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    Antioxidant, antimicrobial activities and total flavonoid contents of Cirsium bulgaricum DC. leaf extracts
    (Marmara Univ, Fac Pharmacy, 2015) Karasakal, Ayça; Demirci, Ahmet Şükrü; Demirok, Nazan Tokatlı; Cabi, Evren
    In this study, the antioxidant activities of methanol and acetone extracts of Cirsium bulgaricum DC. (Asteraceae) were evaluated by five antioxidant assays, including phosphomolybdate method, cupric ion reducing capacity (CUPRAC), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonicacid)/persulfate) ABTS/Persulfate, N,N-dimethyl-pphenylenediamine (DMPD) and a Ce(IV)-based reducing capacity (CERAC) methods. The 80% methanol and acetone extracts showed 0.005-6.16 +/- 0.03 mmol/g and 0.004-5.02 +/- 0.02 [(trolox (TR), catechin (CT), epicatechin (EC), rutin (RT), quercetin (QR), naringin (NG) in CUPRAC and ABTS/Persulfate methods, respectively]. According to DMPD methods, inhibition effect were showed 2.3%+/- 0.02 for 80% methanol and 4.6%+/- 0.07 for acetone. Ascorbic acid equivalent mmol (AA)/g extract in CERAC method was found to be 0.0834 +/- 0.09 for 80% methanol and 0.5622 +/- 0.05 for acetone. Ascorbic acid equivalent mu g ascorbic acid (AA) / mL extract were found 807.6 +/- 0.07 for 80% methanol and 292.4 +/- 0.01 for acetone in phpsphomolybdate method. In the addition to the antioxidant activity of the extract, the total flavonoid content was measured. Total flavonoid content of 80% methanol and acetone extracts was found to be 105.5-645 +/- 0.04 mu g/ml quercetin and rutin equivalent. For the determination of antibacterial activities Escherichia coli (E. coli) ATCC 25922, Escherichia coli(E. coli) O157:H7 ATCC 33150, Salmonella Enteritidis(S. Enteritidis) ATCC 1 3 0 7 6, Listeria monocytogenes(L. monocytogenes) ATCC 7 6 4 4, Staphylococcus aureus(S. aureus) ATCC 25923 bacteria were used as test bacteria. Acetone extracts showed antibacterial activity against all of the tested bacteria ranged between 17.00 +/- 1.72-19.88 +/- 1.75 mm and 80% methanol extracts showed antibacterial activity against all of the tested bacteria ranged between 11.35 +/- 1.43-14.43 +/- 1.32 mm.
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    BEBEKLERDEN İZOLE EDİLEN Lactobacillus spp.’nin FONKSİYONEL ÖZELLİKLERİNİN BELİRLENMESİ
    (Namık Kemal Üniversitesi, 2014) Demirok, Nazan Tokatlı
    Yaşamın ilk yılında bağırsak sisteminin dengeli kolonizasyonu bağışıklığın bebeklik döneminde kazanılması yönüyle önem arzetmektedir. Laktobasiller, konakçıları için yararlı ve günümüzde potansiyel probiyotik bakteriler olarak değerlendirilmektedir. Çalışmamızda, bir yaşından küçük bebek feçeslerinden fenotipik özellikler baz alınarak izole edilen laktobasiller; 16S rDNA dizi analizi sonucunda; L.paracasei subsp. paracasei, (41), L.fermentum (24), L.rhamnosus (11), L.casei (17), Lactobacillus sp. (11) olarak tanımlanmıştır. Tanımlanan laktobasil izolatlarının probiyotik ve teknolojik özelliklerini belirlemek amacıyla, antibakteriyel aktiviteleri, asit, hidrojen sülfür, hidrojen peroksit, D- ve L-laktat üretme yetenekleri, asit ve safra tuzu toleransları, bazı antibiyotiklere hassasiyetleri ve tutunma yetenekleri gibi özellikleri incelenmiştir. İzolatların tamamında 24 saatlik inkübasyon sonrasında pH 5’in altına düşmüştür. İzolatlar hidrojen sülfür üretme yetenekleri dikkate alındığında; L.casei’nin tümünün, L.paracasei subsp. paracasei ve L.rhamnosus’un hemen hemen hepsinin L.fermentum’un ise bir kısmının pozitif sonuç verdiği belirlenmiştir. İzole edilen diğer türlere göre L.rhamnosus’un safra tuzuna daha duyarlı olduğu, düşük pH’ya (pH 3) ise L.casei ’nin diğer türlere göre daha dirençli olduğu tespit edimiştir. Türler arasındabelirgin fark olmamakla birlikte xylen ile yapılan hidrofobisite tespitinde L.rhamnosus’un daha hidrofobik olduğu belirlenmiştir. İzolatların tamamının chloramphenicol, penicillin ve tetracycline duyarlı, çoğunun kanamycin ve streptomycine dirençli olduğu belirlenmiştir. İzole edilen lactobacillus spp.’lerin çoğunun L (+) laktik asit, L.fermentum izolatlarının ise DL laktik asit ürettiği belirlenmiştir. İzolatların tümü genellikle analiz edilen patojen bakterilere inhibisyon etkide bulunmakla birlikte, en yüksek zon çapı S.aeureus'a karşı verilmiştir. İzolatların bir kısmının hidrojen peroksit ürettiği belirlenirken, en yüksek miktarda hidrojen peroksiti L.rhamnosus'un ürettiği tespit edilmiştir.
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    Combined Effect of Ultrasound and Microwave Power in Tangerine Juice Processing: Bioactive Compounds, Amino Acids, Minerals, and Pathogens
    (Mdpi, 2022) Demirok, Nazan Tokatlı; Yıkmış, Seydi
    The inhibition of Escherichia coli ATCC 25922 (E. coli), Staphylococcus aureus ATCC6538 (S. aureus), Salmonella Enteritidis ATCC 13076 (S. Enteritidis), and Listeria monocytogenes DSM12464 (L. monocytogenes) is one of the main aims of the food industry. This study was the first in which the use of ultrasound and microwave power were applied to optimize the values of the bioactive components, amino acids, and mineral compositions of tangerine juice and to inhibit Escherichia coli, Staphylococcus aureus, Salmonella Enteritidis, and Listeria monocytogenes. The response surface methodology (RSM) was used to describe the inactivation kinetics, and the effects of ultrasound treatment time (X-1: 12-20 min), ultrasound amplitude (X-2:60-100%), microwave treatment time (X-3: 30-40 s), and microwave power (X-4:200-700 W). The optimum parameters applied to a 5-log reduction in E. coli were determined as ultrasound (12 min, 60%) and microwave (34 s, 700 W). The optimum condition ultrasound-microwave treatment was highly effective in tangerine juice, achieving up to 5.27, 5.12, and 7.19 log reductions for S. aureus, S. Enteritidis, and L. monocytogenes, respectively. Ultrasound-microwave treatment increased the total phenolic compounds and total amino acids. While Cu, K, Mg, and Na contents were increased, Fe and Ca contents were lower in the UM-TJ (ultrasound-microwave-treated tangerine juice) sample. In this case, significant differences were detected in the color values of ultrasound-microwave-treated tangerine juice (UM-TJ) (p < 0.05). The results of this study showed that ultrasound-microwave treatment is a potential alternative processing and preservation technique for tangerine juice, resulting in no significant quality depreciation.
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    Effects of Non-Thermal Treatment on Gilaburu Vinegar (Viburnum opulus L.): Polyphenols, Amino Acid, Antimicrobial, and Anticancer Properties
    (MDPI, 2022) Erdal, Berna; Yıkmış, Seydi; Demirok, Nazan Tokatlı; Bozgeyik, Esra; Levent, Okan
    Simple Summary In this study, traditionally produced vinegar made from gilaburu (C-GV) and thermally pasteurized gilaburu vinegar (P-GV), and (ultrasound-treated gilaburu vinegar (UT-GV) were evaluated. At the same time, ultrasound treatment enriched 11 phenolic compounds (gallic acid, protocatechuic acid, hydroxybenzoic acid, vanillic acid, p-coumaric acid, rutin, ferulic acid, o-coumaric acid, neohesperidin, quercetin, trans-cinnamic). Ultrasound showed different effects on free amino acids and volatile profiles. In general, ultrasound showed more positive results than thermal pasteurization. Six important minerals (Ca, Fe, K, Mg, Mn, and Zn) were detected in gilaburu vinegar, and ultrasound treatment increased the Fe content. Gilaburu vinegar, prepared by different methods, had potential antibacterial and anti-cancer activity. Gilaburu (Viburnum opulus L.) is an important fruit that has been studied in recent years due to its phytochemicals and health benefits. In this study, traditionally produced vinegar made from gilaburu fruit (C-GV) was evaluated. Vinegar with higher levels of bioactive components optimized by response surface methodology (RSM) was also produced using ultrasound (UT-GV). The maximum optimization result for the bioactive components was achieved at 14 min and 61.2 amplitude. The effectiveness of thermal pasteurization (P-GV) on gilaburu vinegar was evaluated. An increase was detected for every organic acid with ultrasound treatment. In the UT-GV and C-GV samples, arabinose was present, which is useful for stimulating the immune system. Gilaburu vinegar samples contained 29-31 volatile compounds. The smallest amount of volatile compounds was found in P-GV (1280.9 mu g/kg), and the largest amounts of volatile compounds were found in C-GV (1566.9 mu g/kg) and UT-GV (1244.10 mu g/kg). In the UT-GV sample, Fe was increased, but Ca, K, Mg, and Mn were decreased. A total of 15 polyphenols were detected in C-GV, P-GV, and UT-GV samples, and gallic acid was the most common. A total of 17 free amino acids were detected in gilaburu vinegar samples. Ultrasound provided enrichment in total phenolic compounds and total free amino acids. All three vinegar samples had good antimicrobial activity against pathogens. The efficacy of C-GV, P-GV, and UT-GV samples against colon and stomach cancer was determined, but there were no significant differences between them. As a result, ultrasound treatment is notable due to its antimicrobial and anticancer activity, especially for the enrichment of phenolic compounds and amino acids in gilaburu vinegar.
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    Investigation of antimicrobial and antioxidant activities of essential oils extracted from medicinal plants
    (M H Schaper Gmbh Co Kg, 2016) Gümüş, Tuncay; Demirci, Ahmet Şükrü; Sonuc, Munteha Nur; Demirok, Nazan Tokatlı; Tulukcu, Eray; Gülcü, Mehmet
    Essential oils of eleven plants including anise, hyssop, flos lavandulae, pot marigold, fennel, mint, chamomile petal, clary sage, cilantro, herba lippiae and dill were screened for total phenolic content by the Folin-Ciocalteu method, for potential antioxidant activity using the phosphomolybdenum assay and for antiradical activity by the 1,1-diphenyl-2-picryl hydrazyl (DPHH) method. The antimicrobial activity was examined by using agar disc diffusion as well as the minimum inhibitory concentration (MIC) method. The essential oils showed considerable antimicrobial activity against most of the tested microorganisms. The essential oil of dill was very effective in inhibiting the growth of all bacterial strains tested, with a low MIC (125 mu l/ml). Overall, the lowest MIC was found for E. coli O157:H7 and E. coli ATCC 25922 while the highest values were found for S. aureus and L. monocytogenes. The highest total antioxidant capacity as ascorbic acid equivalent (AAE) of 195.27 mg/g was obtained for mint with the phosphomolybdenium assay. The highest percentage of inhibition of DPPH radical was obtained with essential oil from dill (92.70 %). It was followed by radical scavenging activities of essential oils from mint (81.00 %) and anise (71.53 %). Total phenolic content of the essential oils ranged from 2.33 to 695.06 mg gallic acid per 100 g of the samples. Mint and dill had the highest content of total phenols. The essential oils of mint, dill, anise hyssop, and flos lavandulae may prove to be a good source of antioxidant and antimicrobial agents for the food and pharmaceutical industries.
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    Öğrencilerin Antropometrik Ölçümleri ile Akdeniz Diyeti ve Beslenme Alışkanlıkları Arasındaki İlişkinin Değerlendirilmesi
    (İstanbul Gelişim Üniversitesi, 2022) Torpil, Hilal; Demirok, Nazan Tokatlı
    Amaç: Çalışmada, Tekirdağ Namık Kemal Üniversitesi Beslenme ve Diyetetik bölümünde öğrenim gören öğrencilerin Akdeniz Diyet Kalite İndeksi ve sağlıklı yaşam biçimleriyle ilgili akademik bilgilerini kendi yaşamlarına uygulayabilme yetenekleri ve sağlıklı beslenme takıntısının saptanarak Akdeniz Diyet Kalite İndeksi ile antropometrik ölçümler arasındaki olası ilişkinin değerlendirilmesi amaçlanmıştır.Yöntem: Çalışmanın örneklemini çalışmaya katılım kriterlerini karşılayan 18-24 yaş arasında gönüllü olan dördüncü sınıflarda öğrenim gören 54, üçüncü sınıflarda öğrenim gören 65 ve ikinci sınıflarda öğrenim gören 59 öğrenci olmak üzere toplamda 174 öğrenci oluşturmuştur. Araştırmaya katılan öğrencilere yüz yüze görüşme yöntemiyle anket formu uygulanmıştır. Ayrıca anket formu uygulanan öğrencilerin antropometrik ölçümleri ve vücut kompozisyonu saptanmıştır.Bulgular: Öğrencilerin Akdeniz diyet kalite indeksi ortalamasının; 5,3±2,95; ORTO-11 ölçeği puan ortalamalarının ise 24,75±6,48 olduğu bulunmuştur. Öğrencilerin ortalama vücut ağırlığı 59,7±11,1 kg ve beden kitle indeksi (BKİ) ortalamaları ise 21,72±3,1 olarak saptanmıştır. Araştırmamızda öğrenim görülen sınıf düzeyi arttıkça Akdeniz diyetine uyumun arttığı belirlenmiştir. Öğrencilerin Akdeniz diyet kalite indeksi puanları arttıkça BKİ değerlerinin ve ORTO-11 ölçeği puanlarının azaldığı tespit edilmiştir (p<0,05).Sonuç: Akdeniz diyetine uyumun; bireylerin vücut ağırlığı, BKİ ve vücut kompozisyonunu olumlu yönde etkilediği belirlenmiştir. Ayrıca ortorektik davranışlar ile Akdeniz diyetine uyum arasında pozitif bir ilişki saptanmıştır.
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    Probiotic and functional characterization of lactobacillus spp. isolated from infant faeces
    (Elsevier Science Bv, 2017) Demirok, Nazan Tokatlı; Durak, M. Zeki; Arıcı, Muhammet
    [No Abstract Available]
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    Protective effects of Acetobacter ghanensis against gliadin toxicity in intestinal epithelial cells with immunoregulatory and gluten-digestive properties
    (Springer Heidelberg, 2022) Doğuer, Çaglar; Akalan, Hande; Demirok, Nazan Tokatlı; Erdal, Berna; Mete, Rafet; Bilgen, Türker
    Purpose The aim of this study was to establish whether Acetobacter ghanensis, the probiotic characteristics of which were evaluated previously, attenuates gliadin-induced toxicity in intestinal epithelial cells with gluten-digestive and immunoregulatory properties. Methods A co-culture model of human intestinal epithelial cell (Caco-2) monolayers on top of peripheral blood mononuclear cells (PBMCs) obtained from patients with celiac disease (CD) was established. The gluten-digestive properties of A. ghanensis were determined by checking bacterial growth in a medium containing gluten as the main nitrogen source. The mRNA levels of genes encoding TJ-associated proteins were measured by quantitative real-time PCR (qRT-PCR). The concentrations of IL-6 and TNFac were determined by enzyme-linked immunosorbent assay (ELISA). Results We found that PT-gliadin disrupted intestinal barrier integrity by modulating the expression of TJ-associated genes encoding zonulin (increased by similar to 60%), zonula occludens-1 (ZO-1) (decreased by similar to 22%), and occludin (decreased by similar to 28%) in Caco-2 cells. Furthermore, PT-gliadin treatment in Caco-2 cells was associated with increased concentrations of IL-6 (similar to 1.6-fold) and TNFac (similar to twofold) from PBMCs. These modulatory effects of PT-gliadin, however, were suppressed when Caco-2 cells were subjected to A. ghanensis in the presence of PT-gliadin. As a factor underlying these protective effects, we showed that A. ghanensis could digest gluten peptides. Conclusions To our knowledge, the current study is the first to demonstrate that A. ghanensis improves intestinal barrier functions by attenuating the modulatory effects of PT-gliadin with immunoregulatory and gluten-digestive properties.