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  • MakaleYalnız künye2026
    Effects of sunlight ripening process on the biological activities of persimmon (Diospyros kaki L.) peel and pulp extracts

    Kardil, Uğur; Akar, Zeynep; Düzgün, Azer Özad

    The aim of the study was to evaluate the biological properties of the peel and pulp extracts of persimmons, with consideration of the impact of different ripening conditions (B: on-branch ripened and S: sunlight ripened). The data demonstrated that the sunlight ripened persimmon peel (S. peel) extract exhibited a higher total phenolic and flavonoid content, with 157 and 7.3 µg/mL GAE respectively. The S. peel extract exhibited the highest antioxidant activity, exhibiting 1.1578 mg/mL IC50, 54.095 and 0.0262 µM Trolox equivalent (TE)/g fresh weight (FW), as determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging assay, ferric reducing antioxidant power (FRAP) and cupric reducing antioxidant capacity (CUPRAC) respectively. LC-MS/MS analysis revealed that the peel and pulp phenolic composition of persimmon ripening process different conditions changed. The activity of protocatechuic, chlorogenic, caffeic and ferulic acids identified in persimmon extracts was determined by HPLC-DAD-FRAP assay. ICP-OES analysis revealed that potassium exhibited the highest mineral content of persimmon, with values ranging from 575.680 to 2031.360 mg/kg. The S. peel extract was more inhibitory activity against bovine carbonic anhydrase (BCA) and α-glucosidase then other extracts. Moreover, the S. peel extract was found to demonstrate the highest level of antibiofilm activity, reducing the strong biofilm formation capacity of the A. baumannii isolate to negative, both qualitatively and quantitatively. The study suggests that the ripening of persimmon fruit in sunlight may increase biological activity and may be useful in the prevention and treatment of diseases associated with oxidative damage, diabetes and bacterial infections.

    • SDG 2 · Açlığa Son
  • MakaleAçık Erişim2026
    Green Synthesis and Bioactivities of Silver Nanoparticles Derived from Mercurialis annua L. Extract

    Salad, Aisha Mohamud; Akar, Zeynep

    Biogenic synthesis using plant materials provides a sustainable alternative to classical nanoparticle fabrication, minimizing chemical hazards and decreasing energy input. In this study, silver nanoparticles (AgNPs) were prepared using an aqueous extract of Mercurialis annua and characterized. Physicochemical properties of the AgNPs were confirmed using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), and transmission electron microscopy coupled with energy-dispersive X-ray (TEM–EDX), which collectively indicated crystalline, spherical silver nanoparticles stabilized by extract-derived functional groups. Subsequently, the biological activities of both the nanoparticles and the extract were comparatively evaluated using antioxidant tests, including cupric ion reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), total phenolic content (TPC), and total flavonoid content (TFC), as well as enzyme inhibition tests targeting α-glucosidase and carbonic anhydrase. Liquid chromatography-mass spectrometry profiling identified 31 phenolic constituents in the extract, with ferulic, caffeic, salicylic, and 4-hydroxybenzoic acids detected in high abundance. Overall, the biosynthesized AgNPs demonstrated higher antioxidant performance and stronger inhibitory effects on both enzymes compared with the crude extract. These results indicate that M. annua-based AgNPs hold considerable promise sustainable and effective bioactive agents for future biomedical and biotechnological applications.

    • SDG 12 · Sorumlu Üretim ve Tüketim
  • MakaleAçık Erişim2025
    Assessment of antioxidant, antimicrobial, antibiofilm, carbonic anhydrase and α-glucosidase inhibitory activities of Alchemilla vulgaris L. extracts

    Düzgün, Azer Özad; Akar, Zeynep; Kardil, Ugur

    This study was to investigate the biological properties (antioxidant, enzyme inhibitory and antimicrobial activity) of water extract (WE), 50:50% water:ethanol extract (WEE) and ethanol extract (EE) of aerial parts of Alchemilla vulgaris L. which was traditionally used to alleviate and treat many diseases. The WEE extract exhibited the highest total phenolic content (TPC), with a value of 612 µg/mL GAE, while the EE extract demonstrated the highest total flavonoid content (TFC), with a value of 0.086 µg/mL GAE. Also, the data demonstrated that the WEE extract exhibited the highest radical scavenging capacities and antioxidant activities, exhibiting 0.0056, 0.0028 mg/mL SC50 and 267, 0.081 μM TEAC, as determined by the DPPH, ABTS, FRAP and CUPRAC assays, respectively. The WEE extract was found to be an effective bovine carbonic anhydrase (BCA) and α-glucosidase inhibitor with an IC50 values of 0.0628 and 0.0535 mg/mL, respectively. The EE extract showed activity against both Gram-negative and Gram-positive bacteria used in the study. EE extract has the highest activity against Yersinia pseudotuberculosis and the lowest activity against Streptococcus pyogenes. Furthermore, the extracts significantly reduced the biofilm ability of Acinetobacter baumannii isolate, which has strong biofilm ability. EE and WE reduced the biofilm formation capacity of the strain to a weak level, while WEE extract reduced it to a moderate level. The results suggest that EE has a significant effect in combating antibiotic resistance, while WEE has high antioxidant activity and good inhibitory effect against BCA and α-glycosidase enzymes. In addition, the results revealed that solvent extracts with different solvent composition and polarity may have different effects on diverse bioactivity tests.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2024
    Investigation of antibiofilm and biological activities of Vaccinium arctostaphylos L.

    Düzgün, Azer Özad; Akar, Zeynep; Kardil, Ugur

    This study investigated the total phenolic and flavonoid contents and the antioxidant, antimicrobial, antibiofilm and α-glucosidase inhibitory activities of methanol extract from Vaccinium arctostaphylos L. leaf and fruit parts. The highest antioxidant activity with 53 µM TEAC and 0.0084 mg/mL SC50 using the ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays, respectively determined in leaf part. The data indicated that the leaf of the plant had the higher total phenolic content (49 µg/mL GAE) and total flavonoid content (0.071 µg/mL QAE) compared to fruit. The α-glucosidase enzyme activity of the leaves (0.179 mg/mL IC₅₀) was observed to be higher than that of the fruits (0.386 mg/mL IC₅₀). The MIC values of the leaf and fruit parts of blueberry were 6.25 mg/ml and 3.125 mg/ml, respectively. The results of this study indicate that the leaf extract was found to significantly reduce the biofilm-forming capacity of the Acinetobacter baumannii isolate by approximately 3-fold, whereas the fruit extract was observed to have only a marginal effect, reducing the biofilm-forming capacity by approximately 1.4-fold. The effects of plant extracts on microbial biofilms may be examined with a view to combating antibiotic resistance. Also results suggesting that it might be an effective and safety medical plant to prevent or treat diseases associated with oxidative damage and bacterial infections. Consequently, further research on natural substances may lead to the development of treatment options.

  • MakaleAçık Erişim2024
    Vitis Labrusca L. Kabuk Ekstraktlarının Antibiyofilm, Antidiyabetik ve Antioksidan Potansiyelleri

    Düzgün, Azer Özad; Akar, Zeynep; Kardil, Ugur

    Bu çalışmada, Vitis labrusca L. bitkisinin kabuk kısımlarından elde edilen metanol, 50:50% metanol:su ve su ekstraktlarının antioksidan, antimikrobiyal, antibiyofilm ve α-glukozidaz inhibitör aktiviteleri ile toplam fenolik ve flavonoid içerikleri incelenmiştir. 50:50% metanol:su özütü, sırasıyla FRAP ve DPPH• radikal süpürücü analizleriyle belirlendiği üzere, 153 μM TEAC ve 0,0947 mg/mL SC50 ile en yüksek antioksidan aktiviteyi sergilemiştir. 50:50% metanol:su ekstraktı, sırasıyla 141 μg/mL GAE ve 0,103 mg/mL IC₅₀ değeri ile diğer çözücü ekstraktları arasında en yüksek toplam fenolik içeriği ve α-glukozidaz enzim inhibisyonunu sergilemiştir. Metanol, su ve 50:50% metanol:su ekstraktlarının MİK değerleri, klinik antibiyotik direnci olan Acinetobacter baumanii' ye karşı sırasıyla 6.25, 25 ve 12.5 mg/mL olarak belirlenmiştir. Metanol, su ve %50:50 metanol:su ekstraktlarının Acinetobacter baumannii izolatının biyofilm oluşturma kapasitesini sırasıyla yaklaşık 1.7, 1.6 ve 1.3 kat azalttığı bulunmuştur. Bulgular, 50:50% metanol:su ekstraktının en yüksek fenolik içerik, antioksidan aktivite ve α-glukozidaz inhibisyonu sergilediğini, metanol ekstraktının ise en belirgin antimikrobiyal ve antibiyofilm aktivitelerini gösterdiğini ortaya koymuştur. Araştırmamızın sonuçları, çeşitli çözücülerin ve bunların ilgili bileşimlerinin kullanımının biyolojik aktivitede önemli farklılıklar yaratma kapasitesine sahip olduğunu göstermektedir. Bu durum, V. labrusca kabuk bileşenlerinin oksidatif stres ve bakteriyel enfeksiyonlarla ilgili rahatsızlıkların ele alınmasında değerli bir yol olarak hizmet etme potansiyeline işaret etmektedir.

  • MakaleAçık Erişim2024
    Effect of Different Storage Conditions and Infusion Times on Antioxidant and Antimicrobial Activites and Total Phenolic Content of Rosehip Fruits

    Düzgün, Azer Özad; Acet, Tuba; Baltaci, Cemalettin; Akmeşe, Osman; Ural, Mustafa Nuri; Akar, Zeynep; Darak, Münevver; Kılınç, Kagan

    Rosa canina L. (Rosehip) is a medicinal plant with strong antioxidant properties.The content of rosehip and accordingly its antioxidant capability may vary according to the way the fruits are used, storage, infusion, freezing and drying methods. In study, it was aimed to determine the antioxidant, antimicrobial activities in rosehip infusion products and extracts under these conditions. Fresh, frozen, dried and +40C stored fruits were infused at 90 degrees and infusion groups were formed. During infusion, samples were taken at 30, 60, 90, 120, 300 and 360th minutes and antioxidant activity (DPPH, FRAP and ABTS methods), total phenolic and total flavonoid contents (TPC and TFC), and antimicrobial activity were analyzed. In addition, phenolic compound content was investigated in 3 different extracts by HPLC method. Dried rosehip (DR) infusing samples were found to have the highest antioxidant activity, TPC and TFC compared to all groups (p-value ranged between 0.000 and 0.05).). Significant decreases were detected in the parameters according to storage and freezing times. A total of 8 phenolic compounds, the highest concentration of which was epicatechin, were detected in aqueous and ethanolic extracts of dried and stored at 40C rosehip (DR+40C) and dried rosehip (DR) fruits. For antimicrobial analysis, Total 7 different Gram (+) and (Gram (-) bacterial strains, were used. While antimicrobial activity was observed in the extracts, no activity was observed in the infusion products. It was determined that antioxidant activity increased during 360 minute infusion time, although it varied according to storage conditions.

    • SDG 2 · Açlığa Son
  • MakaleAçık Erişim2024
    Determination of the Cytotoxicity and Antibiofilm Potential Effect of Equisetum arvense Silver Nanoparticles

    Akar, Zeynep; Akay, Seref; Ejder, Nebahat; Özad Düzgün, Azer

    This study aimed to synthesize and characterize silver nanoparticles (AgNPs) by green synthesis from Equisetum arvense (Ea) extracts and to investigate their cytotoxicity, antibiofilm activity, and α-glucosidase enzyme inhibition. Diverse characterization techniques were applied to verify the production of nanoparticles. SEM examination confirmed that the size of nanoparticles is in the range of 40–60 nm. Also, interactions between silver and natural compounds of plant extract were confirmed through FT-IR and EDX analyses. It was determined that Equisetum arvense silver nanoparticles had antibiofilm activity against three different clinical strains with high biofilm-forming ability. AgNPs reduced the biofilm-forming capacity of clinical A. baumannii isolate with strong biofilm-forming capacity by approximately twofold, while the capacity of clinical K.pneumonaie and E.coli isolates decreased by 1.5 and 1.2 fold, respectively. The α-glucosidase enzyme inhibition potential of the AgNPs, which is determined as 93.50%, was higher than the plant extract with, and the α- 30.37%. MTT was performed to assess whether incubation of nanoparticles with A549 and ARPE-19 cell lines affected their viability, and a dramatic reduction in cell growth inhibition of both A549 and ARPE-19 cells was observed. It has been shown that A549 cells treated with 200 and 150 µg/mL nanoparticles had less cell proliferation compared to control cells at 24-h and 48-h incubation time. According to these results, Ea-derived AgNPs appear to have potential anticancer activity against A549 cancer cells. Investigating the effects of green synthesis nanoparticles on microbial biofilm and various tumors may be important for developing new therapies. The outcomes of this study have showed that Ea-AgNPsmay have a high potential both in the treatment of pathogenic strains that form biofilms, as well as in anticancer therapy use.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleYalnız künye2023
    Determination of cytotoxic, anti-acetylcholinesterase and antioxidant activity of some medicinal Artemisia spp.

    Gıdık, Betül; Kara, Yakup; Akar, Zeynep; Demir, Elif Ayazoglu; Can, Zehra

    The study aims to investigate the antioxidant activities, phenolic compounds, acetylcholinesterase enzyme inhibition and cytotoxic effects of two different Artemisia spp. (Artemisia dracunculus L. and Artemisia dracunculoides Pursh) cultivated in Türkiye organically, for the first time. The total phenolic and total flavonoid contents of the plants were determined spectrophotometrically while antioxidant activity DPPH•, CUPRAC, and FRAP was determined using the colorimetric method. And also, acetylcholinesterase in vitro enzyme inhibition activity and anti-cancer activity against human melanoma (VMM917, CRL-3232), lung carcinoma (A549, CCL-185), and normal human fibroblast (hGF, PCS-201-018) cells were studied. Total phenolic (225-324 μg GAE/mL extract) and total flavonoid contents (0.066-0.085 μg QE/mL extract), antioxidant activity Color Scavenging Concentration 50% (DPPH• (CSC50: 1.371-1.655 mg/mL), CUPRAC (0.246-0.344 μM CTEAC) and FRAP (462.133-726.661 μM CTEAC)). A. dracunculus and A. dracunculoides extracts inhibited 40.09 ± 0.65%, and 39.48 ± 3.68% of acetylcholinesterase activity. It was determined that demonstrated the selective effect of A. dracunculus and A. dracunculoides on the cytotoxicity of A549 and hGF cells. According to our results, both tarragon plant species, it may be said that it is not only consumed as food but also used for therapeutic purposes will be beneficial for health.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
  • MakaleAçık Erişim2023
    Green biosynthesis, characterization of silver nanoparticles using a green alga Spirogyra sp. and their antioxidant and enzyme activities

    Başoğlu, Aysel; Akar, Zeynep

    A simple, environmentally friendly, inexpensive, and one-step alternative method was reported for the green biosynthesis of silver nanoparticles (AgNPs) operating the Spirogyra sp. extract as a reducing and stabilizing substance. Concentration of AgNO3 and reaction time were optimized to prepare AgNPs under controlled conditions. The synthesized silver nanoparticles were characterized by UV-Vis absorption spectroscopy, fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and elemental mapping. The TEM analysis showed that the average particle size of AgNPs was 18.3 nm. Structural details of silver nanoparticles elucidated by Selected Area Electron Diffraction (SAED) based on TEM images. In addition, biological activity tests were applied to nanoparticles and algal extracts to determine antioxidant activity (3 different tests: DPPH (1,1-diphenyl-2-picrylhydrazil) radical scavenging activity, total phenolic content (TPC) and total flavonoid content (TFC)) and α-glucosidase enzyme inhibition. Antioxidant activity and α-glucosidase enzyme inhibition values of silver nanoparticles are higher than the values of Spirogyra sp. extracts.

  • MakaleAçık Erişim2023
    Chemical Composition of Pistacia terebinthus L. and its Phytochemical and Biological Properties

    Fidan, Muhammed Said; Baltaci, Cemalettin; Öz, Mehmet; Akar, Zeynep

    Vitamin C, enzyme activities, phenolic compounds, antioxidant capacity, antimicrobial activity, and essential oil analyses of ripe and unripe fruits of P. terebinthus were investigated. Vitamin C amounts of ripe and unripe fruits were 63.2 and 15.4 mg/100g, respectively. The main phenolic compounds of unripe and ripe fruits are rutin, syringic acid, and gallic acid. It was determined that the enzyme inhibitor activities in the ripe and unripe fruits were 0.136 mg/mL and 2.14 mg/mL. In all of the free radical scavenging (DPPH and ABTS) activity, ferric (III) ion reducing antioxidant power (FRAP) capacity, total phenolic substance amounts (TPC), total flavonoid substance amounts (TFC), and total antioxidant activity (TAC) antioxidant methods analyzed with plant parts, the methanol extracts obtained from the ripe fruits of the P. terebinthus showed higher antioxidant properties than the methanol extracts obtained from the unripe fruits. Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 showed antimicrobial activity against microorganisms, while methanol extracts obtained from unripe fruit samples did not show antimicrobial activity against the microorganisms used. The chemical grade with the most compounds in the essential oils of P. terebinthus were monoterpenoids, sesquiterpenes, and monoterpenes in unripe and ripe fruits, respectively. The main components were a-pinene with 22.8% and 27.3% ratios in unripe and ripe fruits, respectively.

    • SDG 2 · Açlığa Son
Tam Kayıt
AlanDeğerDil
dc.date.accessioned2026-10-22T09:26:27.498626625Z
dc.date.available2026-10-22T09:26:27.498626625Z
dc.identifier.urihttps://rdlopen.rawdatalibrary.net/r/gumushane/11115
dc.rightsinfo:eu-repo/semantics/openAccess
dc.titleAkar, Zeynep
dspace.entity.typePerson
person.affiliation.nameSağlık Bilimleri Fakültesi, İş Sağlığı ve Güvenliği Bölümü
person.familyNameAkar
person.givenNameZeynep
person.identifier.orcid0000-0001-9262-8070
person.identifier.scopus57190249359
person.identifier.wosOCL-3603-2025
person.identifier.yokDBC1FFFBC6313ED2
person.interestKimya
person.interestBiyokimya
person.jobTitleDoç. Dr.
person.statusverified
person.urlhttps://rdlsis.gumushane.edu.tr/tr/researcher/zeynep-akar