Browsing by Author "Doyuk, F"

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    Identification of Marker Molecules in Aqueous Plant Extracts Affecting the Gold Nanostructures' Morphology and Size
    Elgaleidh, MAM; Tepe, HD; Doyuk, F; Çeter, T; Yazgan, I
    This work was performed as a comparative study using nine different aqueous pollen grain extracts from eight different genera (Juniperus, Biota, Cupressus, Abies, Pinus, Cedrus, Populus and Corylus) to synthesize gold nanostructures (AuNSs) to understand if there is any possible marker that helps to predict the final morphology and size of the AuNSs. Principal component analysis (PCA) revealed that Apigenin and Pinoresinol compounds are the marker molecules in determination of the AuNSs physical characteristics while total protein, reducing carbohydrate, flavonoid and phenol contents did not show any statistically meaningful outcome. The dominancy hypothesis was tested by paying attention to the most concentrated phenolic acids and flavonoids in the control of AuNSs morphology and size, for which correlation analysis were performed. The statistical findings were tested using two new more pollen extracts to validate the models. Three main findings of the study were (i) determination of Apigenin and Pinoresinol levels in pollen extract can give an insight into the AuNSs physical characters, (ii) the most concentrated phenolic acids and flavonoids don't need to be same to pose same dictative effect on AuNSs morphology and size, rather relatively abundant ones in the extract play the key role and (iii) differences in the polymeric structures (e. g. lignin, cellulosic compounds etc.) have minor effect on the final morphology and size of the AuNSs. image
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    COMPARATIVE EVALUATION OF DIFFERENT EXTRACTION METHODS FOR PHYTOCHEMICAL CONTENT AND ELUCIDATION OF MICROSTRUCTURE FROM MORINGA OLEIFERA LAM
    Tepe, HD; Doyuk, F
    In this study, the effects of three different extraction methods on the antioxidant capacity, phenolic component, volatile organic molecule, and amino acid contents in the leaves of the Moringa (Moringa oleifera Lam.) were compared. The amino acid contents were evaluated via liquid chromatography -diode array detection (HPLC-DAD) analysis. In gas chromatography-mass spectrometry (GC-MS) analysis, loliolide and phytol molecules were detected in moringa leaves. Gallic acid, chlorogenic acid, 4-hydroxybenzoic acid, acid, vanillic acid, p-coumaric acid, hesperidin, hyperoside, quercetin, kaempferol were found in high amounts in moringa leaves by liquid chromatography -tandem mass spectrometry (LC-MS/MS) analysis. Tyrosine, glutamic acid, alanine, tryptophan, and L-theanine amino acids were determined by HPLC-DAD analysis. Microstructures images of three extracts were shown with Scanning Electron Microscope (SEM). Element content and mapping were demonstrated by Energy Dispersive X-ray Spectroscopy (EDX). It was found that the best extraction method is MDAE when compared to UBAE and HAE.
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    Determination of Phytochemical Content by Chromatographic Methods and Antioxidant Capacity in Methanolic Extract of Jujube (Zizyphus jujuba Mill.) and Oleaster (Elaeagnus angustifolia L.)
    Tepe, HD; Doyuk, F
    In this study, the antioxidant effects, protein contents and phytochemical structure content of jujube, oleaster fruits and their seeds were investigated. Methanol extraction of fruits and seeds was prepared and volatile organic components were examined by GC-MS and phenolic components were examined by LC-MS/MS. Antioxidant activity was determined by DPPH and NO scavenging (%). In addition, mineral content was defined with ICP-MS. DPPH scavenging activity (%) was observed most in jujube fruit (80.36%) then it continued as oleaster seed (79.33%) and oleaster fruit (72.00%) and jujube seed (66.26%) respectively. According to protein results, there was a 2.19-fold difference between jujube fruit and seed. This difference was found 0.78 times between oleaster fruit and seed. 4-hydroxybenzoic acid, gallic acid and vanillic acid contents of phenolic compounds were found in high amounts. P (phosphorus) contents in jujube, oleaster, jujube seed and oleaster seed, respectively; 722.67, 736.91, 453.74 and 687.10 mg/kg. In the jujube and jujube seed samples, the contents of Ca (calcium) were found 1261.02 and 2228.24 mg/kg. K (potassium) contents were determined 7351.16 and 7688.42 mg/kg in jujube and oleaster, respectively.
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    Simultaneous determination of six antibiotics belonging to four different classes in chicken meat BY HPLC/DAD and verification BY LC-MS/MS
    Doyuk, F; Dost, K
    The hypothesis of this study was to develop an extraction method allowing side-by-side extraction of six antibiotics belonging to four different classes and an HPLC/DAD method for the determination of their residues in chicken breast meat. The validation data showed that this hypothesis was achieved. The results were then confirmed by LC-MS/MS method. Sample preparation was based on the classical solid-liquid extraction with methanolic citric acid. The average recoveries were satisfactory and ranged from 75.68 to 101.3%. The linearity of the developed HPLC/DAD method was very high in the concentration range studied (R-2 > 0.9969). The accuracy and precision of the analytical method were between -10.8 and 12.0% relative error and 0.82 to 10.1% relative standard deviation, respectively. The LODs for five antibiotics ranged from 0.6 to 2.7 mu g kg(-1) and LOQs ranged from 2.0 to 8.9 mu g kg(-1). For penicillin G, the LOD was 0.16 and LOQ was 0.52 mg k(g-1).
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    LC-MS/MS analysis, antioxidant and anticancer effects of phenolic-rich extracts from Algerian propolis: a comparative study
    Boulechfar, S; Akbulut, Z; Tepe, HD; Zellagui, A; Aktas, RG; Bensouici, C; Doyuk, F; Khattabi, L; Demirel, G; Lahouel, M
    The present study was aimed to compare the phenolic composition and the functional properties (antioxidant and anticancer) of phenolic-rich extracts of two different propolis collected from Collo (PREPC) and Oum El Bouaghi (PREPO) regions. The phenolic composition was determined using LC/MS-MS. The antioxidant activity of the extracts was evaluated using alkaline DMSO and beta-carotene-linoleic acid tests. Anticancer effect on HepG2 human hepatocellular carcinoma cells was determined using CCK-8 assay. Twenty-two phenolic compounds in PREPC and twenty-three in PREPO were detected and quantified by LC-MS/MS. Ferulic and caffeic acids were found to be the predominant compounds. Both extracts were able to inhibit lipid peroxidation and demonstrated their ability to scavenge superoxide radicals more effectively than the standards. The highest lipid peroxidation inhibition (IC50 = 17.58 +/- 1.98 mu g/mL) and superoxide radical scavenging effects (IC50 = 6.19 +/- 0.24 mu g/mL) were exhibited by PREPO. However, PREPC showed stronger cytotoxic activity against HepG2 (IC50 = 12.22 +/- 0.05 mu g/mL) than PREPO (IC50 = 18.68 +/- 0.33 mu g/mL). These results demonstrate the potential of extracts from Algerian propolis to be used in functional formulations.