Background: Due to Mongolia’s harsh climate and seasonal limitations in fresh food supply, fruits, vegetables, and medicinal plants are often consumed in preserved forms. However, the preservation methods and storage conditions may significantly alter their antioxidant activity, which is crucial for mitigating oxidative stress and preventing chronic diseases. Objective: This study aimed to evaluate the antioxidant activity of 19 commonly consumed vegetables, berries, and dried medicinal plants under different storage conditions including fresh, cold storage (cellar), and frozen (-20°C). Methods: Samples were extracted in 80% methanol and tested using the DPPH radical scavenging assay. Absorbance was measured at 517 nm using a UV-Vis spectrophotometer. IC⁻⁻ values were calculated to compare antioxidant potency. Statistical differences were assessed using paired and unpaired t-tests with SPSS v27 (p<0.05) Results: Cold storage significantly reduced antioxidant activity in root vegetables, with IC⁻⁻ values increasing by 2.4 to 13.5 times (p<0.01), indicating diminished radical scavenging potencial. In contrast, frozen samples showed minimal change (p>0.05). Dried medicinal plants such as Rosa canina and Thymus serpyllum maintained strong activity, with IC⁻⁻<50 μg/mL. Conclusion Cellar storage leads to a notable decline in antioxidant capacity of common vegetables, while freezing is a more effective method for preservation. Dried medicinal herbs remain potent sources of antioxidants and may be recommended for year-round use in Mongolian diets.

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.

Background: To prevent and combat the spread of the COVID-19 pandemic, the Government of Mongolia has implemented measures such as movement and time restrictions, social distancing and isolation, closure of schools, kindergartens and public places, immunization, and others. It has caused adverse consequences for people, social relations, and the economy, causing health, social, economic, and humanitarian crises. Not only does this situation, medical students, as frontline healthcare workers, are more susceptible to virus infection. Vaccines against COVID-19 have been researched quickly due to the pandemic and are being used under emergency use authorization. In our country the approach of mixing vaccine doses from different manufacturers was used (fractional doses). Therefore, there is no study on the exposure of medical students to the COVID-19 infection and the adverse effects after receiving a dose of a heterologous vaccine. Objective: To study the exposure to the COVID-19 infection and vaccination status of medical students. Methods: The survey was conducted from November 2023 to December 2023 using a cross-sectional study design, and 170 students who study at ASUSU and live in the dormitory were included. Results: A total of 170 students participated in the study. 55.9% (n=95) of them were in the first year, 22.4% (n=38) were in the second year, 10% (n=17) were in the third year, 7.6% (n=13) were in the fourth year, 2.4% (n=4) were from the 5th year and 1.8% (n=3) were from the 6th year students. 88.2% (n=150) of students were female and 11.8% (n=20) were male. In this study, 37.1% of the students were infected by COVID-19 infection previously. Among them, 50% of the students were infected from family members, 16.7% from the school environment, and 15.2% did not know about the source of infection. 76.2% of the respondents were diagnosed with COVID-19 in a medical institution, and forty-one students answered that they were treated at the hospital. 83% of the cases were treated at home and were cured within 14 days. In contrast, 93.8% of the hospitalized students were treated within four months to 1 year. The current study demonstrates neurological, respiratory, sensory, cardiovascular, psychiatric, digestive, and dermatological symptoms were in 37.6%, 24.1%, 27.6%, 17.6%, 11.8%, 11.2%, and 10% of the students who participated in the study, respectively. For a year or more, symptoms of all organ systems were present, but neurological symptoms appeared to be the highest. 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine, 3.5% (n=6) did not receive the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects and 65% (n=106) had no side effects. Conclusion In this study, 37.1% of the students were infected by COVID-19 infection previously. According to the current study, symptoms related to the nervous system was the most prevalent and 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects.