Bioengineering / Biyomühendislik

Permanent URI for this collectionhttps://hdl.handle.net/11147/4529

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Potent Telomerase Activators From a Novel Sapogenin Via Biotransformation Utilizing Camarosporium Laburnicola, an Endophytic Fungus
    (BioMed Central Ltd., 2023) Küçüksolak, Melis; Yılmaz, Sinem; Ballar Kırmızıbayrak, Petek; Bedir, Erdal
    BACKGROUND: Cycloartane-type triterpenoids possess important biological activities, including immunostimulant, wound healing, and telomerase activation. Biotransformation is one of the derivatization strategies of natural products to improve their bioactivities. Endophytic fungi have attracted attention in biotransformation studies because of their ability to perform modifications in complex structures with a high degree of stereospecificity. RESULTS: This study focuses on biotransformation studies on cyclocephagenol (1), a novel cycloartane-type sapogenin from Astragalus species, and its 12-hydroxy derivatives (2 and 3) to obtain new telomerase activators. Since the hTERT protein levels of cyclocephagenol (1) and its 12-hydroxy derivatives (2 and 3) on HEKn cells were found to be notable, biotransformation studies were carried out on cyclocephagenol and its 12-hydroxy derivatives using Camarosporium laburnicola, an endophytic fungus isolated from Astragalus angustifolius. Later, immunoblotting and PCR-based ELISA assay were used to screen starting compounds and biotransformation products for their effects on hTERT protein levels and telomerase activation. All compounds showed improved telomerase activation compared to the control group. CONCLUSIONS: As a result of biotransformation studies, seven new metabolites were obtained and characterized, verifying the potential of C. laburnicola as a biocatalyst. Additionally, the bioactivity results showed that this endophytic biocatalyst is unique in transforming the metabolites of its host to afford potent telomerase activators. © 2023. The Author(s).
  • Article
    Citation - WoS: 14
    Citation - Scopus: 15
    Biotransformation of Ruscogenins by Cunninghamella Blakesleeana Nrrl 1369 and Neoruscogenin by Endophytic Fungus Neosartorya Hiratsukae
    (Elsevier Ltd., 2018) Özçınar, Özge; Tağ, Özgür; Yusufoğlu, Hasan; Kıvçak, Bijen; Bedir, Erdal
    Biotransformation of steroidal ruscogenins (neoruscogenin and ruscogenin) was carried out with Cunninghamella blakesleeana NRRL 1369 and endophytic fungus Neosartorya hiratsukae yielding mainly P450 monooxygenase products together with a glycosylated compound. Fermentation of ruscogenins (75:25, neoruscogenin-ruscogenin mixture) with C. blakesleeana yielded 8 previously undescribed hydroxylated compounds. Furthermore, microbial transformation of neoruscogenin by endophytic fungus N. hiratsukae afforded three previously undescribed neoruscogenin derivatives. While hydroxylation at C-7, C-12, C-14, C-21 with further oxidation at C-1 and C-7 were observed with C. blakesleeana, N. hiratsukae biotransformation provided C-7 and C-12 hydroxylated compounds along with C-12 oxidized and C-1(O) glycosylated derivatives. The structures of the metabolites were elucidated by 1-D (1H, 13C and DEPT135) and 2-D NMR (COSY, HMBC, HMQC, NOESY, ROESY) as well as HR-MS analyses.
  • Article
    Citation - WoS: 27
    Citation - Scopus: 30
    Biotransformation of Cyclocanthogenol by the Endophytic Fungus Alternaria Eureka 1e1bl1
    (Elsevier Ltd., 2018) Ekiz, Güner; Duman, Seda; Bedir, Erdal
    The microbial transformation of cyclocanthogenol (CCG), Astragalus sp. originated sapogenin, by the endophytic fungus Alternaria eureka 1E1BL1 isolated from Astragalus angustifolius was investigated. Hydroxylation, oxidation, epoxidation, O-methylation, ring-expansion and methyl migration reactions were observed on the triterpenoid skeleton. As a result, eight metabolites were isolated and the structures of the previously undescribed compounds were established by 1-D, 2-D NMR and HR-MS analyses.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 24
    Biotransformation of Neoruscogenin by the Endophytic Fungus Alternaria Eureka
    (American Chemical Society, 2018) Özçınar, Özge; Tağ, Özgür; Yusufoğlu, Hasan; Kıvçak, Bijen; Bedir, Erdal
    Biotransformation of neoruscogenin (NR, 1, spirosta-5,25(27)-diene-1β,3β-diol), the major bioactive sapogenin of Ruscus preparations, was carried out with the endophytic fungus Alternaria eureka. Fourteen new biotransformation products (2-15) were isolated, and their structures were elucidated by NMR and HRESIMS data analyses. A. eureka affected mainly oxygenation, oxidation, and epoxidation reactions on the B and C rings of the sapogenin to afford compounds 8-15. In addition to these, cleavage of the spiroketal system as in compounds 2-7 and subsequent transformations provided unusual metabolites. This is the first study reporting conversion of the spirostanol skeleton to cholestane-type metabolites 2-5. Additionally, the cleavage of the C-22/C-26 oxygen bridge yielding a furostanol-type steroidal framework and subsequent formation of the epoxy bridge between C-18 and C-22 in 7 was encountered for the first time in steroid chemistry.