Browsing by Author "Yaprak, Ahmet Emre"

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Analysis of Taxonomic and Geographic Patterns of Turkish Veronica Orientalis Using Nuclear and Plastid Dna and Morphological Data
(Springer Wien, 2014) Sonibare, Mubo A.; Armagan, Metin; Ozgokce, Fevzi; Yaprak, Ahmet Emre; Mayland Quellhorst, Eike; Albach, Dirk C.
Veronica orientalis and related species form one of the taxonomically most challenging subgroups within the genus Veronica. Hybridization and polyploidization on the one hand and convergent character evolution on the other have made delimitation of species difficult. Amplified fragment length polymorphisms and plastid DNA markers were used in conjunction with 54 morphological characters to study relationships among 35 accessions of V. orientalis Mill. as well as other closely related species of Veronica occurring in Turkey and adjacent areas of Georgia and Armenia. In addition, ploidy levels were estimated for 15 accessions using flow cytometry. Diploid to hexaploid individuals were detected in V. orientalis. Analysis of DNA markers demonstrated the non-monophyly of V. orientalis, especially with regard to V. fuhsii and V. multifida from Eastern Turkey, but nuclear and plastid DNA markers are largely incongruent. Neither demonstrates a clear biogeographic pattern. The morphological analysis reveals the distinction of V. orientalis subsp. carduchorum, which is weakly retrieved in some molecular analyses and some clustering according to geography. V. multifida is not monophyletic likely due to parallel evolution of pinnatifid leaves east and west of the Anatolian diagonal.
Modulation of Mrna Expression and Activities of Xenobiotic Metabolizing Enzymes, Cyp1a1, Cyp1a2, Cyp2e1, Gpx and Gstp1 by the Salicornia Freitagii Extract in Ht-29 Human Colon Cancer Cells
(inst Bioloska Istrazivanja Sinisa Stankovic, 2017) Altay, Ahmet; Kartal, Deniz Irtem; Sadi, Gokhan; Guray, Tulin; Yaprak, Ahmet Emre
Phase I-II detoxification and antioxidant enzymes are responsible for the detoxification and elimination of activated carcinogens, acting as important biomarkers for chemoprevention. Among them, cytochrome P450s plays a prominent role in the metabolic activation of xenobiotics. The herb Salicornia freitagii (SF) (Amaranthaceae) is known for its anticancer, antioxidant, antidiabetic and antiinflammatory activities. In this study, we determined the bioactive phenolics in the SF methanol extract and investigated its antiproliferative potential in HT-29 human colon cancer cells. We also investigated the modulation of some phase I and II enzyme (CYP 1A1, 1A2, 2E1, GSTP1 and GPx) mRNA expression and enzymatic activities by the SF extract and its major bioactive phenolic compounds. LC/MS-MS analysis showed that the main phenolic compounds of the methanolic SF extract are vanillic acid (48 mu g/100g) and p-coumaric acid (10.8 mu g/100g). SF extract, vanillic acid and p-coumaric acid exhibited high antiproliferative activities in HT-29 cells, with IC50 values of 81.79 mu g/mL, 98.8 mu M and 221.6 mu M, respectively. The mRNA expression levels of CYP1A2 and CYP2E1 were decreased, while those of GSTP1 and GPx in HT-29 cells were increased after application of either the SF extract or vanillic acid. The SF extract by itself also increased the activities of GPx and GSTP1 enzymes 1.68- and 1.49-fold, respectively. Our data indicate that the SF extract and its major bioactive compound, vanillic acid, could exert a modulatory effect on the expression of enzymes that are involved in xenobiotic activation and detoxification pathways in the gastrointestinal tract. For this reason, SF can be considered as a natural source of chemopreventive agents.