Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Lipoxygenase Inhibitory Activity Evaluation of Achillea Biebersteinii Afan. by Activity-Guided Fractionation(Elsevier Ireland Ltd, 2026) Subasi, Bilgen; Gunbatan, Tugba; Gurbuz, Ihan; Dilmac, Elif; Bedir, Erdal; Demirci, FatihEthnopharmacological relevance: Achillea biebersteinii Afan. is traditionally utilized as folk medicine for a broad range of therapeutic applications, especially for promoting the maturation of abscesses, wound healing; against inflammation, and rheumatism in T & uuml;rkiye. Aim of the study: The anti-inflammatory potential of A. biebersteinii was evaluated through activity-guided fractionation (AGF) targeting lipoxygenase (15-LOX) inhibition. Materials and methods: Different chromatographic techniques were used for the AGF of the ethyl acetate extract of A. biebersteinii aerial parts. The in vitro 15-LOX inhibitory activity evaluation was performed to address the antiinflammatory activity. The structures of purified compounds from the fractions were confirmed by LC-HRMS, 1H NMR, and 13C NMR analyses, respectively. Results: The fractionation and isolation process culminated in the identification of three key flavonoids namely; patulitrin, axillarin, quercetagetin-7-O-beta-glucopyranoside, and 4,5-dicaffeoylquinic acid, which showed statistically remarkable 15-LOX inhibitory activity with inhibition rates of 82.27%, 96.81 %, 84.65% and 77.47 %, respectively. Two flavonoids were isolated by using the AGF method, where quinic acid was spotted to have significant 15-LOX inhibitory activity. Conclusion: These findings support the future therapeutic potential of A. biebersteinii as a natural antiinflammatory source.Article Semi-Synthetic Sapogenin Derivatives Inhibit Inflammation-Induced Tumorigenic Signaling Alterations in Prostate Carcinogenesis(Elsevier Science Inc, 2026) Debelec-Butuner, Bilge; Ozturk, Mert Burak; Tag, Ozgur; Akgun, Ismail Hakki; Bedir, ErdalProstatic inflammation plays a pivotal role in prostate cancer development and progression via altering key cellular mechanisms, including proliferation, metastasis, and angiogenesis. Therefore, the use of antiinflammatory drugs could provide a valid contribution to PCa prevention and treatment. In our research, we explored semi-synthetic derivatives of cycloastragenol (CA) and astragenol (AG) to assess their potential to inhibit inflammation-mediated tumorigenic signaling. Building on our previous findings, which demonstrated their inhibitory activity on NFxB, we discovered that these molecules also suppress inflammation-induced cell proliferation and migration through distinct mechanisms. They effectively alleviated inflammation by reducing levels of ROS, NO, and VEGF expression. Furthermore, these molecules partially restored the expression of AR and the tumor suppressor NKX3.1, both of which are critical in prostate tumorigenesis within an inflammatory microenvironment. They also reversed inflammation-induced activation of Akt and (3-catenin signaling, suggesting their potential to inhibit inflammation-related prostate tumorigenesis. Our study further demonstrated that these molecules exhibited dose-dependent effects on inducing cell cycle arrest and apoptosis, as evidenced by increased p21 and decreased BCL-2 protein levels, leading to activated cell death and suppressed cellular migration. In conclusion, these semi-synthetic sapogenol derivatives demonstrate significant potential as antiinflammatory and anticancer agents, offering a promising approach for targeting prostatic inflammation and inflammation-driven prostate carcinogenesis.Book Part Astragalus sp.(CRC Press, 2023) Yakuboğulları, Nilgün; Bedir, ErdalAstragalus is one of the largest genera in Turkey and is widely distributed worldwide. The phytochemical studies on Turkish Astragalus species have presented 112 new compounds besides 63 known compounds. The overriding basis for biological activity studies is the traditional use of Astragalus roots in the Southeastern Region of Turkey to cure leukemia. As the isolated compounds did not show cytotoxic properties, a hypothesis that the biological activity of Astragalus saponins might result from the activation of the immune system came up. While Astragalus polysaccharides are used for their strong immunomodulatory activities in Chinese medicine, there are a few articles revealing the immunostimulatory properties of Astragalus saponins. Here, we summarized the compounds isolated from Turkish Astragalus species and concentrated on the immunomodulatory activities of these compounds to put forward their potential as saponin-based vaccine adjuvants. © 2024 selection and editorial matter, Ufuk Koca-Caliskan; individual chapters, the contributors.Article Citation - WoS: 19Citation - Scopus: 21Telomerase Activators From 20(27)-Octanor Via Biotransformation by the Fungal Endophytes(Academic Press, 2021) Duman, Seda; Ekiz, Güner; Yılmaz, Sinem; Yusufoğlu, Hasan; Ballar Kırmızıbayrak, Petek; Bedir, ErdalCycloastragenol [20(R),24(S)-epoxy-3 beta,6 alpha,16 beta,25-tetrahydroxycycloartane] (CA), the principle sapogenol of many cycloartane-type glycosides found in Astragalus genus, is currently the only natural product in the anti-aging market as telomerase activator. Here, we report biotransformation of 20(27)-octanor-cycloastragenol (1), a thermal degradation product of CA, using Astragalus species originated endophytic fungi, viz. Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae and Camarosporium laburnicola. Fifteen new biotransformation products (2-16) were isolated, and their structures were established by NMR and HRESIMS. Endophytic fungi were found to be capable of performing hydroxylation, oxidation, ring cleavage-methyl migration, dehydrogenation and Baeyer-Villiger type oxidation reactions on the starting compound (1), which would be difficult to achieve by conventional synthetic methods. In addition, the ability of the metabolites to increase telomerase activation in Hekn cells was evaluated, which showed from 1.08 to 12.4-fold activation compared to the control cells treated with DMSO. Among the compounds tested, 10, 11 and 12 were found to be the most potent in terms of telomerase activation with 12.40-, 7.89- and 5.43-fold increase, respectively (at 0.1, 2 and 10 nM concentrations, respectively).Article Citation - WoS: 12Citation - Scopus: 12Isolation of Rosmarinic Acid and Methyl Rosmarinate as Lipoxygenase Inhibitors From Salvia Palaestina Benth. by Activity-Guided Fractionation(Elsevier, 2021) İçen, Mehmet Sina; Gürbüz, İlhan; Bedir, Erdal; Günbatan, Tuğba; Demirci, FatihSalvia palaestina aqueous and methanol extracts were prepared from the aerial parts, which were evaluated for the in vitro anti-inflammatory properties using the lipoxygenase (LO) enzyme inhibition assay. While the aqueous extract showed no activity at test concentrations, a significant (p < 0.001) lipoxygenase inhibition was detected for the methanol extract with 29% inhibition. Activity guided fractionation was carried out on the methanol extract via liquid-liquid partitioning using n-hexane, dichloromethane, ethyl acetate, and n-butanol. The ethyl acetate fraction showed statistically the best inhibition among the sub-fractions with 70% inhibition (p < 0.0001). The compounds responsible for the activity were purified, and their structures were established as rosmarinic acid, and methyl rosmarinate by spectroscopic methods. IC50 values of rosmarinic acid, and methyl rosmarinate were calculated as 0.21 and 0.02 ?M, respectively. In conclusion, the in vitro anti-inflammatory potential of S. palaestina was associated to rosmarinic acid, and methyl rosmarinate, for the first time to the best of our knowledge. © 2021 SAABArticle Citation - WoS: 5Citation - Scopus: 7Five New Cardenolides Transformed From Oleandrin and Nerigoside by Alternaria Eureka 1e1bl1 and Phaeosphaeriasp. 1e4cs-1 and Their Cytotoxic Activities(Elsevier Ltd., 2021) Karakoyun, Çiğdem; Küçüksolak, Melis; Bilgi, Eyüp; Doğan, Gamze; Çömlekçi, Yiğit Ege; Bedir, ErdalBiotransformation of oleandrin (1) and nerigoside (2) by endophytic fungi; Alternaria eureka 1E1BL1 and Phaeospheria sp. 1E4CS-1, has led to the isolation of five new metabolites (3, 5, 6, 7 and 8) together with a known compound (4). The structures of the biotransformation products were elucidated by 1D-, 2D NMR and HR-MS. Phaeospheria sp. mainly provided monooxygenation reactions on the A and B rings, whereas A. eureka afforded both monooxygenated and desacetylated derivatives of the substrates. Cytotoxic activity of the compounds was tested against a non-cancerous (HEK-293) and four cancer (PANC-1, MIA PaCa-2, DU 145 and A549) cell lines by MTT cell viability assay. All compounds were less cytotoxic than oleandrin, which had IC50 values ranging between 2.7 and 41.9 nM. Two of the monohydroxylated metabolites, viz. 7(?)-hydroxy oleandrin (3) and 1(?)-hydroxy oleandrin (7), were also potent with IC50 values from 18.45 to 39.0 nM, while desacetylated + monohydroxylated, or dihydroxylated products had much lower cytotoxicity. Additionally, the lesser activity of 2 and its metabolite (6) possessing diginose as sugar residue inferred that oleandrose moiety is important for the toxicity of oleandrin as well as hydrophobicity of the steroid core. © 2020 Phytochemical Society of EuropeArticle Citation - WoS: 23Citation - Scopus: 22Microbial Transformation of Cycloastragenol and Astragenol by Endophytic Fungi Isolated From Astragalus Species(American Chemical Society, 2019) Ekiz, Güner; Yılmaz, Sinem; Yusufoğlu, Hasan; Ballar Kırmızıbayrak, Petek; Bedir, ErdalBiotransformation of Astragalus sapogenins (cycloastragenol (1) and astragenol (2)) by Astragalus species originated endophytic fungi resulted in the production of five new metabolites (3, 7, 10, 12, 14) together with 10 known compounds. The structures of the new compounds were established by NMR spectroscopic and HRMS analysis. Oxygenation, oxidation, epoxidation, dehydrogenation, and ring cleavage reactions were observed on the cycloartane (9,19-cyclolanostane) nucleus. The ability of the compounds to increase telomerase activity in neonatal cells was also evaluated. After prescreening studies to define potent telomerase activators, four compounds were selected for subsequent bioassays. These were performed using very low doses ranging from 0.1 to 30 nM compared to the control cells treated with DMSO. The positive control cycloastragenol and 8 were found to be the most active compounds, with 5.2- (2 nM) and 5.1- (0.5 nM) fold activations versus DMSO, respectively. At the lowest dose of 0.1 nM, compounds 4 and 13 provided 3.5- and 3.8-fold activations, respectively, while cycloastragenol showed a limited activation (1.5-fold).