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    A potential DNA protector, enzyme inhibitor and in silico studies of daucosterol isolated from six Nepeta species
    (Elsevier Sci Ltd, 2024) Yenigun, Semiha; Basar, Yunus; Ipek, Yasar; Gok, Mesut; Behcet, Lutfi; Ozen, Tevfik; Demirtas, Ibrahim
    Daucosterol (DAU) was isolated from the methanol-chloroform crude extract of six Nepeta species (N. N. aristata, , N. baytopii, N. italica, N. nuda albiflora, N. stenantha and N. trachonitica) ) using sephadex and silica-gel columns via bioactivity-guided isolation. Spectroscopic methods and comparisons with similar data in the literature determined its structure. DAU was evaluated for enzyme inhibitions, kinetics, DNA protection, and molecular interactions. The inhibition activities of AChE, tyrosinase, BChE, and urease were found to be 21.32+1.24, 3.17 +0.45, 16.73+0.10 and 12.95+0.21 mu M, respectively. The Ki i values of the inhibition kinetics of the same enzymes were observed as 0.11, 0.05, 0.12, and 0.12 mM, respectively. DAU exhibited effective protection activity against DNA damage induced by H2O2 and ultraviolet radiation in DNA protection tests. DFT analysis showed low hardness and high softness values. The best binding affinity of DAU was achieved by the enzymes AChE and BChE (for both:-9.90 kcal/mol). As a result of the interaction of standards and DAU with enzymes, it was observed that DAU bound with a higher potential than the standards. Molecular dynamics simulations of these enzymes were examined for 100 ns, and the energy results of the simulation were determined by MM/PBSA calculation in the last 10 ns. Additionally, its pharmacokinetic properties were investigated with SwissADMET, and it was noted that it had low toxic effects and gastrointestinal absorption. Thus, in vitro and in silico analysis determined that the DAU molecule could protect against DNA oxidative damage and an active metabolic enzyme inhibitor.
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    Chloroform-Methanol Extraction Antimicrobial Potential of Rheum Ribes Originating from Elazig/Aricak Province
    (2023) Özdemir, Oğuzhan; Gok, Mesut; Toy, Nurten; Tuzcu, Zeynep
    Rheum ribes (R. ribes) has a variety of medicinal applications due to the presence of anthraquinone derivatives and other compounds. It was aimed to determine the potential antimicrobial effects on some gram-negative/positive pathogens, and lactic acid bacteria by agar well diffusion test following minimum inhibition concentrations (MIC) with liquid extract samples of R. ribes. Growth concentrations of R. ribes extract doses (14.17-0,89 mg/L) were applied to indicator microorganisms. MIC method used microbial density values compared to the control group. Result of the Agar well diffusion test, the best antibacterial effects were detected on L. monocytogenes and S. aureus and following B. subtilis (zone diameter of 18.72 and 18.32 mm, respectively). The R. Ribes extract showed a higher inhibitor effect than tetracycline antibiotic against L. monocytogenes. Similarly, S. aureus and E. faecalis., S. paratyphi A were more affected by R. Ribes extract than tetracycline antibiotic. The MIC test result, the highest inhibitory effects of R. ribes extract at a concentration of 0,89 mg/L for S. Paratyphi A strain, 3.54 mg/L for K. pneumonia, and 3.54 mg/L for E. coli RSSK 09036 were determined as 50.81%, 60.45%, and 60.40%, respectively. The highest inhibition effects of R. ribes at 14.17 mg/L (0.5 dilution concentration) concentration were determined at the rate of 80.12% for Bacillus clausii and 96.04% for B. subtilis. In the present study, it is thought that the differences between the antimicrobial effect and MIC tests seen in gram-positive, negative and probiotic bacteria may be related to the surface tension effect of the extract
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    Evaluation of the antioxidant properties and total phenolic content of a dairy product (yogurt) supplemented with Thymus willdenowii essential oil from Algeria
    (Springer, 2022) Benguedouar, Karima; Betina, Soumeya Bencharif; Erenler, Ramazan; Genc, Nusret; Gok, Mesut; Sebti, Mohamed; Madi, Nassim
    The purpose of this study was to evaluate the antioxidant properties and total phenolic content of a dairy product (yogurt) supplemented with Thymus willdenowii (synonym: Thymus hirtus) essential oil. The evaluation of the antioxidant and antibacterial activities of the oil against food spoilage bacteria and lactic acid strains was also assessed. The chemical composition of the oil was obtained by GC/MS. The evaluation of the antioxidant activity of a fortified yogurt with this oil was assessed by Oxygen radical absorbance capacity test (ORAC). The main component of the oil was Linalool (89.55%). DPPH, and Ferric reducing power revealed a weak antioxidant activity (IC50 > 1600 mu g/mL, > 800 mu g/mL respectively) while a moderate activity was obtained with ABTS and CUPRAC tests (38.06 +/- 0.30, 56.15 +/- 1.07 mu g/mL respectively). A high concentration of the oil is needed to delay the inhibition of the beta-carotene (> 800 mu g/mL). Thus, a strong antibacterial activity was observed against the pathogenic strains with the high inhibition diameter for B.cereus ATCC10876 (31.75 +/- 1.50 mm) while a weak effect was observed against lactic acid bacteria. A significant decrease in the antioxidant potential of non-supplemented yogurt was observed from day 1 to 21 while there was no significant difference in ORAC of supplemented yogurt with the oil. The maximum of total phenolic content was observed in day 21 of cold storage (252.92 +/- 3.01 mu g GAE/mL of yogurt). The essential oil studied could be an effective natural additive to yogurt avoiding the use of synthetic preservatives.
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    In Vitro Bioactivities and In Silico ADME Profile for Potential Biological Target Prediction of Selected Phytochemicals Using Six Nepeta Species
    (Wiley-V C H Verlag Gmbh, 2024) Yenigun, Semiha; Basar, Yunus; Gul, Fatih; Ipek, Yasar; Gok, Mesut; Behcet, Lutfi; Ozen, Tevfik
    Several Nepeta species, used in traditional uses, represent sources of valuable phytochemical composition, as well as in vitro biological and in silico clinical activities. In the present study, the antioxidant and DNA protective properties of methanol: chloroform (1 : 1) extracts of six Nepeta species were evaluated by comparison with standards. In HPLC-MS/MS analysis, the main components of the extracts were identified as rosmarinic acid, caffeic acid, chlorogenic acid, shikimic acid, and scutellarin. In the GC-FID analysis, the highest components were palmitate and cis-11-eicosenoic acid. N. aristata has the greatest total phenol and flavonoid contents. N. baytopii, N. aristata, N. italica, N. stenantha, and N. nuda exhibited the highest antioxidant activities. The N. nuda, N. aristata, N. italica, and N. trachonitica extracts were shown to have the most potent DNA protection activity. According to the result of the GC-FID and HPLC-MS/MS analysis of Nepeta extracts, ADMET studies of the main components of the extracts were performed. It was evaluated that palmitic acid had BBB permeability, but oleic acid was toxic. The in vitro and in silico results confirmed that Nepeta L. extracts are potential natural products.