Yazar "Demirtas, Ibrahim" seçeneğine göre listele

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    Öğe
    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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    Öğe
    Activation and inhibition effects of some natural products on human cytosolic CAI and CAII
    (Springer Birkhauser, 2019) Adem, Sevki; Akkemik, Ebru; Aksit, Huseyin; Guller, Pinar; Tufekci, Ali Riza; Demirtas, Ibrahim; Ciftci, Mehmet
    Carbonic anhydrases (CAs) play a significant function in diverse pathological and physiological processes. Their inhibitors and activators are suitable molecules to use as a drug in the treatment of different disease. In the present study, seven natural compounds, namely didymin, retusin isoquercitrin, silymarin, verbascoside, teucroside, and 3'-O-methylhypolaetin 7-O-[6'-O-acetyl-beta-D-allopyranosyl-(1 -> 2)]-6 ''-O-acetyl-beta-D-glucopyranoside were isolated from Mentha spicata, Sideritis libanotica linearis, Platanus orientalis, Teucrium chamaedrys subsp. chamaedrys, and Silybum marianum. The influences of compounds on the carbonic anhydrase I(hCAI) and II(hCAII) purified from human erythrocytes were tested. Five phenolic compounds acted as an inhibitor on the activity of hCAI, and IC50 values were computed between 18.16 and 172.5 mu M. Isozyme hCAII is only inhibited by silymarin with an IC50 value of 43.12 mu M. This isoenzyme was effectively activated by five natural compounds with AC(50) values in the range of 2.98-18.53 mu M. To understand the binding patterns of molecules that show activation effect against hCAII, molecular docking was done using Leadit 2.3.2 software, and calculated between -19.05 and -14.42 (kJ/mol) binding energies. Both in vitro and in silico results demonstrated that the best activators against hCAII were teucroside and isoquercitrin, with AC(50) values of 2.98 and 3.17 mu M, and binding energies -19.05 and -18.01 (kJ/mol), respectively. According to the ADME results, retusin demonstrated physicochemical and pharmacokinetic properties specific to the drug candidates.