Browsing by Author "Bulut, Onur"

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Citation - WoS: 4
Citation - Scopus: 5
Antioxidant Activity of Micractinium Sp. (Chlorophyta) Extracts Against H2O2 Induced Oxidative Stress in Human Breast Adenocarcinoma Cells
(Nature Portfolio, 2024) Bulut, Onur; Kose, Iskin Engin; Sonmez, Cagla; Oktem, Huseyin Avni
In response to the growing demand for high-value bioactive compounds, microalgae cultivation has gained a significant acceleration in recent years. Among these compounds, antioxidants have emerged as essential constituents in the food, pharmaceutical, and cosmetics industries. This study focuses on Micractinium sp. ME05, a green microalgal strain previously isolated from hot springs flora in our laboratory. Micractinium sp. cells were extracted using six different solvents, and their antioxidant capacity, as well as total phenolic, flavonoid, and carotenoid contents were evaluated. The methanolic extracts demonstrated the highest antioxidant capacity, measuring 7.72 and 93.80 mu mol trolox equivalents g-1 dry weight (DW) according to the DPPH and FRAP assays, respectively. To further characterize the biochemical profile, reverse phase high-performance chromatography (RP-HPLC) was employed to quantify twelve different phenolics, including rutin, gallic acid, benzoic acid, cinnamic acid, and beta-carotene, in the microalgal extracts. Notably, the acetone extracts of Micractinium sp. grown mixotrophically contained a high amount of gallic acid (469.21 +/- 159.74 mu g g-1 DW), while 4-hydroxy benzoic acid (403.93 +/- 20.98 mu g g-1 DW) was the main phenolic compound in the methanolic extracts under heterotrophic cultivation. Moreover, extracts from Micractinium sp. exhibited remarkable cytoprotective activity by effectively inhibiting hydrogen peroxide-induced oxidative stress and cell death in human breast adenocarcinoma (MCF-7) cells. In conclusion, with its diverse biochemical composition and adaptability to different growth regimens, Micractinium sp. emerges as a robust candidate for mass cultivation in nutraceutical and food applications.
Antioxidant Activity of Micractinium Sp. (Chlorophyta) Extracts Against H2o2 Induced Oxidative Stress in Human Breast Adenocarcinoma Cells
(Nature Portfolio, 2025) Bulut, Onur; Kose, Iskin Engin; Sonmez, Cagla; Oktem, Huseyin Avni
Synthesis, Photophysical Properties, and Photodynamic Therapy Efficacies of Meso-Pyridine Bodipys and Their Ruthenium Complexes
(Wiley, 2025) Aksoy, Burcu Topaloglu; Ozcan, Emrah; Bulut, Onur; Kazan, Hasan Huseyin; Cosut, Bunyemin
Photodynamic therapy (PDT) is a candidate approach for cancer treatment. In PDT applications, a fluorescent molecule, called photosensitizer (PS), induces light-directed production of reactive species, resulting in cytotoxicity. Having tunable fluorescence and easy derivatization properties, the BODIPY core is widely used as a PS. To further increase the light-induced toxicity, studies have shown the conjugation of heavy metals to the BODIPY core. However, such complexes are still needed to fully figure out their potential. In the current study, as part of an ongoing one, two novel ruthenium-BODIPY complexes were synthesized and characterized by structural, photophysical, and biological methods. To obtain complex structures between ruthenium dimers and BODIPY units, [RuCl2(p-cymene)](2) dimers, and non-iodo and di-iodo BODIPY derivatives were reacted in methanol-tetrahydrofuran (THF) medium. Photophysical properties, fluorescence lifetime, molar extinction coefficient, photostability, and capability of singlet oxygen generation were determined using absorption and/or fluorescence spectroscopy. Besides, the structures of the complexes were further clarified by the single-crystal X-ray technique. The cytotoxicity of compounds was examined against the human cervical cancer cell line, HeLa, and breast cancer cell line, MDA-MB-231, both in the dark and by light irradiation. Accordingly, both precursors and their ruthenium complexes were light-dependent toxic; nevertheless, di-iodinated meso-pyridine-substituted BODIPYs displayed light-independent toxicity by long-term treatments. Moreover, the effects of the complexes were cell-specific and the toxicities of di-iodinated BODIPY complexes were inversely correlated with the concentrations, underlying a possible aggregation and/or unpredicted cellular interaction pattern. These results emphasize that further functionalization and molecular characterization of BODIPY-ruthenium complexes are still required for PDT applications.