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42
result(s) for
"Simova, Svetlana"
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Synergistic Solvent Extraction of Lanthanoids with Traditional Ligands (4-Acylpyrazolone and Bidentate Nitrogen Bases) in a Nontraditional Diluent Confirmed by Slope Analysis and NMR
by
Todorova, Nina
,
Simova, Svetlana
,
Atanassova, Maria
in
1,10-phenanthroline
,
2,2′-bipyridine
,
4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one
2025
The synergistic solvent extraction of La(III), Eu(III) and Lu(III) with a chelating extractant, 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HL), and neutral bidentate heterocyclic amines, such as 1,10-phenanthroline (S1 (phen)) or 2,2′-bipyridine (S2 (bipy)) in an ionic liquid of the imidazolium family [C1C4im+][Tf2N−] was investigated. Synergistic effects have been observed to result from the formation of a ternary complex in the organic phase, particularly in cases where the ligand S is a neutral synergistic agent. Examples include La(L)2(S2)2, Eu(L)3(S2) and Lu(L)x(S2)2, as well as La(L)3(S1)2, Eu(L)2(S1) and Lu(L)3(S1)x). The parameters of the solvent extraction process were determined and the influence of the synergistic agent on the extraction process was discussed. Additionally, the synergistic increase and separation factors were determined. The equilibrated organic phases were analyzed using 1H NMR spectroscopy to elucidate the synergism in an extraction mechanism. The role of the ionic diluent in complexation processes and selectivity was investigated with the employment of the two synergistic agents for various metal s-, p-, d- and f-cations in the periodic table, with almost 22 metal ions.
Journal Article
Optical Rotation—A Reliable Parameter for Authentication of Honey?
by
Kurteva, Vanya
,
Gerginova, Dessislava
,
Simova, Svetlana
in
13C NMR
,
botanical origin
,
Chemical properties
2022
The controversial question of whether optical rotation data can be used to distinguish floral from honeydew honey was investigated. Specific optical rotation angles were determined for 41 honey samples, including floral, honeydew, and adulterated honey, indicating that moderate to high positive optical rotation angles were found for all adulterated samples measured. A strong correlation between the sugar profile and the specific optical rotation angle of honey was confirmed, and a method based on 13C NMR metabolomics was proposed to calculate specific optical rotation angles with good correlation with the experimental values. The results indicate that optical rotation is not a reliable method for distinguishing the origin of honey but could indicate adulteration.
Journal Article
Phytochemical Profile, Antioxidant Potential, Antimicrobial Activity, and Cytotoxicity of Dry Extract from Rosa damascena Mill
by
Atanasov, Nikola
,
Nikolova, Dilyana
,
Rasheva, Iliyana
in
Acids
,
antimicrobial activity
,
Antimicrobial agents
2023
Dry rose extract (DRE) obtained industrially by aqueous ethanol extraction from R. damascena flowers and its phenolic-enriched fraction, obtained by re-extraction with ethyl acetate (EAE) were the subject of this study. 1H NMR of DRE allowed the identification and quantitation of fructose and glucose, while the combined use of HPLC-DAD-ESIMS and HPLC-HRMS showed the presence of 14 kaempferol glycosides, 12 quercetin glycosides, 4 phenolic acids and their esters, 4 galloyl glycosides, 7 ellagitannins, and quinic acid. In addition, the structures of 13 of the flavonoid glycosides were further confirmed by NMR. EAE was found to be richer in TPC and TFC and showed better antioxidant activity (DPPH, ABTS, and FRAP) compared to DRE. Both extracts displayed significant activity against Propionibacterium acnes, Staphylococcus aureus, and S. epidermidis, but showed no activity against Candida albicans. Toxicity tests on normal human skin fibroblasts revealed low toxicity for both extracts with stronger effects observed at 24 hours of treatment that were compensated for over the following two days. Human hepatocarcinoma (HepG2) cells exhibited an opposite response after treatment with a concentration above 350 µg/mL for EAE and 500 µg/mL for DRE, showing increased toxicity after the third day of treatment. Lower concentrations were non-toxic and did not significantly affect the cell cycle parameters of either of the cell lines.
Journal Article
Weiss or Wit: Chemical Profiling of Wheat Beers via NMR-Based Metabolomics
by
Gerginova, Dessislava
,
Chorbadzhiev, Plamen
,
Simova, Svetlana
in
Alcohol
,
Alcohols
,
Amino acids
2025
Wheat beers, including Witbier, Hefeweizen, and Weizenbock, are known for their unique sensory profiles, which are shaped by the combination of ingredients, fermentation conditions, and brewing methods. In this study, we used nuclear magnetic resonance (NMR) spectroscopy to explore the metabolomic signatures of various wheat beer styles and substyles. By analyzing 39 beer samples from 17 countries, we identified and quantified 50 metabolites, ranging from alcohols and saccharides to amino acids and organic acids. Ethanol and maltodextrin were the most abundant compounds, while higher contents of alcohols and organic acids played a key role in flavor variation. Through orthogonal partial least squares discriminant analysis (OPLS-DA), we achieved an impressive 97.44% accuracy in distinguishing between Witbier, Hefeweizen, and Weizenbock based on their metabolic profiles. The analysis also revealed notable compositional differences between craft and commercial beers, with craft beers showing higher concentrations of alcohols and amino acids. These results underscore the significant impact of raw materials, fermentation parameters, and brewing techniques on the chemistry of wheat beer. Furthermore, this study highlights the potential of NMR spectroscopy as a powerful tool for beer authentication and quality control.
Journal Article
Barley Wine in Focus: NMR Metabolomics Reveals Style and Barrel Aging Differences
by
Gerginova, Dessislava
,
Chorbadzhiev, Plamen
,
Simova, Svetlana
in
Acetaldehyde
,
Aging
,
Alcohol
2025
Barley wine is one of the most chemically complex and historically significant beer styles, yet its molecular composition remains largely unknown. This study aims to create the first detailed molecular framework for understanding the chemical diversity of barley wine and cereal wines. The chemical diversity of barley wines and related “cereal wines” made from wheat, oats, and rye, including barrel-aged varieties, is examined using 1H nuclear magnetic resonance (NMR) metabolomics. Distinct cereal-dependent signatures were revealed by multivariate analyses. High levels of fusel alcohols and phenolic acids were present in barley wines. Elevated levels of pyruvate and aromatic amino acids were found in wheat wines, and high levels of maltodextrin, arabinose, and trigonelline were found in oat and rye wines. A comparison of sub-styles showed that English and American barley wines were different based on ester and complex sugar profiles. Barrel aging introduces changes dependent on the barrel’s origin. A reliable classification of barrel origin was allowed for by a decision tree with four diagnostic metabolites—5-hydroxymethylfurfural (HMF), acetaldehyde, mannose, and tryptophan. The way in which raw materials, fermentation conditions, and the reuse of barrels collectively influence their metabolomes is exemplified. Verifying the authenticity of beer, evaluating its quality, and generating new ideas for high gravity brewing are all cases in point for this approach.
Journal Article
Integrated Spectroscopic Analysis of Wild Beers: Molecular Composition and Antioxidant Properties
2025
Wild ales represent a diverse category of spontaneously fermented beers, influenced by complex microbial populations and variable ingredients. This study employed an integrated metabolomic profiling approach combining proton nuclear magnetic resonance (1H NMR) spectroscopy, liquid chromatography–mass spectrometry (LC-MS), and spectrophotometric assays (DPPH and FRAP) to characterize the molecular composition and antioxidant potential of 22 wild ales from six countries. A total of 53 compounds were identified and quantified using NMR, while 62 compounds were identified by using LC-MS. The compounds in question included organic acids, amino acids, sugars, alcohols, bitter acids, phenolic compounds, and others. Ingredient-based clustering revealed that the addition of dark fruits resulted in a significant increase in the polyphenolic content and antioxidant activity. Concurrently, herb-infused and light-fruit beers exhibited divergent phytochemical profiles. Prolonged aging (>18 months) has been demonstrated to be associated with increased levels of certain amino acids, fermentation-derived aldehydes, and phenolic degradation products. However, the influence of maturation duration on the antioxidant capacity was found to be less significant than that of the type of fruit. Country-specific metabolite trends were revealed, indicating the influence of regional brewing practices on beer composition. Correlation analysis was employed to identify the major contributors to antioxidant activity, with salicylic, dihydroxybenzoic, and 4-hydroxybenzoic acids being identified as the most significant. These findings underscore the biochemical intricacy of wild ales and exemplify metabolomics’ capacity to correlate compositional variation with functionality and authenticity in spontaneously fermented beverages.
Journal Article
NMR Profiling of North Macedonian and Bulgarian Honeys for Detection of Botanical and Geographical Origin
by
Stefova, Marina
,
Gerginova, Dessislava
,
Stanoeva, Jasmina Petreska
in
Bulgaria
,
Cheminformatics - methods
,
classification
2020
Bulgaria and North Macedonia have a long history of the production and use of honey; however, there is an obvious lack of systematic and in-depth research on honey from both countries. The oak honeydew honey is of particular interest, as it is highly valued by consumers because of its health benefits. The aim of this study was to characterize honeydew and floral honeys from Bulgaria and North Macedonia based on their NMR profiles. The 1D and 2D 1H and 13C-NMR spectra were measured of 16 North Macedonian and 22 Bulgarian honey samples. A total of 25 individual substances were identified, including quinovose, which was found for the first time in honey. Chemometric methods (PCA—principal component analysis, PLS-DA—partial least squares discriminant analysis, ANOVA—analysis of variance) were used to detect similarities and differences between samples, as well as to determine their botanical and geographical origin. Semiquantitative data on individual sugars and some other constituents were obtained, which allowed for the reliable classification of honey samples by botanical and geographical origin, based on chemometric approaches. The results enabled us to distinguish oak honeydew honey from other honey types, and to determine the country of origin. NMR was a rapid and convenient method, avoiding the need for other more time-consuming analytical techniques.
Journal Article
A Preliminary Study of Chemical Profiles of Honey, Cerumen, and Propolis of the African Stingless Bee Meliponula ferruginea
by
Popova, Milena
,
Ceylan, Ozgur
,
Bankova, Vassya
in
African Meliponini
,
Antiinfectives and antibacterials
,
Apis mellifera
2021
Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Meliponula ferruginea from Tanzania. The honey of M. ferruginea was profiled by NMR and indicated different long-term stability from Apis mellifera European (Bulgarian) honey. It differed significantly in sugar and organic acids content and had a very high amount of the disaccharide trehalulose, known for its bioactivities. We suggested trehalulose to be a potential marker for African stingless bee honey analogously to the recent proposal for Meliponini honey from Asia, South America, and Australia and demonstrated its easy discrimination by 13C NMR. Propolis and cerumen were studied by GC-MS (gas chromatography-mass spectometry). The samples contained mainly terpenoids (di-and triterpenes) but demonstrated qualitative and quantitative differences. This fact was an indication that possibly M. ferruginea has no strict preferences for resins used to construct and protect their nests. The antimicrobial and anti-quorum sensing properties of the two materials were also tested. These first results demonstrated that the honey, cerumen, and propolis of African stingless bees were rich in biologically active substances and deserved further research.
Journal Article
Heteronuclear Complexes of Hg(II) and Zn(II) with Sodium Monensinate as a Ligand
by
Kolev, Stiliyan
,
Pantcheva, Ivayla
,
Dorkov, Petar
in
Acids
,
Anti-Bacterial Agents - chemistry
,
Anti-Bacterial Agents - pharmacology
2024
The commercial veterinary antibiotic sodium monensinate (MonNa) binds mercury(II) or zinc(II) cations as thiocyanate [Hg(MonNa)2(SCN)2] (1) or isothiocyanate [Zn(MonNa)2(NCS)2] (2) neutral coordination compounds. The structure and physicochemical properties of 1 and 2 were evaluated by the methods of single crystal and/or powder X-ray diffraction, infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopies, and electrospray-mass spectrometry. The primary cores of the two complexes comprise HgS2O2 (1) and ZnN2O2 (2) coordination motifs, respectively, due to the ambidentate binding modes of the SCN–ligands. The directly bound oxygen atoms originate from the carboxylate function of the parent antibiotic. Sodium cations remain in the hydrophilic cavity of monensin and cannot be replaced by the competing divalent metal ions. Zinc(II) binding does not influence the monensin efficacy in the case of Bacillus cereus and Staphylococcus aureus whereas the antimicrobial assay reveals the potential of complex 2 as a therapeutic candidate for the treatment of infections caused by Bacillus subtilis, Kocuria rhizophila, and Staphylococcus saprophyticus.
Journal Article
Metabolomic Nuclear Magnetic Resonance Insights into Wine and Grape Ale Maturation
2025
The chemical profiles of young and mature wines produced from three grape varieties Merlot, Mavrud, and Sauvignon blanc were analyzed using 1H nuclear magnetic resonance (NMR) spectroscopy and advanced statistical methods. Furthermore, grape ales―a hybrid of beer and wine—were subjected to analysis to facilitate a comparison of their composition with that of traditional wines. The analysis yielded a total of 37 compounds, which were identified and quantified. Orthogonal partial least squares discriminant analysis (OPLS-DA) models were employed to distinguish the chemical profiles of young and mature wines, as well as those of grape ales. The findings demonstrate that the fermentation and aging processes result in the formation of distinctive chemical signatures in wines, with key compounds such as shikimic acid and fructose contributing to this differentiation. The identified compounds comprise seven alcohols (2,3-butanediol, glycerol, 2-methylpropan-1-ol, 3-methyl-butan-1-ol, myo-inositol, 1-propanol, 2-phenylethanol), six organic acids (galacturonic, citric, lactic, malic, shikimic, succinic), three amino acids (alanine, proline, tyrosine), four sugars (arabinose, fructose, galactose, glucose), coutaric acid, and acetoin. The levels of these 22 components enabled the successful differentiation of young and mature wines among the three grape varieties. These findings underscore the substantial chemical distinctions between grape ales and wines, thereby emphasizing the potential of grape ales as an innovative fermented beverage.
Journal Article