Ivanauskas, Liudas

Commercial herbal teas marketed as Epilobium herb are widely consumed in Europe for prostate-related and anti-inflammatory effects. However, they are often sold under generic names without clear species differentiation or quality specifications, raising concerns about chemical consistency and therapeutic equivalence.

Hydrodistillation of aromatic plants for essential oil production generates substantial amounts of solid and liquid residues that are commonly discarded despite their potential value as sources of bioactive compounds. In this study, the essential oil and post-distillation residues of Rhododendron tomentosum Harmaja were evaluated within a waste-to-value framework to recover phenolic compounds with antioxidant and antimicrobial properties. Dry extracts obtained from liquid (DEA) and solid (DEE) residues were characterized in terms of total phenolic and flavonoid contents, antioxidant capacity (DPPH assays), and antimicrobial activity against selected microorganisms. Quantitative HPLC–PDA analysis revealed multiple phenolic compounds. Extracts derived from solid residues exhibited significantly higher phenolic and flavonoid contents and stronger antioxidant activity than those obtained from liquid residues, indicating that solid by-products constitute a richer phenolic matrix. Antimicrobial assays revealed pronounced activity for extracts prepared from plant material harvested in October, particularly those based on propylene glycol and glycerin, which were effective against both Gram-positive bacteria and selected Gram-negative clinical isolates. The essential oil showed broad-spectrum antimicrobial activity, including inhibition of Aspergillus niger. Stability studies demonstrated that the phenolic composition and bioactivity of the dry extracts were largely preserved after one year of storage. These findings demonstrate that R. tomentosum hydrodistillation residues represent a promising source of natural antioxidants and antimicrobial agents, supporting their potential utilization as value-added ingredients in food and cosmetic applications and contributing to circular economy strategies.

A comparative analysis of pentacyclic triterpenoids (ursolic acid and oleanolic acid) in the aerial parts of eleven Epilobium species was performed using high-performance liquid chromatography (HPLC) results. Samples for the analysis were collected from various regions in Ukraine, Poland and Lithuania. Oleanolic acid and ursolic acid were identified and quantified in nine of the species (E. angustifolium, E. montanum, E. collinum, E. roseum, E. palustre, E. tetragonum, E. obscurum, E. nervosum, and E. nutans). However, neither compound was detected in E. parviflorum or E. hirsutum from any collection site, indicating notable chemotaxonomic divergence within the genus. The quantity of ursolic acid in the analysed samples ranged from 20.27 ± 0.49 to 74.84 ± 2.24 mg/100 g dry weight, consistently exceeding that of oleanolic acid (2.03 ± 0.05 to 32.09 ± 0.73 mg/100 g). The highest total triterpenoid content was observed in E. tetragonum. These findings emphasise the importance of oleanolic and ursolic acids as auxiliary chemotaxonomic markers for Epilobium species. Given the well-documented antiproliferative and antiviral activities of these triterpenoids, the present results also suggest that several under-explored Epilobium species could be a promising source of bioactive compounds for further pharmacological research, particularly regarding prostate cancer and viral infections.

Background: During the Soviet occupation, military training was a compulsory component of higher education at Kaunas Medical Institute. Service in the Soviet Army was widely perceived in Lithuania as an obligation imposed by an occupying power. Many young men entered universities in order to avoid conscription, as military service was often associated with humiliation and violence. At a certain period, regulations were changed and all young men were required to perform military service, including university students. Aim: The presentation aims to reconstruct the system of military training at Kaunas Medical Institute, examining its theoretical curriculum, the organization of field training exercises (sborai), and the hierarchical relationship between military instructors and students. Methods: The study is based on the systematization of contemporaries’ memoirs and the personal experience of the presenter. A historical and interpretative approach is used to contextualize military training within Soviet higher education. Results and Conclusion: Military training combined theoretical instruction with practical field exercises conducted under strict regulation. The organization of sborai reflected the broader militarized structure of Soviet society. The relationship between officers and students mirrored the authoritarian hierarchy characteristic of Soviet institutions. The case demonstrates how medical education functioned within a system in which professional training coexisted with political coercion under Soviet rule.

Background: For assessing antioxidant activity of hydrophilic and lipophilic compounds, hydrophilic standards (Trolox, ascorbic acid, gallic acid, rutin, etc.) are most commonly used in spectrophotometric studies. However, for lipophilic substances, it is more appropriate to perform the analysis in non-aqueous conditions and compare their activity with a lipophilic standard. α‑Tocopherol serves as such a standard, demonstrating activity comparable to Trolox (1). Therefore, a DPPH-based method in a non-aqueous medium was developed using α‑tocopherol as a standard and applied to chamomile essential oil. Aim(s): To develop and apply a non-aqueous DPPH spectrophotometric method for the assessment of antiradical activity of lipophilic compounds using tocopherol acetate as a lipophilic reference standard, and to express the activity of chamomile essential oil in tocopherol equivalents. Methods: Tocopherol acetate was dissolved in methanol and diluted (1000–62.5 µg/mL). DPPH (0.003 g/100 mL) in acetonitrile was mixed with 50 µL of tocopherol solution in 5.0 mL and incubated 20 min. Absorbance at 517 nm was measured in triplicate; calibration curve: y = 0.0005x + 0.0141 (R² = 0.9994). Chamomile oil (400 µL in 5 mL methanol) was analyzed similarly; absorbance converted to tocopherol equivalents. Results: A linear calibration curve for tocopherol acetate in 62.5–1000 µg/mL was obtained, demonstrating excellent linearity (R² = 0.9994). The antiradical activity of chamomile essential oil under non-aqueous conditions corresponded to 67.8 µg/mL tocopherol acetate, equivalent to ~3.39 µg per reaction mixture (50 µL added). The analyzed oil in the mixture was ~3.70 µL (50 µL of 7.41% v/v solution). Conclusion: A non-aqueous DPPH method suitable for lipophilic compounds was developed using tocopherol acetate. This enables expressing essential oil activity in tocopherol equivalents, more appropriate than hydrophilic standards in non-aqueous systems. Further studies will integrate HPTLC and GC to determine contributions of individual components.

Background: Ruta graveolens L. has a wide range of ethnopharmacological applications that are confirmed and further explored by modern evidence-based research. In the western regions of Ukraine, the plant has traditionally been used as an anti-inflammatory agent, including herbal baths for the treatment of skin diseases in infants [1]. In Lithuanian local medicine, its use has been documented for the treatment of abdominal pain, nervous and cardiovascular disorders, as well as as an abortifacient [2]. Based on these traditional applications, modern studies investigate the anticancer, neuroprotective, and antimicrobial potential of rue. Aim: To evaluate the content of phenolic compounds in rue as one of the key groups of biologically active compounds potentially responsible for the plant’s therapeutic properties. Methods: The aerial parts of Ruta graveolens were collected at the I. Franko Botanical Garden in 2023. The quantitative determination of total phenolic compounds was performed in methanolic extracts using spectrophotometry on a Halo DB-20 UV–Vis spectrophotometer at 760 nm, employing the Folin–Ciocalteu reagent [3]. Results: The content of phenolic compounds showed a clear dependence on the vegetation phase. A moderately high level was observed during mass budding and the beginning of flowering. The maximum accumulation occurred during mass flowering, with levels approximately 1.2 times higher than in the budding phase, indicating intensified biosynthesis during the active reproductive development stage. During mass fruiting, the content decreased by more than twofold, followed by a secondary increase after fruiting to values comparable to the maximum. Conclusions: The results demonstrate a phenological pattern of phenolic compound accumulation in Ruta graveolens. Considering the established role of phenolic compounds in anti-inflammatory and potential antitumor activities, the mass flowering stage is identified as the optimal phase for harvesting plant material rich in biologically active compounds.

Background: Prunus armeniaca L. is highly valued for its rich phytochemical composition, particularly its phenolic compounds, which are known for their strong antioxidant and health-promoting properties. While most research has concentrated on the nutritional and chemical profile of the fruit, other plant organs, especially the leaves, represent an important yet underexplored source of bioactive phenolics [1]. These compounds may exhibit significant antioxidant, antifungal, antimicrobial, and anticancer activities [2]. Investigating the distribution and composition of phenolic compounds in apricot leaves is therefore essential for evaluating their potential applications in food, pharmaceutical, and agricultural fields. Aim: To determine the total phenolic content and identify marker phenolic compounds in the leaves of Prunus armeniaca L. ‘Shalakh’. Materials and methods: P. armeniaca ‘Shalakh’ variety leaves have been harvested in the Tairov village of Armavir region (Armenia) in May, July and September of 2024. Phenolic compounds were extracted by ultrasonic-assisted extraction using 70% (v/v) ethanol as the solvent. The total phenolic content of the leaf extracts was determined using the well-established Folin–Ciocalteu colorimetric method and expressed as gallic acid equivalents (GAE) [3]. Marker phenolic compounds were identified by high-performance liquid chromatography (HPLC) using a Waters e2695 Alliance HPLC system equipped with a 2998 photodiode array (PDA) detector (Waters, Milford, MA, USA). The identification of individual phenolic compounds was based on a comparison of their retention times (Rt) and UV–Vis spectra with those of authentic reference standards [4]. Results: The total phenolic content of Prunus armeniaca ‘Shalakh’ leaves varied according to the collection period. The highest value was recorded in May (39.24 ± 0.45 mg/100 g DW), while lower values were observed in July (27.84 ± 0.39 mg/100 g DW) and September (27.37 ± 0.39 mg/100 g DW). HPLC analysis identified several phenolic marker compounds, including neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, cynarin, rutin, isoquercitrin, and kaempferol-3-O-rutinoside. Conclusion: Leaves of Prunus armeniaca ‘Shalakh’ contain high levels of phenolic compounds, especially in early development, with 7 compounds identified as the main markers, highlighting their potential for nutraceutical and functional applications.

Background: Marrubium vulgare L. is a perennial herbaceous plant of the Lamiaceae family, native to Europe, North Africa, and Southwest and Central Asia. The plant is widely cultivated in European countries due to its rapid adaptation to the environment. It has been used in traditional medicine for various purposes. It has been proved to possess several properties such as antibacterial, antioxidant, antidiabetic, anti-inflammatory, anti-hypertensive, vasorelaxant, hypoglycemic, cytotoxicity and anticancer activities [1]. Such significiant variation may reflect differences in climate, atmospheric pressure, humidity and edaphic factors, which together shape phenolic accumulation as plants adapt to local bioecological conditions [2]. Aims: To evaluate changes in phenolic compound content of Marrubium vulgare L. across different harvesting years and countries using a spectrophotometric method. Methods: The flowering aerial parts were collected during the flowering stage in Ukraine (2020-2024) and Lithuania (2025) in July. The total phenolic content was determined using Folin-Ciocalteu assay, the absorbance of the solution was measured at 750 nm and expressed as mg/g GAE. Results: Total phenolics content of Marrubium vulgare L., expressed as gallic acid equivalent (mg/g GAE) and spectrophotometric method, ranged from 2.19 to 5.43 mg/g across all harvesting years and locations. Ukrainian herb samples showed the lowest phenolic content in 2021 (2.19 mg/g) and the highest in 2022 (5.43 mg/g), while in 2020, 2023 and 2024 (3.12, 3.40 and 3.60 mg/g, respectively). Lithuanian herb samples collected in 2025 July reached 3.66 mg/g in Simaiciai and 3.81 mg/g in Klaipeda. The observed differences in content depending on the harvesting year are due to differences in climatic conditions (temperature, precipitation, etc.), which can significantly influence the plant secondary metabolites. Furthermore, differences between countries (geographical factors, soil composition) also contribute to these differences. Conclusion: The total phenolic content of Marrubium vulgare L. varied greatly between harvest years in Ukraine and Lithuania, indicating clear differences related to year, climate and geographical location. Further research is needed on environmental and soil parameters that influence the accumulation of phenolic compounds.

Epilobium angustifolium L. is a medicinal plant widely used for its anti-inflammatory, antioxidant, antimicrobial, and antiproliferative properties, attributed to the presence of ellagitannins, flavonoids, and phenolic acids. However, the lack of pharmacopoeial standards for its raw materials limits consistent quality control and broader pharmaceutical use. The aim of this study was to establish approaches to the qualitative and quantitative standardisation of Epilobium angustifolium leaves collected from different geographic regions. Physicochemical parameters, including impurity content, loss on drying, total ash, and acid-insoluble ash, were determined according to the European and Ukrainian Pharmacopoeias. Chromatographic profiling was performed using HPTLC and HPLC-DAD, and the total phenolic compound and flavonoid contents were measured spectrophotometrically. The results showed low levels of foreign matter (1.2%–1.5%) and moisture (6.8%–8.1%), with total ash ranging from 4.2% to 6.0% and acid-insoluble ash from 0.15% to 0.38%. Total phenolic content ranged from 0.77 to 1.44 mg GAE/g dry weight, while total flavonoid content ranged from 0.19% to 0.55%. HPLC analysis identified and quantified 13 major polyphenols, including oenothein B (24.8–60.6 mg/g), oenothein A (0.6–5.8 mg/g), isomyricitrin (17.8–32.1 mg/g), and quercitrin (4.8–10.5 mg/g) as the dominant components. The resulting chromatographic fingerprints and quantitative data demonstrate chemical consistency between samples, with regional variability due to environmental factors. The proposed parameters can serve as a basis for developing quality control standards for raw materials and a pharmacopoeial monograph for Epilobium angustifolium leaves, ensuring reproducible quality and efficacy of herbal preparations.

Background/Objectives: The development of novel small-molecule kinase inhibitors remains an important strategy in anticancer drug discovery. Receptor tyrosine kinases such as c-MET and HER2 are clinically relevant targets involved in tumor progression and resistance mechanisms. The aim of this study was to design, synthesize, and biologically evaluate a series of 3-[(2,4-difluorophenyl)amino]propanoic acid derivatives as potential antiproliferative agents and to explore their possible interactions with selected kinase targets. Methods: A series of ester, hydrazide, hydrazone, semicarbazide, triazolone, and triazolethione derivatives (2–21) were synthesized and structurally characterized by NMR, IR spectroscopy, and microanalysis. The compounds were evaluated for in vitro anticancer activity against A549 and Caco-2 human cancer cell lines. In addition, molecular docking studies were performed to investigate binding interactions with c-MET and HER2 receptor tyrosine kinases. Cytotoxicity toward non-transformed HEK293 cells was also assessed. Results: The synthesized derivatives demonstrated structure–activity relationships, with compounds 6b, 7f, 7g, and 9 exhibiting the most pronounced antiproliferative effects, reducing cancer cell viability by approximately 50% in both tested cell lines. Molecular docking indicated that compound 9 displayed favorable predicted binding energies toward c-MET and HER2, forming hydrophobic and hydrogen-bond interactions within the active sites and showing overlapping contacts with native ligands and reference inhibitors. Active compounds also demonstrated cytotoxic effects in HEK293 cells comparable to those of doxorubicin and cisplatin. Conclusions: These results identify 3-[(2,4-difluorophenyl)amino]propanoic acid derivatives, particularly compound 9, as promising scaffolds for further structural optimization toward the development of kinase-targeting antiproliferative agents.