Siirt Üniversitesi Kurumsal Akademik Arşivi
DSpace@Siirt, Siirt Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Bioactive Apigenin‐7‐O‐β‐Glucoside and Rosmarinic Acid Molecules From Two Nepeta Species: Bioactivity‐Guided Isolation, In Vitro Evaluations, Pharmacokinetic and In Silico Approaches as Metabolic Enzyme Inhibition Agents
(Wiley, 2025-04-27) Mesut Gok; Yunus Basar; Semiha Yenigun; Yasar Ipek; Lutfi Behcet; Tevfik Ozen; Ibrahim Demirtas
Introduction: In this study, apigenin-7-O-β-glucoside (AGL) was isolated from Nepeta nuda; also, rosmarinic acid (RA) was isolated from N. aristata and N. nuda.
Objectives: The aim of this study is to investigate the enzyme inhibitory, DNA protective, and antibacterial effects of AGL and RA isolated from two Nepeta species.
Material and methods: 1D and 2D NMR spectra and an MS chromatogram were recorded to identify AGL and RA. The antibacterial and DNA protection activities, enzyme inhibition, and kinetics investigated of AGL and RA. Molecular interactions, molecular dynamics (MD) simulations, molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations, density functional theory (DFT), molecular electrostatic potential (MEP) analyses, and prediction of activity spectra for substances (PASS) predictions for RA and AGL were investigated for the first time to evaluate the activity results.
Results: In this context, the inhibitory properties of AGL were higher in urease, α-amylase, and tyrosinase, whereas RA has a higher inhibitory activity on lipase, CA, and urease. In addition, AGL and RA showed effective antimicrobial activity against Staphylococcus aureus, while it also was effective DNA and deoxyribose protective activities. The stability of the complex formed by lipase, CA, and urease with RA and by tyrosinase and α-amylase with AGL was determined by MD simulations, and the energy results of RA were evaluated by MM-PBSA analysis. The DFT, MEP analysis, and PASS prediction showed that AGL and RA have a soft structure and can easily exchange electrons.
Conclusion: According to the results obtained from the current study, AGL and RA were explored as a drug model.
Comparison of Xanthine Oxidase Inhibitory Activities and Phenolic, Fatty Acid, Element, and Vitamin Levels of Four Mushroom Species
(Wiley, 2025-04) Suat Ekin; Mahire Bayramoglu Akkoyun; Ahmet Bakir; Mustafa Emre Akcay; Emre Can Ekin
The purpose of this study was to determine the antioxidant properties and the composition of phenolic compounds, trace elements, vitamins, and fatty acids in the edible mushrooms Helvella leucopus, Tricholoma terreum, Lepista nuda, and Marasmius oreades, as well as their inhibitory effect on xanthine oxidase. Elemental analyses were conducted using ICP-OES. Phenolic compounds and vitamins were performed by HPLC, while identification of fatty acids was performed by GC-MS. HPLC analysis revealed the phenolic compounds in H. leucopus, T. terreum, L. nuda, and M. oreades, with gallic acid being the main compound identified, with levels of 133.04, 246.49, 408.64, and 129.302 μg/g dry weight, respectively. For vitamins, α-tocopherol is the most primary vitamin found with values of 0.6009, 0.79, and 0.3581 μmol/kg dw. GC-MS analysis determined that the fatty acids with linoleic acid are the major fatty acids identified, with percentages of 30.82%, 19.92%, 30.38%, and 20.86%. ICP-OES measurement indicated that trace elements with iron as the dominant trace element were observed, with concentrations of 0.248, 0.237, 0.449, and 0.1998 mmol/kg dw. The XO inhibitory activities of four mushrooms were assayed, with the IC50 values of 39.97, 20.71, 11.71, and 23.85 μg/mL, respectively. L. nuda and T. terreum may be effective for hyperuricemia and gout, which is associated with the results of phenolic compounds, some vitamins, trace elements, and linoleic acid contents on the inhibitory activities against xanthine oxidase. The results of medicinal mushrooms have shown that they could potentially be useful as inhibitors for the prevention of XO-related diseases induced by ROS.
Subclinical Pregnancy Toxemia Affects Blood Parameters of Ewes and Impairs Postnatal Growth and Development of Lambs
(Wiley, 2025-04-22) Ali Osman Turgut; Mürsel Küçük; Mehmet Irmak; Cahit Özcan; Davut Koca; Erman Gülendağ; Muhammed Furkan Önen; Rahmi Doğan; Ali Ünver; İbrahim Halil Keskin
Pregnancy toxemia (PT) is a common metabolic disorder that occurs in the last trimester of pregnancy. This study aimed to detect the effects of subclinical PT (SPT) on serum biochemical parameters of ewes and postnatal growth and development of lambs in Romanov sheep. A total of 40 ewes and 69 lambs were included in the study. Blood samples of ewes were collected at the time of parturition to evaluate serum beta-hydroxybutyric acid (βHBA), serum nonesterified fatty acid (NEFA), cholesterol, and triglyceride. Live weight and body measurements of lambs were recorded at birth (0th day), 30th day, and 60th (weaning) day. In the diagnosis of SPT serum βHBA concentrations were taken into account. A cut-off value of 0.8 mmol/L for βHBA was a critical concentration and ewes with 0.8-1.6 mmol/L βHBA were evaluated as SPT. There were no ewes with ΒHBA value higher than 1.6 mmol/L (clinical PT) in the study. There was no significant difference in serum βHBA, NEFA and cholesterol concentrations between ewes regarding birth type (single, twin, and triplet). However, triglyceride concentrations were higher (p < 0.001) in ewes giving birth to triplets compared to ewes giving birth to single lamb. Serum βHBA and triglyceride concentrations were higher (p < 0.01) in ewes with SPT (n = 14) compared to healthy ewes (n = 26). There was no significant difference between ewes with SPT and healthy ewes in serum NEFA and cholesterol. Repeated measures ANOVA results indicated that SPT negatively affected 0th, 30th, and 60th body weights of twin (p < 0.01) and triplet born lambs (p < 0.05). The effect of time on body weights was also found to be significant (p < 0.001). Similarly, most of the body measurements of twin and triplet born lambs were lower (p < 0.05) in the SPT group compared to healthy group. Overall results indicate that SPT may negatively affect postnatal growth and development in Romanov lambs. Because a decline in growth performance has many negative outcomes affecting production traits in sheep, these findings may be valuable for the veterinary field.
Spatio-temporal patterns and Turing–Hopf bifurcation in a spatially extended prey–predator model with ratio-dependent interactions
(Springer Science and Business Media LLC, 2025-04-16) Muhammad Waqas Yasin; Nauman Ahmed; Ali Akgül; Muhammad Zafarullah Baber; Dumitru Baleanu; Ovidiu Tintareanu-Mircea
In this manuscript, we investigate the (2+1)-dimensional ratio-dependent prey–predator system. Prey–predator dynamics are a vital component of the eco-system. It provides the basic food for the living organisms. So, we considered the extended prey–predator model. The underlying model has 2 equilibrium points and stability analysis is carried out about the coexistence equilibrium. The condition for the Hopf bifurcation and Turing instabilities are derived. These conditions help to analyze the formation of patterns in the prey–predator system. The dispersion relation shows the changing behavior of Hopf bifurcation and Turing instability from stable to unstable. The bifurcation and Turing instability simulation divide the parametric space into 4 Regions. In Region I, the solution is stable, in Region II there is purely Turing instability, in Region III, there is only Hopf instability and in Region IV there is Hopf as well as Turing instability. Different types of Turing patterns are produced to capture rate parameters. The numerical solution of the model is obtained by positivity preserving finite difference scheme. The applied scheme is von Neumann stable, and consistent with the model. The bounded behavior of a given scheme is established. Mainly, we are focused on the graphical simulations for pattern formation and steady-state analysis. The 3D and 2D visualization for the Turing pattern and numerical solution are drawn for the various parameter values. The numerical simulations endorsed the analytical results.
Enhancing low-temperature ethanol-selective catalytic reduction over Ag/TiO2-cordierite catalysts via cerium addition
(Springer Science and Business Media LLC, 2025-04-19) Himmet Ozarslan; Ali Keskin; Ibrahim Aslan Resitoglu
The purpose of this study is to investigate the NOx reduction activity of Ag/TiO2-Cordierite catalysts enhanced with cerium (Ce) under varying operational temperatures and engine loads. The aim is to improve the low-temperature activity of the catalyst in an ethanol-selective catalytic reduction system using real exhaust gases. During the catalyst production process, Ag and Ce were used as active components, TiO2 as the secondary support material, and cordierite as the primary carrier structure material. Catalysts with 1 wt%, 3 wt%, and 5 wt% Ce-doped Ag/TiO2/Cordierite were synthesized using the washcoating method and characterized through X-Ray Diffraction, Brunauer–Emmett–Teller analysis, and Scanning Electron Microscopy (SEM). Performance test results demonstrated that the NOx conversion rates of the Ce-doped catalysts exceeded 90% at 300 °C and a space velocity of 40,000 h⁻1. Notably, the highest NOx conversion rate of 92.48% was achieved with the 5% Ce-Ag/TiO2/Cordierite catalyst. These findings indicate that the incorporation of Ce into Ag/TiO2/Cordierite catalysts significantly enhances NOx conversion activity at low temperatures in the ethanol-SCR system.
