Olena vergun

Olena vergun


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 August 2020 in Potravinarstvo Slovak Journal of Food Sciences
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OSOlga V Shelepova
Olga V Shelepova
YVYulia Vinogradova
Yulia Vinogradova
OVOlena vergun
Olena vergun
OGOlga Grygorieva
Olga Grygorieva
JBJán Brindza
Ján Brindza
Solidago canadensis L. was introduced to Europe as an ornamental plant from North America in 1645 and began to spread during the XIX-XX centuries. Nowadays the species is considered the most aggressive invasive species. On the other hand, S. canadensis is considered to be a medicinal plant. The raw material known as Herba Solidaginis includes herbs of S. canadensis, S. gigantea, and S. virgaurea. These species are known for their diuretic, anti-inflammatory, antimicrobial, antioxidant, antispasmodic properties. The purpose of our study was to analyze the chemical compounds and some biological properties of S. canadensis, growing in Slovakia, to evaluate its therapeutic potential. The total phenolic content (TPC) of the extracts from aerial parts of S. canadensis was determined by the Folin-Ciocalteu method. The evaluation of total flavonoid content (TFC) was performed by using a spectrophotometric method. The flavonoids content was expressed as rutin equivalents (mg REs) per g DW vegetal product. The phytochemical profile of S. canadensis extracts was assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The radical scavenging activity of samples was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Reducing power of extracts was determined by the phosphomolybdenum method. Total phenolic contents (TPC) and total flavonoid contents (TFC) of the extracts varied from 204.19 to 293.43 mg GAE.g-1 DW, and 64.99 – 175.25 g QE.g-1 DW, respectively; the best results were obtained for ethanol extract. Some phenolic compounds were identified by HPLC with significant amounts of rutin (211.20 µg.mL-1), quercetin (122.08 µg.mL-1), quercitrin (102.50 µg.mL-1) and chlorogenic acid (147.00 µg.mL-1). The DPPH values in the inflorescences were higher than in the leaves: the antioxidant activity of leaf extracts was in the range from 5.34 to 17.16 mg TE.g-1, for inflorescences, this parameter ranged from 6.09 to 19.87 mg TE.g-1. The high total phenolic compounds and flavonoids can be used as a valuable source of phytochemicals in herbal remedies. Our study of S. canadensis, growing in Slovakia, shows the promising potential that can be evaluated as an effective antioxidant and antimicrobial agent in herbal medicines.

26 January 2019 in Potravinarstvo Slovak Journal of Food Sciences
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OVOlena vergun
Olena vergun
LSLiudmyla Svydenko
Liudmyla Svydenko
OGOlga Grygorieva
Olga Grygorieva
OSOksana Shymanska
Oksana Shymanska
DRDzhamal Rakhmetov
Dzhamal Rakhmetov
EIEva Ivanišová
Eva Ivanišová
The aim of this study was to evaluate antioxidant capacity of Scutellaria baicalensis Georgi from two regions of Ukraine: Kyiv city (M. M. Gryshko National Botanical Garden of NAS of Ukraine (NBG)) and Kherson region (Experimental Facility “Novokakhovska” of Rice Research Institute of Ukrainian Academy of Agrarian Sciences (EFN of RRI)). Observation of plants and biochemical analyses conducted with plants collected in the stage of flowering. In study investigated and compared above-ground part of plants and separated organs: inflorescences, stems, leaves. Measured morphometric parameters (height of plants, length, and width of leaves, length, and diameter of inflorescence, the diameter of the stem) showed that the most variable was the length of inflorescence (12.79%) for NBG sample and diameter of the stem (33.33%) for EFN of RRI sample. Ethanolic extracts were screened for the antioxidant capacity. As standards were used gallic acid for polyphenol content (GAE), quercetin for flavonoids (QE), caffeic acid for phenolic acids (CAE), Trolox for antioxidant capacity (TE). The total content of polyphenol compounds was 42.43 – 86.13 mg GAE.g-1 DW (dry weight) (NBG sample) and 28.06 – 96.76 mg GAE.g-1 DW (EFN of RRI sample). The content of flavonoids was9.39 – 62.97 mg QE.g-1 DW (NBG sample) and 10.64 – 66.07 mg QE.g-1 DW (EFN of RRI sample). The concentration of phenolic acids was 2.60 – 16.13 mg CA.g-1 DW (NBG sample) and 12.02 – 30.12 CA.g-1 DW (EFN of RRI sample). Antioxidant activity of plant extracts was measured by DPPH assay and reducing power method. The first method indicated an antioxidant ability 8.24 – 8.56 mg TE.g-1 DW (NBG sample) and 7.63 – 8.83 mg TE.g-1 DW (EFN of RRI sample). Reducing power of extracts was 51.48 – 306.09 mg TE.g-1 DW (NBG sample) and 63.33 – 260.24 mg TE.g-1 DW (EFN of RRI sample). Very strong positive correlation identified between total polyphenol content, total flavonoid content and reducing power. Scutellaria baicalensis is a rich source of antioxidants and potential raw of further pharmacological study in Ukraine as well as in other regions for improving and enrichment of relevant production.

2 February 2018 in Potravinarstvo Slovak Journal of Food Sciences
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VSVladimíra Horčinová Sedláčková
Vladimíra Horčinová Sedláčková
Olga GrygorievaOlga Grygorieva
Olga Grygorieva
KFKatarí­nA Fatrcová-Šramková
Katarí­nA Fatrcová-Šramková
OVOlena vergun
Olena vergun
YVYulia Vinogradova
Yulia Vinogradova
JBJan Brindza
Jan Brindza
The aim of this study was to determine the basic morphological characteristics (weight, length) and antioxidant activity (using DPPH method) of elderberry (Sambucus nigra L.) inflorescences as well as some elderberry-derived food products prepared from fresh (honey, alcoholic extract, tea infusions) and dried inflorescences (syrup). For the study of problematic, it was used 113 wild-growing genotypes of elderberry from 56 locations in Slovakia growing at an altitude of 98.15 - 712.32 m. The weight of fresh inflorescences ranged from 0.45 to 57.59 g (75.65% coefficient of variation value), the total length of inflorescences ranged from 19.0 to 282.0 mm (22.42%), the length of inflorescence´s stems from 9.0 to 197.0 mm (31.51%), a number of petals predominated pentanumerous petals. Variability in primary and secondary branching reported a low to high degree of variability among as well as within the genotypes. Results showed significant differences in the shape of inflorescences and the colour of flowers among each genotype. Antioxidant activity by DPPH method in elderberry inflorescence water extract was between 85.12 and 89.29%. Activation of tea infusions and beverages was ensured using a mechanism Kalyxx based on galvanic effect. In beverages made from 10% diluted honey prepared from fresh inflorescences in the carbohydrate-based extract, anti-radical activity was determined in the range of 16.81 - 24.16%. In an alcoholic extract from fresh inflorescences, anti-radical activity was between 90.99 and 93.16%. In beverages acquired from the syrup of flowers, we identified antioxidant activity ranging from 37.92 (10%) to 62.82% (40%). Results indicated that elderberry inflorescences and elderberry-derived food products can be attractive to consumers and in future can increase the assortments of healthy products.

22 December 2020 in The Open Agriculture Journal
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SRSvitlana O. Rakhmetova
Svitlana O. Rakhmetova
OVOlena vergun
Olena vergun
RBRostislav Y. Blume
Rostislav Y. Blume
OBOleksandr P. Bondarchuk
Oleksandr P. Bondarchuk
OSOksana V. Shymanska
Oksana V. Shymanska
DRDzhamal B. Rakhmetov
Dzhamal B. Rakhmetov
Background: Sweet sorghum (Sorghum saccharatum (L.) Moench) is a unique crop with great potential to serve both the food and energy industries. It is due to the possibility of (bio)ethanol production both from the juice and biomass of this crop. The sorghum stems juice contains sugar in the levels similar to that of sugarcane. Besides, low cultivation requirements for the sweet sorghum make this crop even more attractive for sugar and ethanol production. In terms of technology, sweet sorghum is seen as a transitional feedstock for the first to the second generation bioethanol production. However, effective technological development of the plant cultivation and processing in the Northern and Central Ukraine is restrained by the lack of a collection of sweet sorghum genotypes and adapted varieties for its large-scale cultivation. Additionally, no evaluations of potential (bio)ethanol productivity have been performed for this region, which is important for efficient implementation of novel biofuel-producing technologies and for successful development of a green economy. Objective: This research was aimed to create a pool of sweet sorghum genotypes with the involvement of worldwide germplasm, analyze their morphology and breed high-yielding plant lines for the efficient production of liquid biofuels for second-generation bioenergy. Based on that, we also aimed to explore the prospects regarding the efficiency of sweet sorghum cultivation for (bio)ethanol production in the Northern and Central Ukraine. Methods and Materials: A valuable gene pool of S. saccharatum (L.) Moench (41 samples) was created; in particular, high-performance genotypes were created for cultivation under the soil-climatic conditions of Ukraine. The bio-morphological features and the yield potential of the plants were determined and the biochemical composition of the phyto-raw materials was determined in different periods of vegetation, in particular, during the technical ripeness of the above-ground mass of plants. The more productive forms and varieties of sugar sorghum in terms of yield, dry matter content, sugar, and energy value of biomass during flowering and waxy ripeness are highlighted. The technological properties of plant biomass for the production of alternative liquid fuels (in particular, bioethanol) have been analyzed. Importantly, optimal cultivation conditions have been elaborated for the newly created sweet sorghum genotypes, and their productivity has also been evaluated. Moreover, for the first time, a detailed study on potential ethanol yield has been conducted. Results: Sweet sorghum has considerable potential in Ukraine as a new sugar-producing energy crop. The germplasm collection of this crop has been created (41 accessions), including introduced and acclimated genotypes and newly bred lines and varieties. The biological performance of sorghum in Ukraine and plant morphology have been analyzed. The most promising genotypes were used for breeding of new high-productive sweet sorghum varieties. The potential (bio)ethanol yield for different sugar feedstocks (juice, grain bagasse) can reach up to 11423 L/ha in total from juice, grain and bagasse. Conclusion: The estimated values of ethanol productivity are comparable to the results of other similar investigations. In conclusion, a high performance of sweet sorghum in Ukraine can be suggested.

28 March 2020 in Potravinarstvo Slovak Journal of Food Sciences
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OVOlena vergun
Olena vergun
OSOksana Shymanska
Oksana Shymanska
DRDzhamal Rakhmetov
Dzhamal Rakhmetov
Olga GrygorievaOlga Grygorieva
Olga Grygorieva
EIEva Ivanišová
Eva Ivanišová
JBJan Brindza
Jan Brindza
The plant raw material of Galega officinalis L. (goat’s rue) and Galega orientalis Lam. (fodder galega) investigated in this study. These species are known as fodder crops with high productivity of green mass and as medicine plants. The current study was aimed to evaluate an accumulation in dry raw of selected plants the total content of phenolic acids (TPA) and flavonoids (TFC) as compounds with antioxidant activity (AA) by spectrophotometric method. AA by DPPH-method and phosphomolybdenum method (reducing power (RP)) was measured. Study of ethanolic extracts of G. officinalis showed accumulation of TPA in different organs in range from 3.65 to 15.17 mg.g-1 caffeic acid equivalent (CAE) and TFC from 10.08 to 65.75 mg.g-1 quercetin equivalent (QE), AA by DPPH-method from 6.02 to 8.45 mg.g-1 Trolox equivalent (TE) and RP of extracts by phosphomolybdenum method from 86.56 to 288.15 mg TE.g-1. In extracts of G. orientalis was identified TPA from 3.52 to 18.52 mg CAE.g-1 and TFC from 6.09 to 46.72 mg QE.g-1, antioxidant activity by DPPH-method from 6.80 to 8.48 mg TE.g-1 and antioxidant capacity by phosphomolybdenum method from 52.52 to 188.51 mg TE.g-1. It was established that less concentration of studied compounds found in the stems for both species. It should be noted that the content of phenolic acids in the leaves was decreased and flavonoids in stems increased during vegetation for both species. Content of phenolic acids in the generative organs and flavonoids in the leaves decreased in raw of G. orientalis during vegetation. Pearson’s correlation analysis demonstrated very strong relations between TFC and AA by DPPH, TPA and RP, TFC and RP for G. officinalis extracts. Very strong correlation in the extracts of G. orientalis found between TFC and RP, TPA and RP. Obtained results can be used in the further biochemical and pharmacological study.

26 January 2019 in Potravinarstvo Slovak Journal of Food Sciences
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JBJan Brindza
Jan Brindza
Olga GrygorievaOlga Grygorieva
Olga Grygorieva
SKSvitlana Klymenko
Svitlana Klymenko
OVOlena vergun
Olena vergun
JMJán Mareček
Ján Mareček
EIEva Ivanišová
Eva Ivanišová
The objective of this study was to evaluate the morphological parameters and bioactive compounds (antioxidant activity, total polyphenol, flavonoid, and phenolic acid content) of 6 genotypes of dry Asimina triloba (L.) fruit from Slovak University of Agriculture in Nitra (Slovakia). Genotypes were obtained from the seeds that were sown in the year 2000. Their morphometric parameters were following: fruit weight from 59.00 to 241.19 g, fruit length from 50.14 to 140.11 mm, fruit diameter from 37.55 to 64.67 mm, number of fruits per cluster from 2 to 8, seed weight from 0.06 to 1.80 g, seed length from 16.33 to 29.11 mm, seed width from 9.56 to 18.33 mm, seed thickness from 4.98 to 9.75 mm, number of seeds in fruit from 4 to 16. The shape indexes of fruits were found ranging from 1.53 to 2.16. The variability of important is the average seeds weight from 7.40 to 35.61%, fruit weight from 14.84 to 32.95%, number of fruits per cluster from 18.21 to 32.54% and a number of seeds in fruit from 13.49 to 27.72%. The other characteristics are more or less stable. Total polyphenol content ranged from 22.13 to 37.36 mg GAE per g, total flavonoid content from 15.10 to 32.03 mg QE per g and phenolic acids content from 0.23 to 0.76 mg CAE per g. All tested samples exhibited DPPH radical scavenging activities with values from 2.84 to 7.04 mg TEAC per g. Antioxidant activity by molybdenum reducing antioxidant power method ranged from 97.25 to 275.41 mg TEAC per g of dry matter. Differences between the genotypes were significant in all observed parameters. This species is potential for propagation and practice used in the Slovak Republic.