Plant Phenolic Compounds Research Articles

Unraveling the metabolic activities of bioactive compounds on cellular models of hepatosteatosis and adipogenesis through docking analysis with PPARs

Obesity is associated with fatty liver disease. Available therapies show modest efficacy, and nutraceuticals with good effectiveness and safety are largely investigated. We focused on five natural compounds, three plant phenolic compounds (carvacrol, rosmarinic acid, silybin), and two thyroid hormones (T2: 3,5-diiodo-l-thyronine; T3: 3,5,3’-triiodo-L-thyronine) as comparison, to assess their beneficial effects on two cellular models of hepatosteatosis and adipogenesis. All compounds ameliorated the lipid accumulation and oxidative stress in both models, but with different potencies. The peroxisome proliferator-activated receptors (PPARs) are pivotal controllers of adipogenesis and lipid metabolism. For the main isoforms, PPARγ and PPARa, we assessed their possible binding to the compounds by molecular docking calculations, and their expression pattern by real-time PCR. All compounds bind both PPARs with different affinity, while not all compounds affect their expression. The results may clarify the distinctive molecular mechanisms underlying the action of the five compounds in the different cell models with possible applications to treat obesity.

Comparison of genotoxic impurities in extracted nicotine vs. synthetic nicotine.

Nicotine is a chiral alkaloid; nitrogen-containing organic compound that occurs naturally. (S)-nicotine is extracted from Tobacco plants and used as the key addictive ingredient in many smoking products. Synthetic nicotine has gained the interest of many smoking product manufacturers over the last few decades due to the ease and low cost of manufacturing. Another claimed advantage of synthetic nicotine is the absence of genotoxic impurities that form during the extraction process of nicotine. These impurities are other plant alkaloids, phenolic compounds, and heavy metals. Additionally, the U. S. FDA has implemented new regulations on the quality control of synthetic nicotine. However, only a very few research articles have been published on assessing the complete impurity profile of synthetic nicotine. Therefore, the need to know the composition difference between tobacco-extracted nicotine vs. synthetic nicotine is highly necessary. In this research study, the impurity profile of thirteen different lots of synthetic nicotine was compared with fourteen lots of nicotine extracted from plants using in-house analytical methods. First, the samples were tested for other alkaloids and phenols by reversed-phase High-Performance Liquid Chromatography (HPLC). Second, the chiral purity was analyzed by normal phase HPLC. Third, lead and arsenic content were tested by atomic absorption and fluorescence spectrometry. Fourth, nicotine-specific nitrosamines were tested by LC-MS. The reversed phase HPLC data suggested similar quantities of total impurities in both synthetic and tobacco-extracted nicotine (0.1%). However, synthetic nicotine lacks some impurities such as cotinine, nornicotine, and nicotine-N-oxide. Additionally, the synthetic nicotine lots used in this study have high enantiomeric purity similar to the tobacco-extracted nicotine.

Methyl Gallate Suppresses Canine Mammary Gland Tumors by Inducing Apoptosis and Anti-angiogenesis.

Methyl gallate (MG), a plant phenolic compound, has known anticancer properties. However, its effects on canine mammary gland tumors (CMTs) are unclear. This study evaluated the impact of MG on cell viability, migration, and apoptosis in two CMT cell lines. CMT-U27 and CF41.mg cells were used. In vitro experiments included MTT and scratch assays, Annexin-V/propidium iodide double staining, immunocytochemistry, and western blot analyses. An in vivo CMT xenograft mouse model was also used to observe the effects of MG on tumor growth and vasculature. Immunohistochemistry was performed to analyze vessel density and apoptosis in tumor tissues. Cell migration and tube formation assays with canine aortic endothelial cells assessed the anti-angiogenic effects of MG. Data showed a significant decrease in cell viability and migration in both CMT cell lines after 24 h exposure to various MG concentrations. MG treatment induced dose-dependent apoptotic cell death and elevated cleaved caspase-3 expression. In vivo experiments confirmed tumor growth suppression 21 days post-treatment with 40 mg/kg MG. Tumor tissues displayed increased cleaved caspase-3 and reduced vessel density. MG also inhibited cell migration and disrupted tube formation in canine endothelial cells. MG has potential as an anticancer drug for CMTs by promoting apoptotic cell death and reducing angiogenesis, highlighting its therapeutic promise.

Aktivitas Antioksidan Ekstrak Etanol 50% dan 70% Daun Kenikir (Cosmos Caudatus Kunth) Dengan Metode DPPH (2,2 Diphenyl-1 Picrylhydrazyl)

Antioxidants are molecules that work by warding off free radicals thereby reducing the damaging effects of free radicals. Coronary heart disease is a disease caused by free radicals. Kenikir leaves contain quite high flavonoid metabolite compounds, namely 12.197 mg QE/g. Flavonoids are among the largest natural phenolic compounds in plants that have bioactivity as medicines. The benefits of flavonoids are as anticancer, antifungal, anti-inflammatory, antimicrobial and antioxidant. The aim of this research was to determine the antioxidant activity of 50% and 70% ethanol extract of kenikir leaves (Cosmos caudatus Kunth.) using the DPPH method. This type of research is analytic cross sectional. The results of this study indicate that there is antioxidant activity of 50% and 70% ethanol extract of kenikir leaves (Cosmos caudatus Kunth.) using the DPPH method. The lowest IC50 value was 70% ethanol extract of kenikir leaves, namely 45.573 ± 0.241 ppm. The highest potential antioxidant activity is 70% ethanol extract of kenikir leaves with an IC50 value of 45.573 ± 0.241 ppm. The highest total flavonoid content was 70% ethanol extract of kenikir leaves, namely 17.209 ± 0.297%. The conclusion of this research is that 70% ethanol extract of kenikir leaves (Cosmos caudatus Kunth.) has the highest antioxidant activity with an IC50 value of 45.573 ± 0.241 ppm.

Advanced technology based on Poly(deep eutectic solvent) core–shell nanomaterials enriched with Fructus Choerospondias phenols for efficient defense against UVB-induced ferroptosis

Plant phenolic compounds serve as significant natural antioxidants. However, traditional preparation methods face sustainability challenges. In this study, we synthesized a novel deep eutectic solvent (DES) modified core–shell nanomaterial composed of betaine, ethylene glycol and dopamine hydrochloride based on the spatial arrangement formed by the abundant weak interaction forces in the poly(deep eutectic solvent) (PDES). Utilizing the PDES magnetic nanomaterial and combined with ultrasound-assisted matrix solid phase dispersion (UA-MSPD), it was able to efficiently enrich Fructus Choerospondias phenols (FCP) up to 61.468 ± 0.405 mg/g. Density functional theory (DFT) was used to analyze the adsorption mechanism between the material and the target compounds, which involved weak interactions of electrostatics, hydrogen bonds, and π-π stacking, while maintaining the activity of phenols without destroying the molecular structure. Remarkably, the adsorption efficiency of the material remained above 80 % after six repetitions, indicating excellent reusability. FCPs were identified and analyzed using ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry (UPLC-Q-TOF-MS). The FCP prepared by Fe3O4@SiO2@PDES exhibited superior in vitro antioxidant performance, achieving enrichment and purification in one step. Cell experiment results showed that FCP could scavenge ROS, regulate cytokines, and reduce ferroptosis caused by ultraviolet radiation, making FCP have therapeutic value in practical applications. The technology opens up a new way for the green and sustainable production and enrichment of plant phenolic compounds for anti-aging treatment.

Diversity of plant pollen sources, microbial communities, and phenolic compounds present in bee pollen and bee bread.

The pollination of several crops, as well as wild plants, depends on honeybees. To get the nutrients required for growth and survival, honeybee colonies are dependent on pollen supply. Bee pollen (BP) is partially packed in honeycomb cells and processed into beebread (BB) by microbial metabolism. The composition of pollen is highly variable and is mainly dependent on ecological habitat, geographical origin, honey plants, climatic conditions, and seasonal variations. Although there are important differences between the BP and the BB, little comparative chemical and microbiological data on this topic exists in the literature, particularly for samples with the same origin. In this study, BP and BB pollen samples were collected from two apiaries located in the Campania and Molise regions of Southern Italy. Phenolic profiles were detected via HPLC, while antioxidant activity was determined by ABTS·+ and DPPH· assay. The next-generation sequencing (NGS) based on RNA analysis of 16S (rRNA) and internal transcribed spacer (ITS2) regions were used to investigate the microbial community (bacteria and fungi) and botanical origin of the BP and BB. Chemical analysis showed a higher content of flavonols in BP (rutin, myricetin, quercetin, and kaempferol), while in BB there was a higher content of phenolic acids. The NGS analysis revealed that the microbial communities and pollen sources are dependent on the geographical location of apiaries. In addition, diversity was highlighted between the microbial communities present in the BP and BB samples collected from each apiary.

Adaptation and Validation of a Modified Broth Microdilution Method for Screening the Anti-Yeast Activity of Plant Phenolics in Apple and Orange Juice Models.

Yeasts are the usual contaminants in fruit juices and other beverages, responsible for the decrease in the quality and shelf-life of such products. Preservatives are principally added to these beverages to enhance their shelf-life. With the increasing consumer concern towards chemical food additives, plant-derived antimicrobials have attracted the attention of researchers as efficient and safer anti-yeast agents. However, the methods currently used for determining their anti-yeast activity are time- and material-consuming. In this study, the anti-yeast effect of plant phenolic compounds in apple and orange juice food models using microtiter plates has been evaluated in order to validate the modified broth microdilution method for screening the antimicrobial activity of juice preservative agents. Among the twelve compounds tested, four showed a significant in vitro growth-inhibitory effect against all tested yeasts (Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Zygosaccharomyces rouxii) in both orange and apple juices. The best results were obtained for pterostilbene in both juices with minimum inhibitory concentrations (MICs) ranging from 32 to 128 μg/mL. Other compounds, namely oxyresveratrol, piceatannol, and ferulic acid, exhibited moderate inhibitory effects with MICs of 256-512 μg/mL. Furthermore, the results indicated that differences in the chemical structures of the compounds tested significantly affected the level of yeast inhibition, whereas stilbenes with methoxy and hydroxy groups produced the strongest effect. Furthermore, the innovative assay developed in this study can be used for screening the anti-yeast activity of juice preservative agents because it saves preparatory and analysis time, laboratory supplies, and manpower in comparison to the methods commonly used.

Antibacterial and anti-virulence potential of plant phenolic compounds against Vibrio parahaemolyticus.

Background: Vibrio parahaemolyticus is a pathogenic bacterium that affects shrimp aquaculture; its infection can lead to severe production losses of up to 90%. On the other hand, plant phenolic compounds have emerged as a promising alternative to combat bacterial infections. The antibacterial and anti-virulence activity of the plant phenolic compounds quercetin, morin, vanillic acid, and protocatechuic acid against two strains of V. parahaemolyticus (Vp124 and Vp320) was evaluated. Methods: The broth microdilution test was carried out to determine phenolic compounds' antibacterial activity. Moreover, the biofilm-forming ability of V. parahaemolyticus strains in the presence of phenolic compounds was determined by total biomass staining assay using the cationic dye crystal violet. The semisolid agar displacement technique was used to observe the effect of phenolic compounds on the swimming-like motility of V. parahaemolyticus. Results: Results showed that phenolic compounds inhibited both strains effectively, with minimum inhibitory concentrations (MICs) ranging from 0.8 to 35.03 mM. Furthermore, at 0.125 - 0.5 × MIC of phenolic compounds, V. parahaemolyticus biofilms biomass was reduced by 63.22 - 92.68%. Also, quercetin and morin inhibited the motility of both strains by 15.86 - 23.64% (Vp124) and 24.28 - 40.71% (Vp320). Conclusions: The results suggest that quercetin, morin, vanillic, and protocatechuic acids may be potential agents for controlling V. parahaemolyticus.

Plant metabolic responses to soil herbicide residues differ under herbivory in two woodland strawberry genotypes

The use of glyphosate-based herbicides (GBHs) to control weeds has increased exponentially in recent decades, and their residues and degradation products have been found in soils across the globe. GBH residues in soil have been shown to affect plant physiology and specialised metabolite biosynthesis, which, in turn, may impact plant resistance to biotic stressors.In a greenhouse study, we investigated the interactive effects between soil GBH residues and herbivory on the performance, phytohormone concentrations, phenolic compound concentrations and volatile organic compound (VOC) emissions of two woodland strawberry (Fragaria vesca) genotypes, which were classified as herbivore resistant and herbivore susceptible. Plants were subjected to herbivory by strawberry leaf beetle (Galerucella tenella) larvae, and to GBH residues by growing in soil collected from a field site with GBH treatments twice a year over the past eight years.Soil GBH residues reduced the belowground biomass of the susceptible genotype and the aboveground biomass of both woodland strawberry genotypes. Herbivory increased the belowground biomass of the resistant genotype and the root–shoot ratio of both genotypes. At the metabolite level, herbivory induced the emission of several VOCs. Jasmonic acid, abscisic acid and auxin concentrations were induced by herbivory, in contrast to salicylic acid, which was only induced by herbivory in combination with soil GBH residues in the resistant genotype. The concentrations of phenolic compounds were higher in the resistant genotype compared to the susceptible genotype and were induced by soil GBH residues in the resistant genotype.Our results indicate that soil GBH residues can differentially affect plant performance, phytohormone concentrations and phenolic compound concentrations under herbivore attack, in a genotype-dependent manner. Soil GBH altered plant responses to herbivory, which may impact plant resistance traits and species interactions. With ongoing agrochemical pollution, we need to consider plant cultivars with better resistance to polluted soils while maintaining plant resilience under challenging environmental conditions.

Effect of <i>Meloidogyne incognita</i> infection on the accumulation of phenolic compounds in plants of the genus Mint (Mentha L.)

The purpose of the research is to compare the accumulation of phenolic compounds of different species and varieties of mint, zoned in Central Russia against the background of plant infection by Meloidogyne incognita.Materials and methods. Plants were grown from cuttings in a growing experiment in open ground. Mentha × piperita L. (varieties: Tik-Tak, Orange, Minneola, Mojito, Mitchum, Chocolate), M. spicata L. (varieties Morocco, Crispa) and M. longifolia L. (Longifolia) were taken for the study. A month later, the rooted plants were infected at the rate of 1000 sp. infective larvae of M. incognita per plant. After 8 weeks leaves were fixed in ethanol. The total content of phenolic compounds (PC), phenylpropanoids, flavonoids and catechins was studied using a spectrophotometer. The determination of the total content of PС was carried out using the Folin-Cecolte reagent with measurement at 725 nm, phenylpropanoids – by direct measurement of optical density at 330 nm, flavonoids – by reaction with aluminum chloride at 415 nm, the total content of flavans (catechins - flavan-3-ols), their oligomeric forms – proanthocyanidins, as well as leukoanthocyanidins were assessed by reaction with vanillin at 500 nm.Results and discussion. It has been shown that the accumulation of phenols is related to the species of plants. The varieties Mentha × piperita L. in most cases contained more phenols than M. spicata L. and M. longifolia L. A significant number of PC was noted in the violet-colored varieties Mitchum, Chocolate and Orange. The total content of PC almost completely correlates with the content of their precursors – phenylpropanoids. In terms of the content of flavonoids, the Mitchum variety stands out noticeably, and in terms of the content of catechins, the Orange variety stands out. Nematode infection in most varieties causes a noticeable increase in the total accumulation of soluble PC, phenylpropanoids and flavans, but leads to a decrease in the content of flavonoids.

Plant hormones and phenolic acids response to UV-B stress in Rhododendron chrysanthum pall

Our study aims to identify the mechanisms involved in regulating the response of Rhodoendron Chrysanthum Pall. (R.chrysanthum) leaves to UV-B exposure; phosphorylated proteomics and metabolomics for phenolic acids and plant hormones were integrated in this study. The results showed that UV-B stress resulted in the accumulation of salicylic acid and the decrease of auxin, jasmonic acid, abscisic acid, cytokinin and gibberellin in R.chrysanthum. The phosphorylated proteins that changed in plant hormone signal transduction pathway and phenolic acid biosynthesis pathway were screened by comprehensive metabonomics and phosphorylated proteomics. In order to construct the regulatory network of R.chrysanthum leaves under UV-B stress, the relationship between plant hormones and phenolic acid compounds was analyzed. It provides a rationale for elucidating the molecular mechanisms of radiation tolerance in plants.

FEATURES OF ACCUMULATION OF PHENOLIC COMPOUNDS IN ENDEMIC SPECIES ASTRAGALUS IONAE PALIBIN AND A. PALIBINII POLOZHIJ GROWING ON THE TERRITORY OF THE REPUBLIC OF KHAKASIA

The features of the accumulation of flavonoid glycosides and hydroxybenzoic and hydroxycinnamic acids have been studied in the leaves of endemic Astragalus ionae Palibin and A. palibinii Polozhij of different ecological and geographical growing conditions of the Republic of Khakasia by HPLC method. Luteolin-7-glucoside, rutin, kaempferol-3-O-β-rutinoside, and 3 quercetin glycosides were identified from 8 glycosides of flavonoids from the leaves of A. ionae plants. Six flavonoid glycosides were found in the leaves of A. palibinii, luteolin-7-glucoside, rutin, kaempferol-3-O-β-rutinoside, and isorhamnetin-3-O-β-rutinoside were identified. No differences were found in the composition of hydroxybenzoic and hydroxycinnamic acids in plants of the studied taxa. Gallic, p-hydroxybenzoic, neochlorogenic, chlorogenic, caffeic, p-coumaric, and ferulic acids were identified in the leaves of A. ionae and A. palibinii. The differences between these species in terms of the content of phenolic compounds are most pronounced in the fact that A. ionae plants accumulate more luteolin-7-glucoside, the sum of flavonoid glycosides, and hydroxybenzoic acids. The content of phenolic compounds in plants of different coenopopulations is influenced by ecological and coenotic factors. In arid xerophytic and petrophytic communities more characteristic of these species, more caffeic acid and rutin accumulate, as well as the amount of hydroxycinnamic acids.

Procatechuic acid and protocatechuic aldehyde increase survival of Caenorhabditis elegans after fungal infection and inhibit fungal virulence.

Protocatechuic acid (PCA) and protocatechuic aldehyde (PAL) are important phenolic compounds in plants. We here investigated their possible beneficial effect against fungal infection and the underlying mechanism. The model animal of Caenorhabditis elegans was used as host, and Candida albicans was used as fungal pathogen. The nematodes were first infected with C. albicans, and the PCA and PAL treatment were then performed. Post-treatment with 10-100μM PCA and PAL suppressed toxicity of C. albicans infection in reducing lifespan. Accompanied with this beneficial effect, treatment with 10-100μM PCA and PAL inhibited C. albicans accumulation in intestinal lumen. In addition, treatment with 10-100μM PCA and PAL suppressed the increase in expressions of antimicrobial genes caused by C. albicans infection. The beneficial effect of PCA and PAL against C. albicans infection depended on p38 MAPK and insulin signals. Moreover, although treatment with 10-100μM PCA and PAL could not exhibit noticeable antifungal activity, PCA and PAL treatment obviously suppressed biofilm formation, inhibited hyphal growth, and reduced expressions of virulence genes (ALS3, CaVps34, Vma7, Vac1, and/or HWP1) related to biofilm formation and hyphal growth in C. albicans. Therefore, our data demonstrated the potential of PCA and PAL post-treatment against fungal infection and fungal virulence.

Evolution of Leaf Chlorophylls, Carotenoids and Phenolic Compounds during Vegetation of Some Croatian Indigenous Red and White Grape Cultivars.

During the ripening process of grapes, the grapevine leaves are the most active green organs that are important for photosynthesis, which is closely linked to the development and metabolism of the plant. The detection of plant pigments and phenolic compounds in grapevine leaves can be a good indicator of the ageing process, vine vigor and the plant's ability to respond to fungal attack. In a one-year study, the development of leaf chlorophylls, carotenoids and phenolic compounds during the ripening of six indigenous Croatian grape cultivars and the international cultivars Merlot and Chardonnay was investigated. The chlorophyll a/b ratio and total chlorophyll and total carotenoid concentrations were also investigated. PCA was used to highlight relevant information from the data with the aim of distinguishing individual compounds based on the cultivar and phenological stage. The leaf total hydroxycinnamic acid and flavan-3-ol concentrations decreased slowly during grape development, with the highest concentration immediately after flowering and the lowest during grape ripening. The concentrations of β-carotene, lutein and xanthophylls tended to decrease during bunch closure or veraison, while the concentration of chlorophylls a and b peaked during veraison and then decreased during grape ripening. This research will provide an opportunity to select cultivars with the physiological adaptation to synthesize secondary metabolites that are important for managing stress conditions.

Cyanobacterial elicitor enhances the biomass of Mentha piperita L. and improves the production of high-value rosmarinic acid under in vitro culture of apical meristem

BackgroundRosmarinic acid (RA), like other phenolic compounds, is sources of antioxidants and anti-inflammatory agents in medicinal plants. In vitro culture of plants can improve the medicinal plants’ metabolite profile and phenolic compound quantity. To date, various methods have been proposed to increase this medicinal metabolite in plants, among which the use of bioelicitors can be mentioned. In the present study, a native isolate of heterocystous cyanobacteria, Nostoc spongiaeforme var. tenue ISB65, was used to stimulate the production of biomass and content of RA in Mentha piperita L. (peppermint) grown in vitro from apical meristem. Mentha piperita L. explants were inoculated in half strength Murashige and Skoog (1/2 MS) medium containing cyanobacterial lysate (CL). After 50 days of culturing, the growth indices, the content of photosynthetic pigments, and RA in control and treated plants were measured.ResultsCL inoculation resulted in a significant enhancement in the vegetative growth indices of peppermint, including root and shoot length, plant biomass and leaf number. The content of photosynthetic pigments also increased in cyanobacteria-treated plants. Inoculation with CL increased the RA content by 2.3-fold, meaning that the plants treated with CL had the highest RA content (7.68 mg. g− 1 dry weight) compared to the control (3.42 mg. g− 1 dry weight). Additionally, HPLC analysis revealed the presence of several auxins in CL.ConclusionsThe presence of auxins and the chemical content of CL such as K+ and Ca2+, as regulators of metabolic pathways and molecular activities of cells, may be responsible for the enhanced growth and phenolic compounds of plants under tissue culture conditions. An improvement in RA content in the tissue culture of medicinal plants treated with CL was reported for the first time in this investigation.

The role of valorised plant proteins and phenolic compounds on the digestibility of foods: a short review of recent trends and future opportunities in addressing sustainability issues

During the last 2–3 decades there has been increasing attention from academics, professionals and consumers about how phenolic compounds from plant based foods could enhance the nutritional quality of foods. This mini-review evaluates the focus given to the interactions phenolics have on the metabolic functions in foods and how these phenolic compounds can manipulate digestibility of both carbohydrates and proteins, and how this in turn can modulate metabolic disorders as well as microbiota. With an emphasis on research published in the last decade, the article also examines the potential of valorisation strategies to reutilise fractions which may have traditionally been lost in the food production operations. The reason for this focus is related to the pressing requirements of sustainability within the resource hungry food industry, and how we can create a culture of regenerative food innovation within the sectors.

Characterization and evaluation of antibacterial, antioxidant and cytotoxic activities of green synthesized silver nanoparticles using Haloxylon persicum

The biological synthesis of metal nanoparticles is considered a fast, environmentally friendly and cost-effective technology. This study investigated the synthesis of silver nanoparticles (AgNPs) using the aqueous extract of Haloxylon persicum leaf as a rangeland plant. The formation of AgNPs was examined by UV–Vis spectroscopy, X-ray diffraction, Fourier transform infrared (FTIR), energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM). The color change of the sample from yellow to brown and the absorption peak of about 430 nm showed the synthesis of AgNPs. X-ray diffraction analysis demonstrated AgNP crystal planes with a face-centred cubic (FCC) structure at (111), (200), (220), and (311). FTIR analysis revealed that nanoparticles are coated with plant compounds and phenolic compounds; tannins and flavonoids in the extract act as reducing and stabilizing agents. EDX analysis showed a distinct peak at 3.0 kV, which indicated the successful synthesis and high purity of the AgNPs. Electron microscopy estimated the average size of synthesized AgNPs to be 10 nm. Analysis of the results of the total antioxidant capacity and free radical scavenging activity showed that the synthesized AgNPs have higher antioxidant activity than the plant extract. Also, the AgNPs indicated antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The results of this study provide the field of further development of antibacterial and antioxidant drugs using cost-effective and environmentally friendly methods.

Stability and Bioaccessibility of Lignans in Food Products.

Lignans are a group of plant phenolic compounds with various technofunctional and health-promoting properties. They can be found in oilseeds (291.7-2513 mg/100 g), nuts, vegetables, fruits, and alcoholic and nonalcoholic drinks. The most common structural representative feature of lignans' backbone is a dimeric phenylpropanoid, which consists of two C6-C3 units joined by a central carbon. Compared to other phenolics, such as flavonoids, the literature on lignan stability and bioaccessibility is limited. This Mini-Review aims to present an overview of recent literature, draw connecting lines to the known regarding polyphenols, and suggest the main knowledge gaps. Processing methods and processing conditions influence the stability of lignans with several thermal treatments explored. Roasting, as a major studied processing step, displayed varying effects as a function of the lignan structure and matrix. The content of specific and even total lignans was shown to increase in some cases even after intense thermal treatment. Lignans were also reported to present a stabilizing effect against oxidation to oils when added externally. Different fermentation methods presented inconclusive outcomes on the content of lignans, likely stemming from the various matrices and microorganisms studied in a relatively limited pool of studies. The bioaccessibility of lignans in in vitro studies was usually low (from less than 1% in fermented flaxseed to 30% for microwaved artichokes). Yet, a clear conclusion regarding the digestive fate of lignans as a function of processing and structure cannot be currently suggested, and significant additional effort in this direction is needed.

ACETONE PRECIPITATION OF PROTEINS FOR DETERMINATION OF THE OF ENZYMES ACTIVITY IN MEDICINAL PLANTS

Plant phenolic compounds are widely used in medicine and agriculture. The study of the mechanisms of their biosynthesis and accumulation is a complex task. It is also true for the determination of the activity of the key plant enzymes such as shikimate dehydrogenase. At the same time, the isolation of proteins and enzymes from plant is complicated by the presence of phenolic compounds and pigments. The aim of the research was to evaluate the feasibility of the acetone precipitation of proteins of leaf extracts of plants to determine the activity of shikimate dehydrogenase. The object of the study was the leaves of sea buckthorn (H. rhamnoides) and silky dogwood (C. sericea). The proteins were precipitated from the crude extract with cold (-20 °C) acetone in varying ratio followed by washing three times with acetone and final dissolution in buffer. The activity of shikimate dehydrogenase was determined at pH=10.0 and expressed in ncat per mg of protein. Protein fractions with different activity of shikimate dehydrogenase were isolated from the leaves of sea buckthorn (H. rhamnoides) and silky dogwood (C. sericea). It was shown that the protein fraction with a ratio of 1 : 1.5 of extract : acetone (60% saturation) is most convenient to work with, has a high enzyme activity and does not contain colored impurities. This method of protein isolation and pre-purification is fast, requires a small amount of sample, and suitable for screening studies of the activity of various enzymes in medicinal plants.

Effect of Flavonoids in Preventing Breast Cancer: A Review

Epidemiological research has found a wide range of environmental and dietary risk factors for different cancers nowadays. The four most prevalent cancers— breast, colorectal, lung, and prostate—have all been linked to lifestyle factors in affluent nations. Flavonoids are a significant group of phenolic plant compounds made up of derivatives of 2-phenyl-benzopyrone. Flavonoids, foods such as fruits, vegetables, cereals, bark, roots, stems, flowers, tea, and wine include a group of chemical compounds with different phenolic structures. There are currently efforts being made to separate the purported flavonoids from the other components because these natural chemicals have numerous beneficial health effects. The various sources of flavonoids, their subclasses, and how they aid in the prevention of breast cancer will be outlined in this review article.