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    Antimicrobial and antioxidant activity of phenolic extracts from walnut (Juglans regia L.) green husk by using pressure-driven membrane process
    (Springer India, 2023) Arslan, Hudaverdi; Koc, Eda Ondul; Ozay, Yasin; Canli, Oltan; Ozdemir, Sadin; Tollu, Gulsah; Dizge, Nadir
    In this study, antioxidant (DPPH and metal chelating), DNA cleavage, biofilm, and antimicrobial properties of extracted phenol from the walnut green husk (WGH) and its different concentrate and permeate samples were evaluated. For maximum phenolic compound extraction from the WGH first, the effects of solvent type (deionized water, methanol, n-hexane, acetone, and ethanol), solvent temperature (25-75 degrees C), and extraction time (0.5-24 h) were optimized. Then to concentrate phenolic compounds a pressure-driven membrane process was used with four different membrane types. The phenol contents of the concentrate samples were found to be microfiltration (MF) concentrate 4400 mg/L, ultrafiltration (UF) concentrate 4175 mg/L, nanofiltration (NF) concentrate 8155 mg/L, and reverse osmosis (RO) concentrate 8100 mg/L. LC-MSMS was used to determine the quantification of phenolic compounds in permeate and concentrate streams. In addition, all of the concentrate samples with high phenol content showed a high antioxidant activity as 100% with MF concentrate, UF concentrate, NF concentrated and RO concentrated. Likewise, concentrate samples were found to have very high antibiofilm activity as 82.86% for NF concentrate againts S. aureus, 85.80% for NF concentrate against P. aureginosa, 80.95% for RO concentrate against S. aureus, and 83.61% for RO-concentrate against P. aureginosa. When the antimicrobial activity of the extracted phenol from WGH and its different concentrate and permeate samples were evaluated by micro dilution and disk diffusion methods, it was found that the ability of the concentrate samples to inhibit bacterial growth was much higher than permeate ones. In addition, extracted phenol from WGH and its different concentrate and permeate samples showed significant DNA nuclease activity.
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    Nanocellulose synthesis from Tamarix aphylla and preparation of hybrid nanocellulose composites membranes with investigation of antioxidant and antibacterial effects
    (Elsevier, 2022) M'barek, Islem; Isik, Zelal; Ozay, Yasin; Ozdemir, Sadin; Tollu, Gulsah; Moussaoui, Younes; Dizge, Nadir
    Nanotechnology takes place in almost every stage of our lives and it has also started to find application in membrane technologies. In order to overcome the fouling phenomenon, which is the main problem of membrane processes, composite membranes containing metallic nanoparticles (NPs) with antibacterial properties are produced. Therefore, research continues to find environmentally friendly, inexpensive, and abundant materials to prevent membrane fouling. This study focused on the valorization of vegetable biomass Tamarix aphylla for nanocellulose (NC) synthesis which was coated subsequently with silver (NC-Ag NPs) and iron (NC-Fe NPs) nanoparticles to acquire the hybrid composites for ultrafiltration membrane preparation. The coated NC with metal NPs and synthesized membranes were characterized by SEM, EDX, FTIR, and XRD. The antioxidant and antimicrobial activities of NC and its coated forms with NPs were evaluated. It was found that significant scavenging abilities against the DPPH radical reached the maximum of 82.94% at 200 mg/L. The abilities of the three samples (NC, NC-Ag NPs, NC-Fe NPs) for DNA cleavage were tested and important outcomes were recorded. Furthermore, the antimicrobial abilities of the composites were examined by the microdilution procedure and they exhibited good ability. The biofilm inhibition rates of the composites were determined, where the highest biofilm inhibition against S. aureus and P. aeruginosa was recorded for NC-Ag NPs as 63.85% and 81.20%, respectively. Briefly, among the tested NC and NPs coated NC, NC-Fe NPs exhibited significant antimicrobial potential compared to the others. Thus, it may be promising hybrid nanocellulose complexes for antifouling membrane preparation.
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    Öğe
    Toxicity, Antibacterial, Antioxidant, Antidiabetic, and DNA Cleavage Effects of Dextran-Graft-Polyacrylamide/Zinc Oxide Nanosystems
    (Springer, 2024) Yalcin, M. Serkan; Ozdemir, Sadin; Prokopiuk, Volodymyr; Virych, Pavlo; Onishchenko, Anatolii; Tollu, Gulsah; Pavlenko, Vadim
    Synthesis of metal oxide nanoparticles-polymer nanocomposites is an emerging strategy in nanotechnology to improve targeted delivery and reduce the toxicity of nanoparticles. In this study, we report biological effects of previously described hybrid nanocomposites containing dextran-graft-polyacrylamide/zinc oxide nanoparticles (D-PAA/ZnO NPs) prepared from zinc sulfate (D-PAA/ZnONPs(SO42-)) and zinc acetate (D-PAA/ZnONPs(-OAc)) focusing primarily on their antimicrobial activity. D-PAA/ZnONPs(SO42-) and D-PAA/ZnONPs(-OAc) nanosystems were tested in a complex way to assess their antioxidant activity (DPPH assay), antidiabetic potential (alpha-amylase inhibition), DNA cleavage activity, antimicrobial, and antibiofilm activity. In addition, the toxicity of D-PAA/ZnONPs(SO42-) and D-PAA/ZnONPs(-OAc) nanosystems against primary murine splenocytes was tested using MTT assay. The studied nanosystems inhibited E.coli growth. For all the investigated strains, minimum inhibitory concentrations (MICs) of D-PAA/ZnONPs(SO42-) and D-PAA/ZnONPs(-OAc) were in the range of 8 mg/L-128 mg/L and 16 mg/L-128 mg/L, respectively. The nanocomposites demonstrated effective antibiofilm properties as 94.27% and 86.43%. The compounds showed good antioxidant, anti-alpha-amylase, and DNA cleavage activities. D-PAA/ZnONPs(SO42-) and D-PAA/ZnONPs(-OAc) nanosystems reduced cell viability and promoted cell death of primary murine spleen cells at concentrations higher than those that proved to be antibacterial indicating the presence of therapeutic window. D-PAA/ZnONPs(SO42-) and D-PAA/ZnONPs(-OAc) nanosystems show antioxidant, antidiabetic, DNA cleavage, antimicrobial, and antibiofilm activity against the background of good biocompatibility suggesting the presence of therapeutic potential, which should be further investigated in vivo.