Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Investigation on the Bioactive Secondary Metabolites of the Endophytic Fungus Penicillium Roseopurpureum(01. Izmir Institute of Technology, 2022) Dizmen, Berivan; Bedir, ErdalIn recent years, endophytic fungi have been considered as significant resources of new bioactive secondary metabolites, so they are predicted to have an important impact in drug discovery and development. In our preliminary study, the chemical diversity and cytotoxic activity of an endophytic fungus, namely Penicilium roseopurpureum 1E4BS1 isolated from Astragalus angustifolius, have been demonstrated. Based on these data, it was aimed to obtain bioactive secondary metabolites of P. roseopurpureum 1E4BS1 within the scope of this thesis. Firstly, a fermentation study was carried out in a rotary shaker at 180 rpm, 25 ºC for 20 days, and the obtained broth was extracted with EtOAc. Secondly, nine metabolites were isolated from the EtOAc extract by chromatographic methods, and the structures of compounds were elucidated by spectral methods (1D-, 2D NMR, and MS). The structure elucidation studies revealed that seven metabolites had anthraquinone backbone, whereas two compounds were found to be derivatives of curvularin from macrolide group. A chemical structure search confirmed that five of the metabolites were new for nature. Cytotoxic activity of the compounds and the EtOAc extract was tested against three cancer (DU145, LnCaP, and PC3) and normal (RPWE-1) cell lines by MTT cell viability assay. The metabolite PR-EB-01 exhibited the highest activity with IC50 values of 26.0, 37.2, 24.7, and 30.9 μM against LNCaP, PC3, DU145, and RPWE-1 cells, respectively.Master Thesis Fungal Biotransformation of Novel 20(27)- Octanor Cycloastragenol and Biological Activities of the Purified Metabolites(Izmir Institute of Technology, 2019) Duman, Seda; Bedir, Erdal; Çağır, AliBiotransformation is the chemical modifications performed by enzymes or living organisms. The difficulty and high cost of enzyme isolation and purification makes it more advantageous to use whole cell systems as biocatalysts. Microbial biocatalysts are particularly interesting in the modification of complex molecules such as steroids and triterpenoids, which can catalyze stereo- and regio- selective reactions that are difficult or impossible to perform with chemical reactions. Specially, ability of endophytic microorganisms to produce specific enzymes for adaptation to their environment by tolerating toxic defense metabolites, makes them interesting for biotransformation studies. Telomeres are nucleotide structures located at the end of chromatids shortening with each cell division. Telomerase is a reverse transcriptase enzyme, and it helps to replenish telomere ends that are truncated by aging and stress factors. The telomerase activators (TA) with their potentials are suggested encouraging agents for healthy aging, and they are projected to generate a huge market in the future. Cycloastragenol is the only natural product in the sector marketed as a potent telomerase activator. In this study, by using endophytic fungi, the biotransformation studies were performed on 20(27)-octanor cycloastragenol. As a result, 14 biotransformation products, were isolated by chromatographic studies, and the structures of the metabolites were established by spectral methods. Based on the literature survey, 13 compounds turned out to be new for nature. Seven metabolites were screened for telomerase activation. In these screenings, metabolites showed telomerase activation ranging from 5.43 to 12.36 fold at doses ranging from 0.1 to 30 nM compared to the control cells treated with DMSO.