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result(s) for
"Drouza, Chryssoula"
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Insight into the Recent Application of Chemometrics in Quality Analysis and Characterization of Bee Honey during Processing and Storage
by
Mironescu, Ion Dan
,
Drouza, Chryssoula
,
Tarapoulouzi, Maria
in
Authenticity
,
bees
,
Chemical properties
2023
The application of chemometrics, a widely used science in food studies (and not only food studies) has begun to increase in importance with chemometrics being a very powerful tool in analyzing large numbers of results. In the case of honey, chemometrics is usually used for assessing honey authenticity and quality control, combined with well-established analytical methods. Research related to investigation of the quality changes in honey due to modifications after processing and storage is rare, with a visibly increasing tendency in the last decade (and concentrated on investigating novel methods to preserve the honey quality, such as ultrasound or high-pressure treatment). This review presents the evolution in the last few years in using chemometrics in analyzing honey quality during processing and storage. The advantages of using chemometrics in assessing honey quality during storage and processing are presented, together with the main characteristics of some well-known chemometric methods. Chemometrics prove to be a successful tool to differentiate honey samples based on changes of characteristics during storage and processing.
Journal Article
Enhancement of the Anti-Inflammatory Activity of NSAIDs by Their Conjugation with 3,4,5-Trimethoxybenzyl Alcohol
by
Papagiouvannis, Georgios
,
Petrou, Anthi
,
Drouza, Chryssoula
in
Alcohol
,
Amino acids
,
Amino Acids - therapeutic use
2022
The synthesis of derivatives of three nonspecific COX-1 and COX-2 inhibitors, ibuprofen, ketoprofen, naproxen is presented. These acids were connected via an amide bond with an amino acid (L-proline, L-tyrosine, and beta-alanine) used as a linker. The amino acid carboxylic group was esterified with 3,4,5 trimethoxybenzyl alcohol. The activity of the novel derivatives was examined in vivo on carrageenan-induced inflammation, and in vitro, as cyclooxygenase and lipoxygenase inhibitors. It was found that the new compounds were more potent anti-inflammatory agents than the parent drugs. Thus, the ibuprofen (21) and ketoprofen (16) derivatives reduced rat paw edema by 67 and 91% (the reduction by the relevant NSAIDs was 36 and 47%, respectively). They inhibited COX-2 more than the starting drugs (21 by 67%, ibuprofen 46%, 19 by 94%, ketoprofen 49%). Docking of compounds on the active sites of COX-1 and COX-2 reflects their in vitro activity. Thus, 19 adopts an unfavorable orientation for COX-1 inhibition, but it binds effectively in the binding pocket of COX-2, in agreement with the absence of activity for COX-1 and the high inhibition of COX-2. In conclusion, the performed structural modifications result in the enhancement of the anti-inflammatory activity, compared with the parent NSAIDs.
Journal Article
Traditionally Used Sideritis cypria Post.: Phytochemistry, Nutritional Content, Bioactive Compounds of Cultivated Populations
by
Tzortzakis, Nikolaos
,
Tomou, Ekaterina-Michaela
,
Chrysargyris, Antonios
in
Antioxidants
,
Bioactive compounds
,
Carbohydrates
2020
Sideritis species are recognized as important medicinal plants and their commercial demand is continuously on the rise both in the European and in the global market. Consequently, the cultivation of Sideritis species has been occurred to successfully meet the need for mass production of high-quality plant material. The present study was undertaken in order to investigate the chemical composition of cultivated S. cypria . Infusions of flowers and leaves were prepared separately, according to the European Medicine Agency (EMA) monograph. The infusion of the flowers revealed the presence of four flavones, isoscutellarein-7-O-[6′″-O-acetyl-β-D-allopyranosyl-(1→2)-β-D-glucopyranoside, its 4′-O-methyl-derivative, 4′-O-methyl-hypolaetin-7-O-[6′″-O-acetyl-β-D-allopyranosyl-(1→2)-β-D-glucopyranoside, and isoscutellarein-7-O-[6′″-O-acetyl-β-D-allopyranosyl-(1→2)]-6″-O-acetyl-β-D-glucopyranoside; four phenylethanoid glucosides, acteoside, leucosceptoside A, lamalboside, and leonoside A; one iridoid, melittoside, and one phenolic acid, chlorogenic acid, while the infusion of the leaves of the same population afforded the same first two flavones; five phenylethanoid glucosides, acteoside, leucosceptoside A, lavandulifolioside, leonoside A, and lamalboside; melittoside and chlorogenic acid. The structural elucidation of the isolated compounds was undertaken by high-field NMR spectroscopy. Moreover, the essential oils of the flowers and leaves were studied by GC-MS, separately. In addition, the mineral, bioactive compounds, protein and carbohydrate contents were evaluated for both plant materials.
Journal Article
Characterization and Botanical Differentiation of Monofloral and Multifloral Honeys Produced in Cyprus, Greece, and Egypt Using Physicochemical Parameter Analysis and Mineral Content in Conjunction with Supervised Statistical Techniques
by
Karabagias, Ioannis K.
,
Kontakos, Stavros
,
Louppis, Artemis P.
in
acidity
,
Agriculture
,
Aluminum
2018
Thirty-four honey samples donated by beekeepers and purchased from supermarkets were collected during harvesting years 2010–2014 from Cyprus, Greece, and Egypt. The aims of this study were to characterize honey samples and, if possible, to differentiate honeys according to the honey type on the basis of physicochemical parameter values, mineral content, and their combination using supervised statistical techniques (linear discriminant analysis (LDA)). Physicochemical parameters (colour, pH, free acidity, total dissolved solids, salinity, electrical conductivity, and moisture content) were determined according to official methods, while minerals (Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, P, Pb, Sb, Si, Ti, Tl, V, and Zn) using inductively coupled plasma optical emission spectrometry. The majority of honey samples analyzed met the quality criteria set by the European directive and national decision related to honey. Implementation of multivariate analysis of variance (MANOVA) and LDA on specific physicochemical parameters, minerals, or their combination provided a satisfactory classification of honeys according to floral type. The overall correct classification rate (based on the cross-validation method) was 79.4% using 7 minerals and 91.2% using 8 physicochemical parameters. When the 15 parameters were combined, the classification rate of Egyptian honeys was improved by 25%.
Journal Article
Vanadium(V) Complexes with Siderophore Vitamin E-Hydroxylamino-Triazine Ligands
by
Simos, Yannis V.
,
Drouza, Chryssoula
,
Hadjiadamou, Ioanna
in
51V NMR
,
Biological activity
,
Biological properties
2021
Novel vitamin E chelate siderophore derivatives and their VV and FeIII complexes have been synthesised and the chemical and biological properties have been evaluated. In particular, the α- and δ-tocopherol derivatives with bis-methyldroxylamino triazine (α-tocTHMA) and (δ-tocDPA) as well their VV complexes, [V2VO3(α-tocTHMA)2] and [V2IVO3(δ-tocTHMA)2], have been synthesised and characterised by infrared (IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and ultra violet-visible (UV-Vis) spectroscopies. The dimeric vanadium complexes in solution are in equilibrium with their respefrctive monomers, H2O + [V2VO2(μ-O)]4+ = 2 [VVO(OH)]2+. The two amphiphilic vanadium complexes exhibit enhanced hydrolytic stability. EPR shows that the complexes in lipophilic matrix are mild radical initiators. Evaluation of their biological activity shows that the compounds do not exhibit any significant cytotoxicity to cells.
Journal Article
Low-temperature winemaking by thermally dried immobilized yeast on delignified brewer's spent grains
by
Koutinas, Athanasios A
,
Drouza, Chryssoula
,
Bosnea, Loulouda
in
Alcohol
,
brewer’s spent grains
,
Drying
2011
Preservation, risk of contamination, transportation and storage costs (e.g. refrigeration) are the main problems associated with wet, active starter cultures such as yeast. To deal with these aspects, drying of commercial cultures is required. A thermally dried biocatalyst has been prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on delignified brewer's spent grains, followed by simple thermal drying or by air stream at 30 and 35 °C. Repeated batch fermentations of grape must (11.5 °Be, corresponding to 196 g/L of fermentable sugar) using the dried biocatalysts were performed at successively reduced temperatures (15, 10 and 5 °C). The fermented samples were analyzed for residual sugar, alcohol and free cell concentrations. The alcohol yield, alcohol productivity and sugar conversion were calculated in order to estimate the optimum conditions of drying. The volatile constituents in the produced wines were analysed by GC analysis. The results showed that drying of immobilized cells by the proposed techniques did not affect their viability and fermentative activity. High alcohol productivity, increased esters and lower concentrations of higher alcohols obtained by low-temperature fermentation using the dried biocatalysts indicate a potential improvement of product quality. Key words: brewer's spent grains, immobilization, thermal drying, winemaking
Journal Article
Geographical discrimination of pine and fir honeys using multivariate analyses of major and minor honey components identified by 1H NMR and HPLC along with physicochemical data
by
Kontakos, Stavros
,
Kontominas, Michael G
,
Drouza, Chryssoula
in
Amino acids
,
Apiculture
,
Beekeeping
2018
The objective of the present work was the geographical discrimination of the most common honeydew honeys produced in Greece, namely pine and fir, on the basis of sugar, free amino acid and organic acid content, determined by nuclear magnetic resonance spectroscopy (1H NMR) and high-performance liquid chromatography (HPLC), along with moisture content, sugar ratios, or sugars to moisture ratio, using chemometrics. For this purpose, 39 pine and 31 fir honey samples were collected from professional beekeepers from eight different regions in Greece. Data were subjected to multivariate analysis and modeled using supervised statistical methods. The combination of 1H NMR and HPLC based on metabolites along with the aforementioned physicochemical data resulted in the geographical discrimination of pine and fir honeys. Respective prediction rates were 76.9 and 80.6%, using a model validation technique: the cross-validation method. Present results support the combined use of instrumental and conventional methods for honey geographical origin differentiation.
Journal Article
pH-Potentiometric Investigation towards Chelating Tendencies of p-Hydroquinone and Phenol Iminodiacetate Copper(II) Complexes
by
Chryssoula Drouza
,
Anastasios D. Keramidas
,
Marios Stylianou
in
Agricultural production
,
Binding sites
,
Complexation
2010
Copper ions in the active sites of several proteins/enzymes interact with phenols and quinones, and this interaction is associated to the reactivity of the enzymes. In this study the speciation of the Cu2+ with iminodiacetic phenolate/hydroquinonate ligands has been examined by pH-potentiometry. The results reveal that the iminodiacetic phenol ligand forms mononuclear complexes with Cu2+ at acidic and alkaline pHs, and a binuclear Ophenolate-bridged complex at pH range from 7 to 8.5. The binucleating hydroquinone ligand forms only 2 : 1 metal to ligand complexes in solution. The pK values of the protonation of the phenolate oxygen of the two ligands are reduced about 2 units after complexation with the metal ion and are close to the pK values for the copper-interacting tyrosine phenol oxygen in copper enzymes.
Journal Article
Synthesis, Solution, and Structural Characterization of Tetrahydrofuranyl-2,2-Bisphosphonic Acid Disodium Salt
by
Elena Maltezou
,
Chryssoula Drouza
,
Anastasios D. Keramidas
in
Acids
,
Agricultural production
,
Aqueous solutions
2010
Bisphosphonates are biologically relevant therapeutics for bone disorders and cancer. Reaction of γ-chlorobutyric acid, phosphorus acid, and phosphorus trichloride without the use of solvent gave the tetrahydrofuranyl-2,2-bisphosphonate sodium salt (Na2H2L). The Na2H2L was isolated, characterized in solution by 1H, 13C, and 31P NMR spectroscopy and in solid state by single X-Ray crystallography. The crystal structure showed that the Na2H2L forms in the crystal infinite two-dimensional sheets stacked one parallel to the other. A comparison of the chelating properties of H2L2− with similar hydroxyl bisphosphonate ligands shows that the strength of the Na–O(furanyl/hydroxyl) bond is directly related to the total charge of the ligand anion.
Journal Article
Structural and electron paramagnetic resonance (EPR) characterization of novel vanadium(V/IV) complexes with hydroquinonate-iminodiacetate ligands exhibiting “noninnocent” activity
by
Drouza, Chryssoula
,
Papaphilippou, Petri
,
Stylianou, Marios
in
Aqueous solutions
,
Binding sites
,
Chelates
2013
Reaction of KVO
with 2-[
'-(carboxymethyl)aminomethyl]-5-methylhydroquinone (H
mecah) in aqueous solution at pH 8.2 results in the isolation of mononuclear K
[V
(O)
{Hmecah(-3)}]·2H
O complex. On the other hand, reaction with the 2-[
'-(carboxymethyl)aminomethyl]-5-
butylhydroquinone (H
butcah) under the same conditions gives the tetranuclear mixed-valent complex K
[{V
O(
-O)V
O}{
butbicah(-6)}]
·10.5H
O (H
butbicah, 2,2'-({2-[bis(carboxymethyl)amino]-3,6-dihydroxy-4-methylbenzyl}azanediyl)diacetic acid). The structures of both complexes were determined by single-crystal X-ray crystallography. The coordination environment of vanadium ions in both complexes is octahedral, with four out of the six positions to be occupied by the two
carboxylate oxygens, one hydroquinonate oxygen, and one amine nitrogen atoms of the ligands’ tripod binding sites. The importance of the chelate ring strains in the stabilization of the
-semiquinone radical is also discussed. A protonation of the ligated to vanadium(IV) ion hydroquinonate oxygen at low pH was revealed by continuous wave (cw) X-band electron paramagnetic resonance (EPR) and UV–vis spectroscopies.
Journal Article