanisms has shown the dominance of electron transfer, supported by the correlation coefficients between IC50 values and SET reaction energies.
Synthesis, theoretical, in silico and in vitro biological evaluation studies of new thiosemicarbazones as acetylcholinesterase and carbonic anhydrases inhibitors.
(2023-09-28) Erdogan, M.; Çavus, S.; Muğlu, H.; Yakan, H.; Türkeş, C.; Demir, Yeliz; Beydemir, Şükrü
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 hydroxyl groups. The structures of the synthesized molecules were elucidated with elemental analysis and FT-IR, 1H NMR, and 13C 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. They exhibited a highly potent inhibition effect on acetylcholinesterase (AChE) and carbonic anhydrases (hCAs) (KI 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.
Synthesis, Theoretical, in Silico and in Vitro Biological Evaluation Studies of New Thiosemicarbazones as Enzyme Inhibitors
(John Wiley and Sons Inc, 2023) Erdoğan, M.; Cavus, S.M.; Muğlu, 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, 1H-NMR, and 13C-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) (KI 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.