Effect of Salinity Stress on Phenolic Compounds and Antioxidant Activity in Halophytes Spergularia marina (L.) Griseb. and Glaux maritima L. Cultured In Vitro.

The study of halophytes as sources of phenolic compounds, as well as conditions that further enhance the accumulation of biologically active compounds in them, is of particular interest. In this paper, the effect of different salinity levels (25-500 mM in the form of NaCl) on the content of phenolic compounds and the antioxidant activity of two rare halophyte species Spergularia marina (L.) Griseb. and Glaux maritima L. cultured in vitro was investigated. A species-specific reaction of plants to salinization was established. In G. maritima, the maximum total content of phenolic compounds was observed at 50-100 mM, flavonoids 75-400 mM, and hydroxycinnamic acids 200-300 mM, as well as individual phenolics (protocatechuic acid, catechin, astragalin, hyperoside, rutin, isoquercitrin, and apigenin derivative) at 100-300 mM NaCl. For S. marina, on the contrary, there was a slight decrease in the content of phenolic compounds when NaCl was added to the nutrient medium compared to the control. The content of protocatechuic acid, rosmarinic acid, and apigenin derivative significantly decreased with increased salt stress. The change in antioxidant activity at different salinity levels was also species specific. The maximum values of different groups of phenolic compounds in G. maritima were observed at 50-300 mM NaCl. The cultivation of S. marina without the addition of NaCl and at 500 mM NaCl allowed the production of plants with the highest content of phenolic compounds. The obtained results can be further used in the development of protocols for the cultivation of these plants in vitro in order to induce the biosynthesis of phenolic compounds in them.

Variation in Phenolic Compounds, Antioxidant and Antibacterial Activities of Extracts from Different Plant Organs of Meadowsweet (Filipendula ulmaria (L.) Maxim.).

Meadowsweet (Filipendula ulmaria (L.) Maxim.) has been widely used in the treatment of various diseases. The pharmacological properties of meadowsweet are derived from the presence of phenolic compounds of a diverse structure in sufficiently large quantities. The purpose of this study was to examine the vertical distribution of individual groups of phenolic compounds (total phenolics, flavonoids, hydroxycinnamic acids, catechins, proanthocyanidins, and tannins) and individual phenolic compounds in meadowsweet and to determine the antioxidant and antibacterial activity of extracts from various meadowsweet organs. It was found that the leaves, flowers, fruits, and roots of meadowsweet are characterized by a high total phenolics content (up to 65 mg g-1). A high content of flavonoids was determined in the upper leaves and flowers (117-167 mg g-1), with high contents of hydroxycinnamic acids in the upper leaves, flowers, and fruits (6.4-7.8 mg g-1); high contents of catechins and proanthocyanidins in the roots (45.1 and 3.4 mg g-1, respectively); and high tannin content in the fruits (38.3 mg g-1). Analysis of extracts by high-performance liquid chromatography (HPLC) showed that the qualitative and quantitative composition of individual phenolic compounds in various parts of the meadowsweet varied greatly. Among the flavonoids identified in meadowsweet, quercetin derivatives dominate, namely quercetin 3-O-rutinoside, quercetin 3-ß-d-glucoside, and quercetin 4'-O-glucoside. Quercetin 4'-O-glucoside (spiraeoside) was found only in the flowers and fruits. Catechin was identified in the leaves and roots of meadowsweet. The distribution of phenolic acids across the plant was also uneven. In the upper leaves, a higher content of chlorogenic acid was determined, and in the lower leaves, a higher content of ellagic acid determined. In flowers and fruits, a higher contents of gallic, caftaric, ellagic, and salicylic acids were noted. Ellagic and salicylic acids were also dominant among phenolic acids in the roots. Based on the results of the analysis of antioxidant activity in terms of the ability to utilize the radicals of 2,2-diphenyl-1-picrylhydrazine (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazolino-6-sulfonic acid) (ABTS) and in terms of iron-reducing ability (FRAP), the upper leaves, flowers, and fruits of meadowsweet can be considered plant raw materials suitable to obtain extracts with high antioxidant activity. Extracts of plant fruits and flowers also showed high antibacterial activity against the bacteria Bacillus subtilis and Pseudomonas aeruginosa.

Effect of Sodium Selenate and Selenocystine on Savoy Cabbage Yield, Morphological and Biochemical Characteristics under Chlorella Supply.

Biofortification of Brassica oleracea with selenium (Se) is highly valuable both for human Se status optimization and functional food production with direct anti-carcinogenic activity. To assess the effects of organic and inorganic Se supply for biofortifying Brassica representatives, foliar applications of sodium selenate and selenocystine (SeCys2) were performed on Savoy cabbage treated with the growth stimulator microalgae Chlorella. Compared to sodium selenate, SeCys2 exerted a stronger growth stimulation of heads (1.3 against 1.14 times) and an increase of leaf concentration of chlorophyll (1.56 against 1.2 times) and ascorbic acid (1.37 against 1.27 times). Head density was reduced by 1.22 times by foliar application of sodium selenate and by 1.58 times by SeCys2. Despite the greater growth stimulation effect of SeCys2, its application resulted in lower biofortification levels (2.9 times) compared to sodium selenate (11.6 times). Se concentration decreased according to the following sequence: leaves > roots > head. The antioxidant activity (AOA) was higher in water extracts compared to the ethanol ones in the heads, but the opposite trend was recorded in the leaves. Chlorella supply significantly increased the efficiency of biofortification with sodium selenate (by 1.57 times) but had no effect in the case of SeCys2 application. Positive correlations were found between leaf and head weight (r = 0.621); head weight and Se content under selenate supply (r = 0.897-0.954); leaf ascorbic acid and total yield (r = 0.559), and chlorophyll (r = +0.83-0.89). Significant varietal differences were recorded for all the parameters examined. The broad comparison performed between the effects of selenate and SeCys2 showed significant genetic differences as well as important peculiarities connected with the Se chemical form and its complex interaction with Chlorella treatment.

The Integral Boosting Effect of Selenium on the Secondary Metabolism of Higher Plants.

Selenium is a micronutrient with a wide range of functions in animals, including humans, and in microorganisms such as microalgae. However, its role in plant metabolism remains ambiguous. Recent studies of Se supplementation showed that not only does it increase the content of the element itself, but also affects the accumulation of secondary metabolites in plants. The purpose of this review is to analyze and summarize the available data on the place of selenium in the secondary metabolism of plants and its effect on the accumulation of some plant metabolites (S- and N-containing secondary metabolites, terpenes, and phenolic compounds). In addition, possible molecular mechanisms and metabolic pathways underlying these effects are discussed. It should be noted that available data on the effect of Se on the accumulation of secondary metabolites are inconsistent and contradictory. According to some studies, selenium has a positive effect on the accumulation of certain metabolites, while other similar studies show a negative effect or no effect at all. The following aspects were identified as possible ways of regulating plant secondary metabolism by Se-supplementation: changes occurring in primary S/N metabolism, hormonal regulation, redox metabolism, as well as at the transcriptomic level of secondary metabolite biosynthesis. In all likelihood, the confusion in the results can be explained by other, more complex regulatory mechanisms in which selenium is involved and which affect the production of metabolites. Further study on the involvement of various forms of selenium in metabolic and signaling pathways is crucial for a deeper understanding of its role in growth, development, and health of plants, as well as the regulatory mechanisms behind them.

Biotechnological Potential of Different Organs of Mistletoe (Viscum album L.) Collected from Various Host Tree Species in an Urban Area.

From an economic and ecological standpoint, it is crucial to investigate the biologically active compounds of mistletoe plants, which are currently discarded by pruning urban mistletoe-infested trees. In the present study, the content of phenolic compounds, triterpenic and organic acids, as well as the antioxidant activity of the extracts of various mistletoe organs (leaves, stems, and fruits) collected from the most infested tree species were investigated. The mistletoe samples collected from Betula pendula, Acer platanoides, Crataegus monogyna, and Sorbus aucuparia showed the highest content of phenolic acids and flavonoids as well as antioxidant activity, as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing/antioxidant power (FRAP) assays. The leaves and stems of mistletoe from Tilia cordata were characterized by a high content of triterpenic acids (oleanolic, ursolic, and betulinic). The leaves and fruits of mistletoe plants from Populus nigra and Salix alba contained a high concentration of organic acids, particularly succinic and citric acids. Compared to stem and leaf extracts, the antioxidant activity of the mistletoe fruit extracts was 1.5-3 times higher. The obtained results indicate that mistletoe is a valuable raw material and can be used as a source of phenolic compounds and triterpenic and organic acids, as well as for producing extracts with antioxidant properties.

Study of the Antioxidant Properties of Filipendula ulmaria and Alnus glutinosa.

The demographic situation of the last few decades is characterized by the increased numbers of elderly and senile people, i.e., by the aging of the population. In humans, ageing is closely associated with the enhanced production of reactive oxygen species (ROS), development of systemic inflammation and related vascular atherosclerotic alterations and metabolic disorders, like obesity, diabetes mellitus and neurodegenerative diseases. As these age-related alterations are directly associated with up-regulation of ROS production and development of chronic oxidative stress, their onset can be essentially delayed by continuous daily consumption of dietary antioxidants-natural products of plant origin. Such antioxidants (in the form of plant extracts, biologically active complexes or individual compounds) can be supplemented to functional foods, i.e., dietary supplementations for daily diet aiming prolongation of active life and delay of the senescence onset. Thereby, use of widely spread medicinal plants might essentially improve cost efficiency of this strategy and availability of antioxidant-rich functional foods. Therefore, here we addressed, to the best of our knowledge for the first time, the antioxidant activity of the extracts prepared from the aerial parts of Filipendula ulmaria and Alnus glutinosa growing in the Kaliningrad region of Russia, and assessed the contents of the biologically active substances underlying these properties. It was found that the extract prepared with the leaves of Filipendula ulmaria and female catkins of Alnus glutinosa demonstrated high antioxidant activity, although the former plant was featured with a higher antioxidant potential. The highest antioxidant activity detected in the methanol extracts of Alnus glutinosa reached 1094.02 ± 14.53 µmol TE/g, radical scavenging of activity was 584.45 ± 35.3 µmol TE/g, reducing capacity at interaction with iron complex-471.63 ± 7.06 µmol TE/g. For the methanol extracts of Filipendula ulmaria the antioxidant activity reached 759.78 ± 19.08 µmol TE/g, antioxidant activity for free radical removal was 451.08 ± 24.45 µmol TE/g and antioxidant activity for restorative ability with iron complex was 332.28 ± 10.93 µmol TE/g. These values are consistent with the total yields of the extracts and their content of ellagic acid. The ethyl acetate extracts of the both plants showed just minimal antioxidant activity. Thus, the considered extracts have an essential potential. This creates good prospects for the further use of herbal extracts of Filipendula ulmaria and Alnus glutinosa as a source of natural antioxidants.

Effect of salicylic acid on phenolic compounds, antioxidant and antihyperglycemic activity of Lamiaceae plants grown in a temperate climate.

BACKGROUND: The Lamiaceae family, one of the most important herbaceous and shrub plant families, includes a wide variety of plants with biological and medicinal uses. This study aimed to conduct a comparative analysis of phenolic compounds content and biological activity of extracts from eight species of Lamiaceae plants, cultivated in a temperate climate, and to study the effect of the foliar salicylic acid application on these parameters. METHODS: Lamiaceae plants (Lavandula angustifolia, Salvia officinalis, Hyssopus officinalis, Agastache foeniculum, Thymus serpyllum, Mentha × piperita, Origanum vulgare, Monarda didyma) cultivated on field experimental sites. Plants were sprayed with salicylic acid at a concentration of 1 mM. The untreated with salicylic acid plants were used as control. RESULTS: The highest contents of hydroxycinnamic acids and flavonoids in control plants were observed in the Agastache foeniculum (6.4 ± 0.6 mg g-1 and 6.5 ± 0.4 mg g-1 respectively). The highest content of phenolic compounds was found in Monarda didyma (13.8 ± 0.7 mg g-1). Among the control plants, Agastache foeniculum, Hyssopus officinalis, and Mentha × piperita were characterized by the highest antioxidant activity. All the studied extracts had the ability to inhibit α-amylase and α-glucosidase. Significant positive correlations were revealed between the antioxidant activity and the contents of hydroxycinnamic acids, total phenolic compounds, and flavonoids. A high degree of correlation was found between the α-amylase inhibitory activity and the content of hydroxycinnamic acids (r = 0.72, p ≤ 0.05), as well as between the α-glucosidase inhibitory activity and the content of flavonoids (r = 0.83, p ≤ 0.05) and hydroxycinnamic acids (r = 0.81, p ≤ 0.05). The foliar treatment with salicylic acid led to an increase in the contents of hydroxycinnamic acids (in 6 species), flavonoids (in 2 species), total phenolic compounds (in 7 species), antioxidant activity (in 5 species), as well as in α-amylase (in 4 species) and α-glucosidase (in 5 species) inhibitory activity compared to the control plants. Lavandula angustifolia was the most susceptible to foliar treatment with salicylic acid. In this plant species, a significant increase in all studied biochemical parameters was noted. CONCLUSIONS: The results obtained on the stimulating effects of salicylic acid can be used to increase the nutritional and pharmacological value of plants of the Lamiaceae family cultivated in temperate climates.

Variability of Phenolic Compound Accumulation and Antioxidant Activity in Wild Plants of Some Rumex Species (Polygonaceae).

Today, more than ever, the search for non-trivial sources of biologically active substances is critical. Plants of the genus Rumex are noteworthy. Plants of this genus stand out for a number of advantages from the dominant plant core of meadow phytocenoses of the temperate climatic zone: a short growing season, an intensive increase in biomass, and undemanding growth conditions. In addition, this plant genus is known as a super-producer of secondary phenolic compounds. The wide distribution and intensive synthesis of biologically active substances make plants from the genus Rumex a promising object for study. Seven species of the genus Rumex (R. acetosa, R. acetosella, R. confertus, R. crispus, R. maritimus, R.obtusifolius, and R. sanguineus) were analyzed. Plants were collected under relatively uniform growing conditions. For subsequent extraction and analysis of phenolic compounds, as well as antioxidant activity, plants leaves were used. R. acetosella, R. crispus, R. maritimus, R. obtusifolius, and R. sanguineus were characterized by a high total content of phenolic compounds (111-131 mg g-1). The maximum content of flavonoids was found in the leaves of R. maritimus and R. acetosella. At the same time, according to high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis, derivatives of flavones (apigenin and luteolin) predominated in the leaves of R. acetosella, while in other species, mainly derivatives of flavonols (quercetin and kaempferol) were identified. Plants of R. acetosa, in comparison with other studied species, were characterized by a lower content of the studied groups of phenolic compounds, with the exception of hydroxycinnamic acids, the content of which in this species was comparable to the content of flavonoids. The maximum content of catechins was found in R. sanguineus; proanthocyanidins-in R. sanguineus, R. obtusifolius, and R. crispus; and tannins-in R. obtusifolius. Extracts from R. crispus were characterized by high antioxidant activity, measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) assays. In addition, the assessment of the phenolic profile of the plant made it possible to group the plants within the framework of cluster analysis. The distribution pattern in the clusters corresponded to the generally accepted taxonomy, with a characteristic division into subgenera (Acetosa, Acetosella, and Rumex). Thus, the phenolic profile can be considered as an additional instrumental approach when drawing up a systematic hierarchy.

Effect of Selenium Application and Growth Stage at Harvest on Hydrophilic and Lipophilic Antioxidants in Lamb's Lettuce (Valerianella locusta L. Laterr.).

Lamb's lettuce (Valerianella locusta L. Laterr.) is a leafy green vegetable that is rich in various biological active compounds and is widely used in ready-to-eat salads. The cultivation conditions and growth stage could affect the secondary metabolism in plants and thereby modify their food value. In the present study, the effect of selenium (Se) application in various concentrations (5.0, 10.0, and 20.0 µM) on the contents of Se, phenolic compounds, vitamin C, carotenoids, chlorophylls, and antioxidant activity of hydrophilic and lipophilic extracts of lamb's lettuce harvested at three growth stages (38, 52, and 66 days after sowing (DAS)) was studied. Se application significantly increased the Se concentration in the shoots (up to 124.4 µg g-1 dry weight), as well as the contents of chlorogenic acid, total flavonoids, total phenolics, ascorbic acid, chlorophyll b, and the antioxidant activity of hydrophilic and lipophilic extracts. A higher content of phenolic compounds and higher antioxidant activity of hydrophilic extracts was observed at the first growth stage (38 DAS). On the contrary, higher contents of lipophilic compounds (chlorophyll a, chlorophyll b, lutein, ß-carotene) and higher antioxidant activity of lipophilic extracts were found for shoots harvested at later stages (52 and 66 DAS).

Chemical Composition and Content of Biologically Active Substances Found in Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha Growing in Various Territories.

Medicinal plants (Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha) growing in various territories (Kaliningrad, Moscow, and Minsk regions) were the objects of research. This paper presents a study of the chemical composition of these plants. To analyze the qualitative and quantitative composition of biologically active substances, the method of high-performance liquid chromatography was used. Atomic absorption spectrometry was used to study the content of trace elements. The content of organic acids and vitamins was determined by capillary electrophoresis using the Kapel-105/105M capillary electrophoresis system with high negative polarity. Extracts of medicinal plants were obtained on a Soxhlet apparatus using 70% ethanol as an extractant. It was found that among the biologically active substances in the plants under discussion, hyperoside, rutin (C. coggygria), Ferulic acid and Gallic acid (D. maculata), triene hydrocarbon (3,7-Dimethyl-1,3,6-octatriene), unsaturated alcohol (3,7-Dimethyl-2,6-octadien-1-ol), and benzyl acetate (P. chlorantha) prevailed. Samples of these medicinal plants contained trace elements (phosphorus, potassium, calcium, sodium, magnesium, and sulfur) and many aliphatic organic acids (succinic acid, benzoic acid, fumaric acid, citric acid, oxalic acid, and tartaric acid). The largest amount of biologically active substances and secondary metabolites of the studied plants from the Eastern Baltic is associated with climatic and ecological differences from other regions. The composition of these plants determines the potential of their use in feed additives for livestock and poultry as part of measures to improve the quality of livestock products. The use of medicinal plants for the production of feed additives is relevant in terms of improving regional economies, as well as improving the quality of life and nation's health by providing ecologically clean livestock products.

Assessment of the Role of PAL in Lignin Accumulation in Wheat (Tríticum aestívum L.) at the Early Stage of Ontogenesis.

The current study evaluates the role of phenylalanine ammonia-lyase (PAL) and the associated metabolic complex in the accumulation of lignin in common wheat plants (Tríticum aestívum L.) at the early stages of ontogenesis. The data analysis was performed using plant samples that had reached Phases 4 and 5 on the Feekes scale-these phases are characterized by a transition to the formation of axial (stem) structures in cereal plants. We have shown that the substrate stimulation of PAL with key substrates, such as L-phenylalanine and L-tyrosine, leads to a significant increase in lignin by an average of 20% in experimental plants compared to control plants. In addition, the presence of these compounds in the nutrient medium led to an increase in the number of gene transcripts associated with lignin synthesis (PAL6, C4H1, 4CL1, C3H1). Inhibition was the main tool of the study. Potential competitive inhibitors of PAL were used: the optical isomer of L-phenylalanine-D-phenylalanine-and the hydroxylamine equivalent of phenylalanine-O-Benzylhydroxylamine. As a result, plants incubated on a medium supplemented with O-Benzylhydroxylamine were characterized by reduced PAL activity (almost one third). The lignin content of the cell wall in plants treated with O-Benzylhydroxylamine was almost halved. In contrast, D-phenylalanine did not lead to significant changes in the lignin-associated metabolic complex, and its effect was similar to that of specific substrates.

Changes in Antioxidative Compounds and Enzymes in Small-Leaved Linden (Tilia cordata Mill.) in Response to Mistletoe (Viscum album L.) Infestation.

Mistletoe infestation leads to a decrease in the growth of woody plants, their longevity, and partial or complete drying of the top, as well as premature death. Various environmental stress factors, both abiotic and biotic, stimulate the formation of reactive oxygen species and the development of oxidative stress in plant tissues. This study aimed to investigate the effect of mistletoe (Viscum album L.) infestation on the response of the antioxidative defense system in leaves of small-leaved linden (Tilia cordata Mill.). Leaves from infested trees were taken from branches (i) without mistletoe, (ii) with 1-2 mistletoe bushes (low degree of infestation), and (iii) with 5-7 mistletoe bushes (high degree of infestation). The relative water content and the chlorophyll a and b contents in leaves from linden branches affected by mistletoe were significantly lower than those in leaves from non-infested trees and from host-tree branches with no mistletoe. At the same time, leaves from branches with low and high degrees of infestation had significantly higher electrolyte leakage, malondialdehyde and hydrogen peroxide content, oxidized forms of ascorbic acid (dehydroascorbic and 2,3-diketogulonic acids), and oxidized glutathione. The results of principal component analysis show that the development of oxidative stress was accompanied by an increase in proline content and in superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, and glutathione reductase activity. Several biochemical parameters (proline, ascorbic acid, dehydroascorbic acid, glutathione, glutathione peroxidase, ascorbate peroxidase, and dehydroascorbate reductase) were found to be altered in leaves from host-tree branches with no mistletoe. This result indicates that the mistletoe infestation of trees not only causes local changes in the locations of hemiparasite attachment, but also affects the redox metabolism in leaves from other parts of the infested tree.

A Study of the Antioxidant, Cytotoxic Activity and Adsorption Properties of Karelian Shungite by Physicochemical Methods.

This study reveals that fossil shungite samples exhibit antioxidant activity, can reduce oxidized components, and bind to free radicals. A sample of Sh20 (size fraction-20 µm) (1.30 mg equivalents of ascorbic acid/g of shungite; 3.46 mg equivalents of trolox/g of shungite; 0.99 mg equivalents of quercetin/g of shungite) had the maximal activity according to the amperometric method. The obtained data indicate that shungite has antioxidant properties, but these are approximately 1000 times less pronounced than those of quercetin. A ShT20 sample (size fraction-20 µm + heat treatment) was found to have the highest antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl radical and cytotoxicity. Further studies, including the optimization of the antioxidant extraction conditions of shungite, and the analysis of the qualitative and quantitative composition of the obtained extracts, are required for a more accurate interpretation of the results. Shungite can be applied as an alternative to activated carbon in water purification, due to its absorption, catalytic, antioxidant, regenerating, and antibacterial properties, as well as its high environmental safety and relatively low cost. It is possible to identify new structural forms of carbon within, and other valuable properties of, shungite substance, which will make it possible to create effective technologies for the practical use of shungite rocks, particularly in the production of fullerenes and other carbon nanoclusters.

Joint Biofortification of Plants with Selenium and Iodine: New Field of Discoveries.

The essentiality of selenium (Se) and iodine (I) to human beings and the widespread areas of selenium and iodine deficiency determine the high significance of functional food production with high levels of these elements. In this respect, joint biofortification of agricultural crops with Se and I is especially attractive. Nevertheless, in practice this topic has raised many problems connected with the possible utilization of many Se and I chemical forms, different doses and biofortification methods, and the existence of wide species and varietal differences. The limited reports relevant to this subject and the multiplicity of unsolved questions urge the need for an adequate evaluation of the results obtained up-to-date, useful for developing further future investigations. The present review discusses the outcome of joint plant Se-I biofortification, as well as factors affecting Se and I accumulation in plants, paying special attention to unsolved issues. A particular focus has been given to the prospects of herb sprouts production enriched with Se and I, as well as the interactions between the latter microelements and arbuscular-mycorrhizal fungi (AMF).

Study of the Biologically Active Properties of Medicinal Plant Cotinus coggygria.

The results of the studies have shown that to obtain an extract of a complex of biologically active substances of Cotinus coggygria, ethyl alcohol (mass fraction of alcohol 70%) with a hydromodule of 1:5 should be used, and the extraction should be carried out for 60 min at a temperature of 60 °C. The investigated plant extracts with the complex of bioactive substances from the Cotinus coggygria leaves and flowers are safe from the point of view of the content of heavy metals, pesticides, aflatoxin B1, radionuclides, as well as pathogenic and opportunistic microorganisms. It has been established that the Cotinus coggygria extract contains rutin, hyperoside, ferulic acid, quercetin, kaempferol, disulphuretin, sulphurein, sulphurein, gallic acid, methyl gallate, pentagalloyl glucose, 3,3',4',5,6,7-hexahydroxyflavonone, 3,3',4',5,5',7-hexahydroxyflavonone, 3-O-α-L-rhamnofuranoside, 3,3',4',5,5',7-hexahydroxyflavulium(1+), 7-O-ß-D glucopyranoside, and 3,3',4',7-tetrahydroxyflavonone. The tested extracts have anticancer, antigenotoxic, and antimicrobial (against E. coli, S. aureus, P. vulgaris, C. albicans, L. mesenteroides) properties. The high antioxidant status of the tested extracts was established; the antioxidant activity of the samples was 145.09 mg AA/g (AA-ascorbic acid).

Study of the Properties of In Vitro Dactylorhiza maculata (L.) Soó (Family Orchidaceae) Extracts.

The medicinal plant Dactylorhiza maculata (L.) Soó (family Orchidaceae) is used to treat gastritis, colic, gastrointestinal tract, and bladder diseases. This study aimed to investigate the properties and characteristics of the in vitro Dactylorhiza maculata extract. The recommended parameters for producing Dactylorhiza maculata extract were determined: temperature 60 °C, process duration 60 min, hydro module 1:10. It is recommended to carry out the extraction using an aqueous ethyl alcohol solution with a mass fraction of the parent substance of 70%. It was found that such biologically active substances as rutin, quercetin, 3,3',4',5,5',7-hexahydroxyflavonone, 3,3',4',5,5',7-hexahydroxyflavonone-3-O-glycoside, gallic acid, and ferulic acid were dominant in Dactylorhiza maculata. A high phosphorus content was noted (2410.8 mg/kg dry matter). The studied Dactylorhizamaculata samples contained a large number of organic acids and water-soluble vitamins. The tested extracts were safe in terms of the content of heavy metals, pesticides, aflatoxin B1, and radionuclides, as well as pathogenic and opportunistic microorganisms; the content was significantly lower than the threshold limit values. The studied complex of biologically active substances from Dactylorhiza maculata extract samples had antimicrobial properties. It was found that the antioxidant activity of the samples was 217.89 ± 10.89 mg AA/g (AA-ascorbic acid). The high content of bioactive substances and the antimicrobial and antioxidant properties of Dactylorhizamaculata extract samples determine the application potential of this plant as a substitute for growth stimulants and feed antibiotics in the production of feed additives, aiming to increase the physiological and immune status of livestock and poultry.

Effect of Crude Oil on Growth, Oxidative Stress and Response of Antioxidative System of Two Rye (Secale cereale L.) Varieties.

Rye (Secale cereale L.) is one of the most important cereal crops in Eastern and Northern Europe, showing better tolerance to environmental stress factors compared to wheat and triticale. Plant response to the crude oil-polluted soil depends on plant species, oil concentration, time of exposure, etc. The current study is aimed at investigating the growth, oxidative stress and the response of antioxidative system of two rye varieties (Krona and Valdai) cultivated on crude oil-contaminated soils at different concentrations (1.5, 3.0, 6.0, and 12.0%). Inhibition of rye growth was observed at crude oil concentrations of above 3% for above-ground plant parts and of above 1.5% for roots. A decrease in content of chlorophyll a and total chlorophylls in Krona variety was detected at 1.5% oil concentration in soil and in Valdai variety at 3% oil concentration. Compared with the control, the content of malondialdehyde was significantly increased in the Krona variety at 3% oil concentration and in Valdai variety at 6% oil concentration. The crude oil-induced oxidative stress was minimized in rye plants by the enhanced contents of low-molecular antioxidants (proline, non-protein thiols, ascorbic acid, phenolic compounds) and activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The strongest positive correlation was detected between the content of malondialdehyde and contents of proline (r = 0.89-0.95, p ≤ 0.05) and phenolic compounds (r = 0.90-0.94, p ≤ 0.05) as well as superoxide dismutase activity (r = 0.81-0.90, p ≤ 0.05). Based on the results of a comprehensive analysis of growth and biochemical parameters and of the cluster analysis, Valdai variety proved to be more resistant to oil pollution. Due to this, Valdai variety is considered to be a promising rye variety for cultivation on moderately oil-polluted soils in order to decontaminate them. At the same time, it is necessary to conduct further studies aimed at investigating oil transformation processes in the soil-rye system, which would make it possible to determine the efficiency of using this cereal for soil remediation.

Changes in the Content of Some Groups of Phenolic Compounds and Biological Activity of Extracts of Various Parts of Heather (Calluna vulgaris (L.) Hull) at Different Growth Stages.

Heather (Calluna vulgaris (L.) Hull.) is noted for a diverse chemical composition and a broad range of biological activity. The current study was aimed at monitoring changes in the accumulation of certain groups of phenolic compounds in various organs of heather (leaves, stems, roots, rhizomes, flowers, and seeds) at different growth stages (vegetative, floral budding, flowering, and seed ripening) as well as studying antioxidant (employing the DPPH and FRAP assays) and antibacterial activity of its extracts. The highest total amount of phenolic compounds, tannins, flavonoids, hydroxycinnamic acids, and proanthocyanidins was detected in leaves and roots at all growth stages, except for the flowering stage. At the flowering stage, the highest content of some groups of phenolic compounds (flavonoids, proanthocyanidins, and anthocyanins) was observed in flowers. Highest antioxidant activity was recorded for the flower extracts (about 500 mg of ascorbic acid equivalents per gram according to the DPPH assay) and for the leaf extract at the ripening stage (about 350 mg of ascorbic acid equivalents per gram according to the FRAP assay). Strong correlation was noted between antioxidant activity (DPPH) and the content of anthocyanins (r = 0.75, p ≤ 0.01) as well as between antioxidant activity (FRAP) and the total content of phenolic compounds (r = 0.77, p ≤ 0.01). Leaf extracts and stem extracts turned out to perform antibacterial action against both gram-negative and gram-positive bacteria, whereas root extracts appeared to be active only against B. subtilis, and rhizome extracts against E. coli.

Phenylalanine and Tyrosine as Exogenous Precursors of Wheat (Triticum aestivum L.) Secondary Metabolism through PAL-Associated Pathways.

Reacting to environmental exposure, most higher plants activate secondary metabolic pathways, such as the metabolism of phenylpropanoids. This pathway results in the formation of lignin, one of the most important polymers of the plant cell, as well as a wide range of phenolic secondary metabolites. Aromatic amino acids, such as phenylalanine and tyrosine, largely stimulate this process, determining two ways of lignification in plant tissues, varying in their efficiency. The current study analyzed the effect of phenylalanine and tyrosine, involved in plant metabolism through the phenylalanine ammonia-lyase (PAL) pathway, on the synthesis and accumulation of phenolic compounds, as well as lignin by means of the expression of a number of genes responsible for its biosynthesis, based on the example of common wheat (Triticum aestivum L.).

Ecological and Landscape Factors Affecting the Spread of European Mistletoe (Viscum album L.) in Urban Areas (A Case Study of the Kaliningrad City, Russia).

Green spaces are very important for an urban environment. Trees in cities develop under more stressful conditions and are, therefore, more susceptible to parasite including mistletoe infestation. The aim of this study was to investigate the ecological, microclimatic, and landscape factors causing the spread of European mistletoe (Viscum album L.) in urban conditions. The most numerous hosts of mistletoe were Tilia cordata (24.4%), Acer platanoides (22.7%), and Populus nigra (16.7%). On average, there were more than 10 mistletoe bushes per tree. The mass mistletoe infestations (more than 50 bushes per the tree) were detected for Populus × berolinensis, Populus nigra, and Acer saccharinum. The largest number of infected trees was detected in the green zone (city parks), historical housing estates, and green zone along water bodies. Based on the results of principal component analysis (PCA), the main factors causing the spread of mistletoe on the urban territories are trees' age and relative air humidity. The factors reflecting environmental pollution (the content of heavy metals in the soil and the concentration of nitrogen dioxide in the air) did not statistically affect the mistletoe distribution in the study area. However, this result may be due to the heterogeneity of other parameters in the studied areas. Therefore, additional research is required to more accurately interpret the data on the relationship between environmental pollutions and distribution of mistletoe infestation of trees in urban areas.