Lavandula angustifolia Herb from Ukraine: Comparative Chemical Profile and in†vitro Antioxidant Activity.

Lavandula L. genus plants have always been relevant as medicines for various purposes in food, medicine, pharmaceuticals, cosmetology and aromology. Ukraine is a new territory in the mass plant cultivation and lavender essential oil production. Therefore, the issue of integrated use of herbal raw materials and their intended use is still relevant. For the first time, ten samples of Lavendula angustifolia herb from 5 growing regions of Ukraine were studied for the composition and content of polyphenols and terpenoids using HPLC and HPTLC methods, respectively, to assess the prospects and quality of herbal raw materials. The results obtained showed that L. angustifolia herb has pronounced antioxidant activity due to the high content of phenolic compounds, namely hyperoside (5.665-11.629 mg/g), vanillic acid (5.986-11.196 mg/g), rosmarinic acid (0.211 to 1.488 mg/g), caffeic acid (0.369-3.835 mg/g), chlorogenic acid (0.239-4.619 mg/g), genistein-7-O-glucoside, as well as due to the presence of linalool and linalyl acetate, which was confirmed by qualitative analysis. The total antioxidant activity was the highest in samples from Lviv Botanical Garden (0.293 Trolox mg/mL), Kyiv OLawander (0.288 Trolox mg/mL), Kharkiv Bohodukhiv (0.270 Trolox mg/mL) which is due to the qualitative composition of phenolic compounds. At the same time, the most intense zones of terpenoids in lavender herb were noted for images from Kharkiv region Lebiazhe and Kitchenkivka villiges. Cluster analysis showed priority in the selection of marker compounds (vanillic acid, hyperoside, chlorogenic acid, rosmarinic acid) for lavender herb based on their quantitative content in the samples. In the future, lavender herb from Ukraine can be considered as a promising raw material with neuroprotective properties as part of its complex use, as research continues.

The Comparative Study of the Antioxidant and Antibacterial Effects of Propolis Extracts in Veterinary Medicine.

Antimicrobial resistance (AMR) is one of the biggest threats to human and animal health. Efforts to combat AMR include the introduction of antimicrobial drugs as alternative treatment options. To contribute to an effective plan for the treatment of infectious diseases caused by bacteria, the development of new antimicrobial agents is increasingly being explored. Propolis has garnered significant attention from both scientists and industry due to its extensive spectrum of biological activity. The growing interest in polyphenols of natural origin and their plant sources further encourages the investigation of their chemical composition and biological effects. Propolis serves as a rich source of phenolic compounds. Baltic region propolis, classified as poplar-type propolis, was selected for this study, and extracts were prepared using raw propolis materials from various Baltic countries. The production of liquid extracts utilized a combination of 70 percent ethanol, a mixture of water and poloxamer P407, and DES (deep eutectic solvent). The research aims to produce liquid propolis extracts using different solvents and to assess their chemical composition, antioxidant, and antimicrobial activity against different veterinary pathogens. Antioxidant activity was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), revealing antioxidant activity in all extracts, with results correlating with the total phenolic compound content. It was found that p-coumaric acid predominated in the studied propolis extracts (in ethanol extracts 1155.90-1506.65 mg/g, in DES extracts 321.13-954.76 mg/g, and in polymeric extracts 5.34-30.80 mg/g), with smaller amounts of ferulic acid and vanillin detected. Clinical and reference bacterial strains were collected from the Lithuanian University of Health Sciences, the Academy of Veterinary Medicine, and the Institute of Microbiology and Virology. To effectively treat bacterial infections, the antimicrobial activity of propolis extracts was tested against six pathogenic bacterial species and one pathogenic fungus (S. aureus, S. agalactiae, B. cereus, E. faecalis, E. coli, P. aeruginosa, and C. albicans). Antimicrobial activity studies demonstrated that DES propolis extracts exhibited stronger antimicrobial activity compared to ethanolic propolis extracts. The minimum inhibitory concentration (MIC) values of DES propolis extracts against the tested strains ranged between 50 and 1000 µg/mL. Considering the study results, it can be concluded that propolis from the Baltic region is abundant in phenolic compounds exhibiting antioxidant and antibacterial activities.

In Vitro and In Silico Anti-Glioblastoma Activity of Hydroalcoholic Extracts of Artemisia annua L. and Artemisia vulgaris L.

Glioblastoma, the most aggressive and challenging brain tumor, is a key focus in neuro-oncology due to its rapid growth and poor prognosis. The C6 glioma cell line is often used as a glioblastoma model due to its close simulation of human glioma characteristics, including rapid expansion and invasiveness. Alongside, herbal medicine, particularly Artemisia spp., is gaining attention for its anticancer potential, offering mechanisms like apoptosis induction, cell cycle arrest, and the inhibition of angiogenesis. In this study, we optimized extraction conditions of polyphenols from Artemisia annua L. and Artemisia vulgaris L. herbs and investigated their anticancer effects in silico and in vitro. Molecular docking of the main phenolic compounds of A. annua and A. vulgaris and potential target proteins, including programmed cell death (apoptosis) pathway proteins proapoptotic Bax (PDB ID 6EB6), anti-apoptotic Bcl-2 (PDB ID G5M), and the necroptosis pathway protein (PDB ID 7MON), mixed lineage kinase domain-like protein (MLKL), in complex with receptor-interacting serine/threonine-protein kinase 3 (RIPK3), revealed the high probability of their interactions, highlighting the possible influence of chlorogenic acid in modulating necroptosis processes. The cell viability of rat C6 glioma cell line was assessed using a nuclear fluorescent double-staining assay with Hoechst 33342 and propidium iodide. The extracts from A. annua and A. vulgaris have demonstrated anticancer activity in the glioblastoma model, with the synergistic effects of their combined compounds surpassing the efficacy of any single compound. Our results suggest the potential of these extracts as a basis for developing more effective glioblastoma treatments, emphasizing the importance of further research into their mechanisms of action and therapeutic applications.

Technological Functionalisation of Microencapsulated Genistein and Daidzein Delivery Systems Soluble in the Stomach and Intestines.

Encapsulating antioxidant-rich plant extracts, such as those found in red clover, within microcapsules helps protect them from degradation, thus improving stability, shelf life, and effectiveness. This study aimed to develop a microencapsulation delivery system using chitosan and alginate for microcapsules that dissolve in both the stomach and intestines, with the use of natural and synthetic emulsifiers. The microcapsules were formed using the extrusion method and employing alginate or chitosan as shell-forming material. In this study, all selected emulsifiers formed Pickering (ß-CD) and traditional (white mustard extract, polysorbate 80) stable emulsions. Alginate-based emulsions resulted in microemulsions, while chitosan-based emulsions formed macroemulsions, distinguishable by oil droplet size. Although chitosan formulations with higher red clover extract (C1) concentrations showed potential, they exhibited slightly reduced firmness compared to other formulations (C2). Additionally, both alginate and chitosan formulations containing ß-CD released bioactive compounds more effectively. The combined use of alginate and chitosan microcapsules in a single pill offers an innovative way to ensure dual solubility in both stomach and intestinal environments, increasing versatility for biomedical and pharmaceutical applications.

Comparative Phytoprofiling of Achillea millefolium Morphotypes: Assessing Antioxidant Activity, Phenolic and Triterpenic Compounds Variation across Different Plant Parts.

Achillea millefolium L., commonly known as yarrow, is a versatile and widely distributed plant species with a rich history of ethnopharmacological significance. This study aimed to evaluate the comparative differences of A. millefolium inflorescence morphotypes. The phytochemical profile of white and pink inflorescence morphotypes was characterised by a complex of thirty-four phenolic and triterpene compounds. The species has distinct morphotypes of white and pink inflorescence. Phenolic and triterpenic profiles were determined, and individual compounds were quantified in inflorescence, leaf, and stem samples of two morphotypes tested. The antioxidant activity of plant extracts was evaluated by free radical scavenging (ABTS) and ferric-reducing antioxidant power (FRAP) assays. Caffeoylquinic acids predominated in all parts of the plant tested. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the principal compounds in the phenolic profile. Betulin, betulinic acid, and α-amyrin were the prevailing triterpenic components in the triterpenic profiles of Achillea millefolium morphotypes. The predominant flavonoids in inflorescences were flavones, while in leaves, flavonols were the organ-specific compounds. The quantitative differences were observed between plant parts of morphotypes. Leaves consistently displayed the highest amounts of identified compounds and have been testified as the main source of antioxidant activity. Overall, white inflorescences accumulated a higher total amount of compounds compared to pink ones. The observed differences between morphotypes derived from the same population reflect the differences in specialised metabolites and their chemotypes. This study addresses gaps in knowledge, particularly in phenolic and triterpenic profiling of coloured inflorescence morphotypes, enhancing our understanding of chemotypes and morphotypes within the species.

Application of Poloxamer for In Situ Eye Drop Modeling by Enrichment with Propolis and Balsam Poplar Buds Phenolic Compounds.

In situ poloxamer-based gels are increasingly being explored as ocular drug delivery carriers to extend the release of active substances, thereby enhancing bioavailability. The objective of this study was to develop thermally stable in situ gels incorporating balsam poplar bud extract, propolis extract, and p-coumaric acid solution and to evaluate the physicochemical parameters of these gelified eye drops. This research assessed the compatibility of poloxamer-based eye drops with active components, their physicochemical properties, stability post-sterilization and during storage, and the release profiles of the active compounds. Fifteen eye drop formulations were prepared and categorized into three groups based on active components. One of the active components was propolis extract. As an alternative to propolis, eye drops containing the plant precursor, balsam poplar bud extract, were developed. The third group's active component was p-coumaric acid, a dominant phenolic acid in propolis and balsam poplar bud extracts. The study reported phenolic contents of 76.63 CAE mg/g for propolis and 83.25 CAE mg/g for balsam poplar bud aqueous extracts, with balsam poplar bud extracts showing higher SPF values (14.0) compared to propolis (12.7), while p-coumaric acid solution exhibited the highest SPF values (25.5). All eye drops were transparent, with pH values meeting the requirements for ocular drops. Formulations containing 8-10% poloxamer 407 met the criteria for in situ gels. All formulations remained stable for 90 days. Conclusion: The study results indicate that the formulated gels possess suitable physicochemical properties, are resistant to applied autoclaving conditions, and exhibit an extended release of active compounds with an increase in poloxamer content.

Development and Evaluation of Two-Phase Gel Formulations for Enhanced Delivery of Active Ingredients: Sodium Diclofenac and Camphor.

The formulation of biphasic gels as potential semi-solid carriers for hydrophilic and lipophilic active substances is promising for the development of pharmaceutical preparations. The aim of this study was to design a stable bigel composition and to determine the influence of the organogel/hydrogel ratio on the gel's physical-chemical and structural-mechanical properties. The investigated compositions of organogel/hydrogel remained stable at ratios ranging from 5/95 to 40/60. After texture and microstructure analysis, bigels with 20/80 and 25/75 ratios were selected as carriers for the active ingredients, sodium diclofenac and camphor, for use as topical preparations for the treatment of muscle-joint inflammation and pain. Although other researchers have published data on the preparation and evaluation of bigels, there are no scientific results on the development of a two-phase gel with our proposed combination of APIs. Sodium diclofenac release was found to be higher when combined with camphor, which revealed the advantages of the biphasic formulation. The pseudoplastic behavior, thixotropy, and thermal stability of flow of the studied bigel samples was investigated by rheological analysis. Ongoing stability studies confirmed the minimal 6-month period.

Impact of Polyvinylpyrrolidone-Vinyl Acetate Copolymer and Sodium Starch Glycolate Excipients on Phenolic Extraction from Red Clover: Enhancing Biological Activity and Antioxidant Potential.

Adding certain excipients during the extraction process can enhance the concentration of target compounds, leading to potentially increased biological properties of the plant extract. This study explores the impact of PVP/VAC and SSG excipients on red clover bud extracts, aiming to enhance their concentration of target compounds and, consequently, their biological properties. The antioxidative potential was evaluated using DPPH, ABTS, and FRAP methods, and the chemical profile was determined using mass spectrometry. Antibacterial activity against various strains was determined through the minimal inhibitory concentration (MIC) method. The results revealed that the excipient-enriched samples exhibited significantly elevated antioxidant activities as well as phenolic and flavonoid contents compared to control samples. Notably, sample V1E3 demonstrated the highest antioxidant potential, with 52.48 ± 0.24 mg GAE/g dw (phenolic content), 463 ± 6.46 µg TE/g dw (ABTS), 12.81 ± 0.05 µg TE/g dw (DPPH), and 29.04 ± 1.16 mg TE/g dw (post-column ABTS). The highest flavonoid content was found in the S1E3 sample-24.25 ± 0.17 mg RU/g dw. Despite the increased antioxidant potential, no significant variance in antimicrobial activity was noted between the test samples and controls. This implies that excipients may hold the potential to enhance the biological properties of red clover extracts for pharmaceutical applications. These findings contribute valuable insights into optimizing extraction processes for improved functionality and application of plant-derived compounds in therapeutic formulations.

Comparative Analysis of Root Phenolic Profiles and Antioxidant Activity of Five Native and Invasive Solidago L. Species.

The high environmental importance of invasive goldenrod has prompted research to find potential benefits that can be derived from these species. This study aimed to identify differences in root phenolic profiles among five Solidago species, thus providing valuable information on their potential applications and the botanical origin of the raw material. The roots of native S. virgaurea L., two alien species S. gigantea Aiton and S. canadensis L. and their hybrids S. ×niederederi Khek and S. ×snarskisii Gudz. & Zaln. were sampled from mixed-species stands in Lithuania. A complex of twelve phenolic acids and their derivatives was identified and quantified in methanol-water root extracts using the HPLC-PDA and LC/MS systems. The radical-scavenging capacities of the extracts were assessed by ABTS. The chemical content of the roots of S. virgaurea, S. gigantea and S. ×niederederi were statistically similar, while the roots of S. canadensis and S. ×snarskisii contained lower amounts of compounds than the other species. The PCA score-plot models of the phenolic profiles only partially confirmed the identification of S. ×niederederi and S. ×snarskisii as crosses between native and alien species. The findings from the phenolic profiles and the observed radical-scavenging activity of root extracts of Solidago species provide valuable insights into their potential applications in various fields.

Balsam Poplar Buds Extracts-Loaded Gels and Emulgels: Development, Biopharmaceutical Evaluation, and Biological Activity In Vitro.

Balsam poplar buds have been used for wound healing and treating irritated skin in traditional medicine. Balsam poplar buds extracts exhibit anti-inflammatory, antioxidant, and antimicrobial effects. In recent years, scientific research has begun to validate some of these traditional uses, leading to an increased interest in balsam poplar buds as a potential source of natural remedies in modern medicine. The study aims to simulate semi-solid pharmaceutical forms with balsam poplar buds extract and evaluate their quality through biopharmaceutical research. The active compounds identified in Lithuanian poplar buds were p-coumaric acid, cinnamic acid, caffeic acid, galangin, pinocembrin, pinobanksin, and salicin. In gels, pH values ranged from 5.85 ± 0.05 to 5.95 ± 0.07. The determined pH values of emulgels ranged from 5.13 ± 0.05 to 5.66 ± 0.15. After 6 h, the release of active compounds from gels and emulgels ranged from 47.40 ± 2.41% to 71.17 ± 3.54. p-coumaric acid dominates in the balsam poplar buds extracts. The pH values of the prepared sem-solid pharmaceutical forms are suitable for use on the skin. The viscosity of the formulations depends on the amount of gelling agent. All formulations showed antioxidant activity. It is relevant to conduct a more extensive study on the influence of the chosen carrier on the release of active compounds from semi-solid formulations with an extract of balsam poplar buds.

Optimization of Delivery and Bioavailability of Encapsulated Caffeic Acid.

Caffeic acid is a widely distributed phenolic acid. It is described in the scientific literature that caffeic acid has poor solubility. The aim of this study was to improve the solubility of caffeic acid for better dissolution kinetics when administered orally. During the study, oral capsules of different compositions were modeled. The results of the disintegration test revealed that the excipients affected the disintegration time of the capsules. The excipient hypromellose prolonged the disintegration time and dissolution time of caffeic acid. The dissolution kinetics of caffeic acid from capsules depend on the chosen excipients. P407 was more effective compared to other excipients and positively affected the dissolution kinetics of caffeic acid compared to other excipients. When the capsule contained 25 mg of ß-cyclodextrin, 85% of the caffeic acid was released after 60 min. When the capsule contained 25-50 mg poloxamer 407, more than 85.0% of the caffeic acid was released from capsules after 30 min. The research results showed that in order to improve the dissolution kinetics of caffeic acid, one of the important steps is to improve its solubility.

Citrus × paradisi L. Fruit Waste: The Impact of Eco-Friendly Extraction Techniques on the Phytochemical and Antioxidant Potential.

Citrus fruits have been the subject of extensive research over the years due to their impressive antioxidant properties, the health benefits of flavanones, and their potential use in the prevention and treatment of chronic diseases. Grapefruit have been shown in studies to improve overall health, with numerous potential benefits, including improved heart health, reduced risk of certain cancers, improved digestive health, and improved immune system function. The development of cyclodextrin complexes is an exciting approach to increasing the content of flavanones such as naringin and naringenin in the extraction medium while improving the profile of beneficial phenolic compounds and the antioxidant profile. This research aims to optimize the extraction conditions of the flavanones naringin and naringenin with additional compounds to increase their yield from different parts of grapefruit (Citrus × paradisi L.) fruits, such as albedo and segmental membranes. In addition, the total content of phenolic compounds, flavonoids, and the antioxidant activity of ethanolic extracts produced conventionally and with -cyclodextrin was examined and compared. In addition, antioxidant activity was measured using the radical scavenging activity assay (ABTS), radical scavenging activity assay (DPPH), and ferric reducing antioxidant power (FRAP) methods. The yield of naringin increased from 10.53 ± 0.52 mg/g to 45.56 ± 5.06 mg/g to 51.11 ± 7.63 mg/g of the segmental membrane when cyclodextrins (α, ß-CD) were used; naringenin increased from 65.85 ± 10.96 µg/g to 91.19 ± 15.19 µg/g of the segmental membrane when cyclodextrins (α, ß-CD) were used. Furthermore, the results showed that cyclodextrin-assisted extraction had a significant impact in significantly increasing the yield of flavanones from grapefruit. In addition, the process was more efficient and less expensive, resulting in higher yields of flavanones with a lower concentration of ethanol and effort. This shows that cyclodextrin-assisted extraction is an excellent method for extracting valuable compounds from grapefruit.

Nutmeg Essential Oil, Red Clover, and Liquorice Extracts Microencapsulation Method Selection for the Release of Active Compounds from Gel Tablets of Different Bases.

The current study presents the most suitable method for encapsulating nutmeg essential oil with liquorice and red clover. Two widely used methods, spray-drying and freeze-drying, were employed to find the most suitable for essential oil volatile compounds' protection. Results showed that freeze-dried capsules (LM) had a higher yield (85.34%) compared to the exact formulation of spray-dried microcapsules (SDM)-45.12%. All the antioxidant and total phenolic compounds' results obtained with the LM sample were significantly higher compared with SDM. LM microcapsules were incorporated in two different bases with no additional sugar (gelatin and pectin) for targeted release. Pectin tablets had firmer and harder texture properties, while gelatin tablets had a more elastic texture. There was a significant impact on texture changes caused by microcapsules. Microencapsulated essential oil with extracts can be used alone or in a gel base (pectin or gelatin, depending on user preferences). It could be an effective product to protect the active volatile compounds and regulate the release of active compounds and give a pleasant taste.

Fractionation and Characterization of Triterpenoids from Vaccinium vitis-idaea L. Cuticular Waxes and Their Potential as Anticancer Agents.

Fruit and leaf cuticular waxes are valuable source materials for the isolation of triterpenoids that can be applied as natural antioxidants and anticancer agents. The present study aimed at the semi-preparative fractionation of triterpenoids from cuticular wax extracts of Vaccinium vitis-idaea L. (lingonberry) leaves and fruits and the evaluation of their cytotoxic potential. Qualitative and quantitative characterization of obtained extracts and triterpenoid fractions was performed using HPLC-PDA method, followed by complementary analysis by GC-MS. For each fraction, cytotoxic activities towards the human colon adenocarcinoma cell line (HT-29), malignant melanoma cell line (IGR39), clear renal carcinoma cell line (CaKi-1), and normal endothelial cells (EC) were determined using MTT assay. Furthermore, the effect of the most promising samples on cancer spheroid growth and viability was examined. This study allowed us to confirm that particular triterpenoid mixtures from lingonberry waxes may possess stronger cytotoxic activities than crude unpurified extracts. Fractions containing triterpenoid acids plus fernenol, complexes of oleanolic:ursolic acids, and erythrodiol:uvaol were found to be the most potent therapeutic candidates in the management of cancer diseases. The specificity of cuticular wax extracts of lingonberry leaves and fruits, leading to different purity and anticancer potential of obtained counterpart fractions, was also enclosed. These findings contribute to the profitable utilization of lingonberry cuticular waxes and provide considerable insights into the anticancer effects of particular triterpenoids and pharmacological interactions.

Application of Antiviral, Antioxidant and Antibacterial Glycyrrhiza glabra L., Trifolium pratense L. Extracts and Myristica fragrans Houtt. Essential Oil in Microcapsules.

Viruses and bacteria can disrupt normal human functions; therefore, ways to use the beneficial properties of plants to promote health are constantly being researched. Plant materials that accumulate biologically active compounds can be used to create a new pharmaceutical form. This study aimed to investigate the biological activity of selected plant extracts and essential oil and to produce microcapsules. The main compounds in extracts and essential oil were determined using chromatographic methods, antioxidant activity was evaluated spectrophotometrically, antimicrobial activity was assessed by monitoring the growth of nine pathogens, and the antiviral effect on infected bird cells with coronavirus was evaluated. Trifolium pratense L. extract had the highest antioxidant (26.27 ± 0.31 and 638.55 ± 9.14 µg TE/g dw by the DPPH and ABTS methods, respectively) and antiviral activity (56 times decreased titre of virus). Liquorice extract expressed antibacterial activity against Gram-positive pathogens and the highest antioxidant activity using the FRAP method (675.71 ± 4.61 mg FS/g dw). Emulsion stability depended on excipients and their amount. Microcapsules with extracts and essential oil were 1.87 mm in diameter, and their diameter after swelling was increased more than two times in intestinal media, while less than 0.5 times in gastric media.

Trends in Phenolic Profiles of Achillea millefolium from Different Geographical Gradients.

The traditional widely used raw material of Achillea millefolium is currently mainly derived from wild populations, leading to diversification and uncertainty in its quality. The aim of the study was to determine the accumulation differences of phenolic compounds between geographically distant populations of Achillea millefolium from northern and southern gradients. Plant material was collected from Gaziantep and Nevsehir provinces in Turkey and from wild populations in Lithuania. A complex of nine hydroxycinnamic acids and eleven flavonoids was identified and quantified in the methanolic extracts of inflorescences, leaves, and stems using the HPLC-PDA method. Caffeoylquinic acids predominated in leaves, while inflorescences tended to prevail in flavonoids. The PCA score plot model represented the quantitative distribution pattern of phenolic compounds along a geographical gradient of populations. The content of phenolic compounds in plant materials from northern latitudes was more than twice that of plants from southern latitudes. A significant correlation of individual phenolic compounds with latitude/longitude corresponded to their differences between two countries. Differences in accumulation of caffeoylquinic acids and flavonoids revealed several intraspecific groups within A. millefolium. Our findings suggest that spatial geographical data on the distribution of phenolic compounds in A. millefolium populations could be used as a tool to find potential collection sites for high-quality raw materials.

Comparison of the Formulation, Stability and Biological Effects of Hydrophilic Extracts from Black Elder Flowers (Sambucus nigra L.).

Elderflower preparations have long been used to treat colds and flu, but their use is undeservedly reduced, and only dried flower teas, less often ethanolic extracts, can be purchased in pharmacies. In the case of homemade teas, the medicinal plant material is extracted with hot water for a relatively short time, thus only a small part of the active substances is extracted. The industrially produced ethanolic extract is rich in active substances, but its use is limited since ethanol in many countries is undesirable and unsuitable for children and geriatric patients. Therefore, the aim of this work was to produce extracts from elder flowers using water as extractant and a mixture of water + polyethylene glycol (PEG) 20%, to compare their chemical composition and stability, and to study the ability to neutralize reactive oxygen species (ROS) and to sustain the viability of C6 glial cells under oxidative stress conditions. The ethanolic extract was used as a standard. Thus, the extract with PEG contained more than two times higher amount of total phenolics (PC) than the aqueous one, and the stability at 6-8 °C was comparable to the stability of ethanolic extract. All three extracts showed an antioxidant effect in a concentration-dependent manner in vitro. However, only the PEG containing extract (at 20-40 µg/mL PC) was the most effective in reducing the intracellular level of ROS and sustaining the viability of glial cells. The results suggest that the co-solvent PEG increases the yield of phenolics in the extract, prolongs the stability, and enhances positive biological effects.

Evaluation of Chemical Composition, Sun Protection Factor and Antioxidant Activity of Lithuanian Propolis and Its Plant Precursors.

The growing interest in polyphenols of natural origin and their plant sources encourages the study of their chemical composition and biological activity. Propolis is widely used as a source of phenolic compounds. The aim of this study is to evaluate and compare the chemical composition, antioxidant activity and sun protection factor (SPF) of the ethanolic extracts of the poplar buds, birch buds and pine buds of propolis plant precursors collected in Lithuania. The IC50 concentration of the extracts was evaluated using DPPH and ABTS methods. Extracts of poplar buds, birch buds and propolis showed a lower IC50 concentration by ABTS and DPPH methods compared with pine buds extracts. Poplar buds and propolis extracts showed the highest SPF value, while birch and pine buds extracts showed a lower SPF value. High-performance liquid chromatography (HPLC) analysis results showed that phenolic acids, such as p-coumaric acid and cinnamic acid, and flavonoids, such as pinobanksin and pinocembrin, were identified in all the tested extracts. Salicin has been identified only in poplar buds extracts. The results of antioxidant activity showed that propolis poplar and birch buds are a promising source of biologically active polyphenols.

Correction: Stanciauskaite et al. Balsam Poplar Buds: Extraction of Potential Phenolic Compounds with Polyethylene Glycol Aqueous Solution, Thermal Sterilization of Extracts and Challenges to Their Application in Topical Ocular Formulations. Antioxidants 2022, 11, 1771.

In the original publication [...].

Balsam Poplar Buds: Extraction of Potential Phenolic Compounds with Polyethylene Glycol Aqueous Solution, Thermal Sterilization of Extracts and Challenges to Their Application in Topical Ocular Formulations.

Phenolic compounds of natural origin have been valued for their beneficial effects on health since ancient times. During our study, we performed the extraction of phenolic compounds from balsam poplar buds using different concentrations of aqueous polyethylene glycol 400 solvents (10-30% PEG400). The aqueous 30% PEG400 extract showed the best phenolic yield. The stability of the extract during autoclave sterilization was evaluated. The extract remained stable under heat sterilization. Ophthalmic formulations are formed using different concentrations (8-15%) of poloxamer 407 (P407) together with hydroxypropyl methylcellulose (0.3%), sodium carboxymethyl cellulose (0.3%) or hyaluronic acid (0.1%). Physicochemical parameters of the formulations remained significantly unchanged after sterilization. Formulations based on 12% P407 exhibited properties characteristic of in situ gels, the gelation point of the formulations was close to the temperature of the cornea. After evaluating the amount of released compounds, it was found that, as the concentration of polymers increases, the amount of released compounds decreases. Formulations based on 15% P407 released the least biologically active compounds. Sterilized formulations remained stable for 30 days.