Institute of Chemistry
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Item type:Publication, Pharmacokinetics of different selenium supplements in healthy individuals and patients with autoimmune thyroiditis after oral administration(Society of Chemists and Technologists of Macedonia, 2025-06-24); ; ; Stafilov, TrajčeSelenium is essential for the function of key selenoproteins such as glutathione peroxidase, thiore-doxin reductase, and iodothyronine deiodinase, which have antioxidant properties and support thyroid hormone metabolism. Due to the low selenium content in European soils – particularly in the Southeast-ern regions, supplementation is often recommended, especially for conditions like Hashimoto's thyroidi-tis. However, careful consideration of selenium dosage and pharmacokinetics is crucial, as the margin be-tween essential and toxic levels is very narrow. The aim of this study was to investigate the pharmacoki-netics of selenium absorption and plasma concentration following oral administration of various selenium doses and chemical forms, both in the short and long term, in healthy individuals and patients with auto-immune thyroiditis. Selenium concentrations in blood plasma were measured using electrothermal atomic absorption spectrometry (ETAAS). The study found that L-selenomethionine is absorbed more efficiently than inorganic sodium selenite, with peak plasma concentrations reached and sustained within 6 – 8 hours. Selenium levels remained elevated 48 hours after ingestion compared to baseline. At a daily dose of 200 μg of selenium as L-selenomethionine, plasma selenium concentrations increased by approximate-ly 30 %, and by about 25 % at 100 μg/day, relative to the initial value. Long-term studies showed that plasma selenium concentrations rose significantly after the first month of supplementation, with a slower increase in subsequent months. After supplementation ended, selenium levels declined rapidly. Interest-ingly, no significant differences in selenium absorption or excretion were observed between patients with Hashimoto's thyroiditis and healthy controls. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Unmasking the Aliphatic Repertoire: New Polyunsaturated Metabolites in Bupleurum falcatum sensu lato Provide Chemotaxonomic Insights(MDPI AG, 2025-05-10); Radulović, Niko S.Bupleurum falcatum (Apiaceae) sensu lato includes multiple infraspecific taxa with longstanding taxonomic ambiguities, often resulting from incomplete morphological and chemical characterizations. Herein, diethyl ether extracts were analyzed from four Balkan populations that were tentatively identified as B. falcatum subsp. falcatum (syn. B. falcatum) and B. falcatum subsp. cernuum (syn. B. sibthorpianum). Comprehensive chro-matography and spectroscopic techniques (GC-MS and 1D/2D NMR) enabled the iso-lation of several newly identified aliphatic polyunsaturated esters, including com-pounds bearing uncommon conjugated tetraene and triyne backbones. These novel structures differ from canonical falcarinol derivatives by lacking the usual 3-hydroxylation, suggesting a divergent branch in the crepenynate pathway. The chemical profiles of each sample correlated closely with leaf morphology and infra-specific designations: for example, the Galičica Mt. population of B. falcatum featured a unique newly detected heptadecadientriyne, while the populations from Šar Planina and Suva Planina displayed distinct polyunsaturated repertoires. Extracts from B. sibthorpianum likewise contained stereoisomeric compounds that highlight metabolic divergence. Collectively, these findings demonstrate significant chemotypic variation within the Bupleurum falcatum complex and provide the first account of less-polar sec-ondary metabolites, including newly discovered polyunsaturated metabolites. Future research integrating molecular markers and bioactivity assays may elucidate how these specialized metabolites contribute to both the taxonomy and pharmacological potential of these understudied taxa. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Upcycling of plastic waste into multi-walled carbon nanotubes as efficient organic dye adsorbent(Slovenian Chemical Society, 2025-03-03); ; Kovačič, SebastijanMulti-walled CNTs with an average diameter of about 80 nm, a length of several micrometers and surface area (SBET) of 100 m2 g-1 were obtained by pyrolysis of low-density polyethylene waste. The potential of the resulting MWCNTs material to purify water containing organic dyes was tested with Bezaktiv Blau HE-RM (BB) and Bezaktiv Rot S-3B (BR) reactive dyes. 200 mg L-1 MWCNT material was used to follow the adsorption of 30 mg L-1, 40 mg L-1, 50 mg L-1 and 60 mg L-1 BB and BR at pH 3 and a temperature of ~25 oC. The results have shown that this material has a high potential as a sorbent, and its adsorption capacity of 257 mg g-1 (for Bezaktiv Blau HE-RM) and 213 mg g-1 (for Bezaktiv Rot) is close to some commercial MWCNTs and functionalized MWCNT-based adsorbents. The adsorption process was very fast, reaching 80-90 % of the dye removal in 10-15 minutes, and the equilibrium time was reached in 40-60 minutes. The adsorption isotherm showed that the Langmuir model was more suitable than the Freundlich model for describing the adsorption properties of the pollutants. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Infrared and Raman spectra of racemic ibuprofen sodium dihydrate – Spectra-structure correlations(Elsevier BV, 2025-10) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Assessment of volatile organic compounds in indoor environments across North Macedonia and Kosovo using passive sampling(Society of Chemists and Technologists of Macedonia, 2024-12-28); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Vasorelaxant Effects of Ethanolic Extract from <i>Cydonia oblonga</i> Mill<i>.</i> Leaves on Isolated Rat Thoracic Aorta and Potential Mechanism of Action(SAGE Publications, 2024-09) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Crossroads of vibrational (infrared and Raman) spectroscopy and X-ray powder diffraction in identification and characterization of some minerals – advantages and limitations. A review(Society of Chemists and Technologists of Macedonia, 2024-05-19); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Coal: exploration, reserves, and utilization(Springer Science and Business Media LLC, 2024-02-12) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Raman spectroscopy as a tool for predicting the dimensionality and octahedra connectivity in lead iodide perovskites(2023-12-05)Gjorgjevikj, K., Bukleski, M., Dimitrovska-Lazova, S., Aleksovska, S.The interesting properties of the perovskite materials, especially the organic-inorganic ones are a consequence of their structural characteristics. In order to define the origin of these properties, a detailed structural characterization involving analysis with vibrational spectroscopy techniques has been undertaken. In this work, several inorganic and organic-inorganic lead iodide perovskites (RbPbI3, CsPbI3, CH3NH3PbI3, CH(NH2)2PbI3, C(NH2)3PbI3, (CH3)2NH2PbI3, (CH2)4NH2PbI3) were investigated by means of vibrational spectroscopy at room and low temperature and X-ray powder diffraction. Focusing on the Raman spectra, we followed the differences appearing in perovskites with different dimensionality. The bands that occur below 200 cm–1, their shape, relative position, intensity and shift can be related to the octahedral connectivity of the PbI6 anions, which, on the other hand, influence the dimensionality of the perovskites. Therefore, Raman spectroscopy can be used as a supporting technique for fast and reliable identification of octahedral connectivity. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Rapid and in-situ determination of epoxy equivalent weight of bisphenol-based epoxides by micro-Raman spectroscopy(Springer Science and Business Media LLC, 2023-02);