Background: Tyrosinase is a copper-containing enzyme that catalyzes key initial reactions of melanogenesis, including the hydroxylation of L-tyrosine and oxidation of L-DOPA. The discovery of natural tyrosinase inhibitors remains relevant to pharmaceutical, pharmacognostic, and cosmetic research. Species of the genus Leonurus contain diverse secondary metabolites, including phenolic compounds, phenylpropanoids, flavonoids, iridoids, alkaloids, and diterpenoids. Selected constituents from Leonurus species have previously demonstrated tyrosinase inhibitory properties. However, information on the tyrosinase inhibitory activity of chromatographically fractionated Leonurus sibiricus L. remains limited. Aim: To fractionate the n-butanol fraction of L. sibiricus by centrifugal partition chromatography (CPC), pool the obtained fractions according to their thin-layer chromatographic profiles, and evaluate the mushroom tyrosinase inhibitory activity of the pooled samples to identify the most active chromatographic region. Materials and Methods: The n-butanol fraction of L. sibiricus was separated by CPC, yielding 82 individual fractions. The fractions were analyzed by thin-layer chromatography (TLC) on silica gel using ethyl acetate–methanol (85:15, v/v) as the mobile phase. After development, the chromatograms were derivatized with NPG reagent and visualized under UV light. Consecutive fractions showing comparable TLC band patterns and fluorescence profiles were combined into 15 pooled samples. CPC fractions 59–64 were combined as Sample 11. Tyrosinase inhibitory activity was evaluated using a 96-well microplate spectrophotometric assay with mushroom tyrosinase and L-DOPA as the substrate. Samples were prepared in DMSO at 1 mg/mL. Each reaction contained 100 mM phosphate buffer (pH 6.8), 20 µL of sample solution, and 20 µL of mushroom tyrosinase (500 U/mL). After 10 min of pre-incubation, 80 µL of 8 mM L-DOPA was added, and the reaction was maintained at 25 °C for 20 min. Dopachrome formation was measured at 450 nm using a Promega GloMax Explorer microplate reader. Sample background absorbance was corrected using enzyme- and substrate-free wells, and kojic acid at 1 mg/mL was used as a positive control. Result: The 15 pooled samples demonstrated different levels of tyrosinase inhibitory activity. Sample 11, corresponding to CPC fractions 59–64, showed the strongest inhibitory effect, with 35.89% inhibition. Samples 14, 5, and 3 showed 21.98%, 20.43%, and 16.96% inhibition, respectively, whereas the remaining pooled samples showed lower or negligible inhibition. Kojic acid showed 59.14% inhibition under the same assay conditions. The highest activity observed in Sample 11 suggests enrichment of one or more bioactive constituents within the chromatographic region corresponding to CPC fractions 59–64. Conclusion The combination of CPC fractionation, TLC-guided pooling, and a mushroom tyrosinase–L-DOPA screening assay enabled localization of tyrosinase inhibitory activity within a defined fraction range of L. sibiricus. Sample 11, comprising CPC fractions 59–64, represents the priority material for subsequent LC-MS/MS characterization, bioactivity-guided subfractionation, isolation of active constituents, and concentration-dependent IC₅₀ evaluation.

Background: Panzerina lanata (L.) is widely distributed across various ecosystems in the mountain, steppe, and Gobi regions of Mongolia and has traditionally been used in folk medicine to alleviate joint and muscle inflammation, reduce liver heat, lower blood pressure, promote diuresis, and treat edema and tumors. Its similar applications in Mongolian and Chinese traditional medicine suggest considerable therapeutic potential and biological activity. Studies conducted since 2019 have reported that P.lanata (L.) is rich in phenolic compounds, flavonoids, and antioxidant-active constituents; however, studies on the microscopic and histochemical characteristics of the species growing under Mongolian conditions remain limited, providing the rationale for this study. Aim: To characterize the microscopic features of Panzerina lanata (L.), determine the distribution of starch, polysaccharides, and phenolic compounds using histochemical methods, and evaluate the total polyphenol and flavonoid contents and antioxidant activity. Materials and Methods: For microscopic analysis, plant materials were softened by soaking for 24 h in a 1:1:1 water–ethanol–glycerin mixture (Strich–Fleming solution), followed by preparation of manual transverse and longitudinal sections of the stems, roots, and petals. A 10% chloral hydrate solution was used for clearing. Histochemical analyses were performed using potassium dichromate (K₂Cr₂O₇), ferric chloride (FeCl₃), Lugol’s solution (I₂/KI), thymol (C₁₀H₁₄O) with concentrated sulfuric acid (H₂SO₄), methylene blue (C₁₆H₁₈ClN₃S), and Dragendorff’s reagent. The prepared sections were cleared with glycerin and examined under an Olympus light microscope at ×40 and ×100 magnifications, with images documented using a 12-MP camera. Result: Microscopic examination of the roots, stems, and petals revealed that the root stele exhibited a polyarchy arrangement, with clearly differentiated xylem, phloem, and cambial tissues in both transverse and longitudinal sections. Scalariform tracheary elements in the xylem contributed to water and mineral transport and mechanical support. The stem xylem contained both spiral and scalariform tracheary elements. The petals consisted of cells with double walls and single nuclei, while the floral seed tissue was composed of meristematic tissue associated with continuous cell division, growth, and tissue differentiation. Histochemical analysis of transverse and longitudinal sections of the stems and roots, as well as petal sections, revealed the presence of essential oils, polyphenolic compounds (tannins and flavonoids), and starch. Conclusion Microscopic, histochemical, and phytochemical analyses of Panzerina lanata (L.) revealed the presence of biologically active compounds, indicating its potential for use in the quality evaluation of medicinal plant raw materials.

Background: Numerous experimental and clinical studies have investigated the therapeutic potential of Silybum marianum (L.) Gaertn., mainly attributing its biological activities to antioxidant, anti-inflammatory, antifibrotic, and hepatoprotective effects. In particular, silymarin has been reported to exert hepatoprotective effects by reducing oxidative stress, protecting cell membranes from certain toxic insults, and modulating protein synthesis. Therefore, cultivation of S. marianum and utilization of its seeds for industrial and research purposes are important for establishing a sustainable source of pharmacologically valuable bioactive compounds and increasing the availability of high-quality medicinal plant material. Aim: To evaluate the feasibility of cultivating S. marianum from seeds and to determine seed germination, seedling growth and development, survival after transplantation to open-field conditions, phenological stages, and seed yield characteristics. Materials and Methods: Seeds of S. marianum were germinated under indoor conditions, and normally developed seedlings were subsequently raised in a greenhouse and transplanted to a cultivation site near Tamgan Öndör, Erdene sum, Töv Province, Mongolia. Germination percentage (GP), mean germination time (MGT), seedling growth based on morphometric parameters, and survival rate after transplantation were evaluated. At harvest, the number and diameter of capitula, seed weight per plant, 1000-seed weight, and seed yield per unit area were determined. Data were expressed as mean±SD, and statistical significance was evaluated at p < 0.05. Result: Of the 1,000 seeds sown, 852 germinated, resulting in a germination percentage of 85.2% and a mean germination time of 11 days. Under greenhouse conditions, plant height increased from 1.0 to 3.0 cm, while rosette diameter increased from 1.2 to 7.0 cm. Of the 452 seedlings transplanted to the open field, 353 survived, corresponding to a survival rate of 78.1%. The first flowering was observed on June 12, full flowering on July 9, and full seed maturation on August 30, with 175 days from sowing to seed maturity. On average, each plant produced 18 branches and 20 capitula, with a capitulum diameter of 4.4 cm, seed weight per plant of 15.5 g, 1000-seed weight of 11.5 g, and seed yield of 195.325 kg/ha. Conclusion S. marianum was able to germinate, establish, complete its major growth, flowering, and seed maturation stages, and produce seeds under the cultivation conditions of the Tamgan Öndör area, Erdene sum, Töv Province. These findings indicate that S. marianum can potentially be cultivated in this specific area as a source of medicinal plant material.

Background: Bioactive compounds derived from plants have been extensively studied and widely applied in cosmetic and dermatological fields. In particular, plant-derived polyphenols and anthraquinones are known for their antioxidant properties as well as their ability to inhibit elastase enzyme activity. Elastase is a key proteolytic enzyme responsible for degrading elastin, a structural protein essential for maintaining skin elasticity. Excessive elastase activity contributes to skin aging and wrinkle formation. Therefore, the identification of plant-derived compounds capable of interacting with elastase is of significant importance for improving the composition and efficacy of cosmetic products. Aim: To identify bioactive compounds in the extract of Rheum undulatum L. and to investigate their interaction with elastase enzyme activity. Materials and Methods: The root of Rheum undulatum L. was used as the study material. Sample preparation was performed by grinding the plant root followed by extraction using 50% ethanol assisted by an ultrasonic water bath. The obtained extract was evaporated to dryness using a vacuum centrifugation system to remove the solvent completely. A total of 10 mg of the dried extract was dissolved in 100 µL methanol and 900 µL water, then filtered through a 0.1 µm membrane filter. Subsequently, two sample sets were prepared: a control sample and an elastase-incubated sample at a 1:1 ratio. Both were analyzed using liquid chromatography–mass spectrometry (LC-MS). Data processing was performed using Agilent MassHunter Qualitative Analysis software (version 10.0). Results: LC-MS analysis revealed a total of 16 bioactive compounds in the root extract of Rheum undulatum L. Comparative analysis between the control and elastase-treated samples demonstrated a decrease in the peak areas of gluconic acid and citric acid, while an increase in the peak area of emodin was observed. These changes indicate compositional differences between the two sample conditions. Conclusion The LC-MS analysis of Rheum undulatum L. root extract identified multiple bioactive compounds belonging to anthraquinone, phenolic, and flavonoid classes. Variations in peak intensities between control and elastase-treated samples suggest potential interactions between certain compounds and the enzyme. These findings indicate that the root extract contains biologically active constituents capable of modulating elastase activity, supporting its potential application in anti-aging and cosmetic formulations.

Background: Saponins are secondary metabolites in plants that play an important role in defense mechanisms and physiological processes. Since stomatal cells are crucial for gas exchange and water balance in plant tissues, studying the anatomical and biochemical features of stomatal cells in saponin-rich plant species provides insight into the interactions between these compounds and cellular mechanisms. This serves as the basis of our study. Aim: To determine the structure, types, and functions of stomatal cells in saponin-containing medicinal plants Materials and Methods: During June–September 2024, nine species of saponin-containing medicinal plants were collected from Bulgan, Tuv provinces, and “Gorkhi-Terelj National Park” in Mongolia. Prepared microscopic specimens were examined using macroscopic and microscopic techniques to study the structure, position, number, and epidermal features of stomatal cells. Results: The study revealed that Anemone crinita Juz. exhibited the highest stomatal density (107 stomata/mm²) and epidermal cell density (229 cells/mm²), indicating strong adaptation and protective capacity in arid conditions. Vicia baicalensis (Turcz.) B. Fedtsch. showed the highest stomatal index (39.6), highlighting its significant role in regulating transpiration. Stomatal types varied among species: • Anomocytic stomata were observed in Potentilla multifida and Vicia baicalensis. • Anisocytic stomata were found in Delphinium grandiflorum and Ranunculus borealis. • Paracytic stomata were present in Gentiana algida, Adenophora remotiflora, Helianthemum nummularium, Anemone crinita, and Ranunculus acris. Conclution In the study of the structure, form, and number of stomatal cells in saponin-containing plants growing in Mongolia, Anemone crinita Juz. was found to have the highest number of stomatal and epidermal cells, indicating its high efficiency in gas exchange, water regulation, and protection against external stress. Furthermore, Vicia baicalensis (Turcz.) B.Fedtsch. showed the highest stomatal index, confirming its strong capacity for active regulation of gas exchange. The variation in stomatal cell types among plant species was identified as playing an important role in ecological and biological adaptation as well as protective mechanisms.