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State of antioxidant systems and phenolic compounds’ production in Hypericum perforatum L. hairy roots
(Springer Science and Business Media LLC, 2019-07-09)
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Spasenoski, Mirko
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Gadzovska Simic, Sonja
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HPLC method validation and application for organic acid analysis in wine after solid-phase extraction
(Society of Chemists and Technologists of Macedonia, 2016-12-27)
Ivanova-Petropulos, Violeta
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Tašev, Krste
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<jats:p>A solid-phase extraction method followed by reverse phase high-performance liquid chromatography (RP-HPLC) was optimized and validated for the quantitative determination of tartaric, malic, shikimic, lactic, citric and succinic acids in wine. Solid-phase extraction was carried out with C18 cartridges and extraction recoveries for all acids ranging from 98.3 to 103% were obtained. HPLC separation was performed with isocratic elution on a LiChrosorb RP-18 column (250 × 4.6 mm I.D., 5 µm) protected with the appropriate guard column. The mobile phase was a 5 mM solution of H3PO4 with pH 2.1 at a flow rate of 1 ml/min. Detection of the organic acids was performed at 210 nm. The developed method was validated by checking its linearity, limit of detection (LOD), limit of quantification (LOQ), precision and recovery. The method was applied to the analysis of organic acids in Macedonian red and white wines.</jats:p>
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Comparison of different extraction solvents for assay of the polyphenol content in the peel and pulp of 21 apple cultivars from Macedonia
(Society of Chemists and Technologists of Macedonia, 2016-04-18)
Petkovska, Ana
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Gjamovski, Viktor
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<jats:p>Apples (Malus domestica Borkh.) contain a large array of phenolic compounds belonging to flavonoids and non-flavonoids. This study systematically evaluates the polyphenolic content of 21 apple cultivars from the Republic of Macedonia, both commercial and autochthonous, applying spectrophotometric methods for the determination of total polyphenolic compounds, total flavonoids, total anthocyanins and total flavan-3-ols. The reliability of these methods was checked by confirming the method linearity and accuracy with standards and spiked samples. The efficiency of acetone, water, methanol and a mixture of methanol/water (90 : 10, V/V) as extraction solvents was compared. Evident differences between extracts obtained from freeze-dried apple peel and pulp, extracted with different solvents, and analyzed with the four spectrophotometric tests, were observed and discussed. The most satisfactory extraction efficiency was achieved using methanol/water (90 : 10, V/V) mixture. The results obtained from the methanol/water extracts illustrate evident differences between polyphenol contents and reveal the diversity in polyphenols, total flavonoid and flavanol composition between the assayed commercial and autochthonous cultivars. The maximum abundance of polyphenols was noticed in the peel of Tetovka and Livadarka cultivars (15.63 mg/g GAE and 14.85 mg/g GAE, respectively) and in the pulp of Pasalma, Tetovka and Livadarka cultivars (12.55 mg/g GAE, 11.45 mg/g GAE and 11.22 mg/g GAE, respectively).</jats:p>
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Agrobacterium enhances xanthone production in Hypericum perforatum cell suspensions
(Springer Science and Business Media LLC, 2014-10-08)
Tusevski, Oliver
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Petreska Stanoeva, Jasmina
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Gadzovska Simic, Sonja
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Chemotaxonomic contribution to the Sideritis species dilemma on the Balkans
(Elsevier BV, 2015-08)
Stanoeva, Jasmina Petreska
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Stefkov, Gjose
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Alipieva, Kalina
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Simultaneous Determination of Essential Oil Components and Fatty Acids in Fennel using Gas Chromatography with a Polar Capillary Column
(SAGE Publications, 2015-09)
Najdoska-Bogdanov, Menče
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Bogdanov, Jane B.
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<jats:p> Cultivated and wild growing samples of fennel ( Foeniculum vulgare Mill., Apiaceae) from R. Macedonia were studied for their volatiles and fatty acid composition. The main essential oil components isolated via hydrodistillation were: trans-anethole (>80%), estragole (<6%), limonene (<6%), anisaldehyde (<1%) and 0.5 % fenchone. An alternative method for characterization of both the non-polar volatile and non volatile fractions was developed using n-hexane and dichloromethane (3:1, v/v) in a Soxhlet extraction followed by transesterification. The obtained extracts were then characterized and the dominant fatty acid was 18:1 (petroselinic and oleic acid) 75.0–82.8 %, followed by 18:2 (linoleic acid) 10.8–16.2% and other fatty acids: palmitic (4.3–6.9%), stearic (1.2–1.7%) and myristic (0–2.9%). The results for the volatile fraction after Soxhlet extraction and transesterification did not significantly differ from results obtained after hydrodistillation, especially for the main components ( trans-anethole, estragole, fenchone and limonene), implying that the developed method can be used for simultaneous determination of volatiles and fatty acids. </jats:p>
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Flavonoids and Other Phenolic Compounds in Needles of Pinus peuce and Other Pine Species from the Macedonian Flora
(SAGE Publications, 2015-06)
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Stefkov, Gjose
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Stanoeva, Jasmina Petreska
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<jats:p> Flavonoids and other phenolic compounds in young needles of four pine species, Pinus peuce, P. nigra, P. mugo and P. sylvestris from the Macedonian flora were investigated. The amount of total phenols and total flavonoids were determined using Folin-Ciocalteau and aluminum chloride assay, respectively. The obtained results revealed that the total phenolic content (TPC) and total flavonoids content (TFC) varied among different pine species ranging from 9.8 to 14.0 mg GAE/g and from 3.3 to 7.2 mg CE/g of dried plant material, respectively. Qualitative analysis of flavonoids and other phenolic components was made by a LC-DAD/ESI-MS<jats:sup>n</jats:sup> optimized chromatographic method. A total of 17 phenolic components were identified and classified as: acids (2), procyanidins (2) and flavonoid glycosides (13). The most prevalent components were flavonoid glycosides, especially flavonols and methylated flavonols (9). Additionally, 3 components were found as acylated flavonol glycosides with ferulic and p-coumaric acid. The last one was found not only in esterified form but also in the free form. Only one flavone-apigenin glycoside was detected. Procyanidins were identified as catechin derivatives, both dimers and trimers. </jats:p>
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Phenolic compounds and antioxidant activity of Macedonian red wines
(Elsevier BV, 2015-08)
Ivanova-Petropulos, Violeta
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Hermosín-Gutiérrez, Isidro
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Boros, Borbála
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Stafilov, Trajče
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Chemical characterization of Centaurium erythrea L. and its effects on carbohydrate and lipid metabolism in experimental diabetes
(2014-02-27)
Stefkov, Gjoshe
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Dinevska-Kjovkarovska, Suzana
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Stanoeva, Jasmina Petreska
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Centaurium erythrea L. fam. Gentianaceae (CE) has been traditionally used for centuries in folk medicine of Balkans as a bitter medicinal herb for digestive complications and for treating febrile conditions and diabetes. The aim of this study was to gain insight into the chemical composition and underlying biochemical mechanism of action of the antihyperglycemic and antilipidemic activities of the dry extract of Centaurium erythrea L., wildly growing and traditionally used medicinal plant in the Republic of Macedonia.
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Resource assessment and economic potential of bilberries (Vaccinium myrtillus and Vaccinium uliginosum) on Osogovo Mtn., R. Macedonia
(Elsevier BV, 2014-11)
Stefkov, Gjoshe
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Petreska Stanoeva, Jasmina
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Melovski, Ljupcho

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