1.The In vitro study on the effect of the bioactive fraction of Rhododendron adamsii on the end products of TLR4 signaling
Otgontuya N ; Badmaarag B ; Khashchuluun S ; Onon Ch ; Oyun S ; Tsogtsaikhan S ; Erdenezaya O ; Chimidtseren S
Mongolian Journal of Health Sciences 2025;85(1):239-243
Background:
Rhododendron adamsii (Sagaan Dalya) is a medical plant widely distributed in the Altai region, Mongolia,
and Russia. It is traditionally used for its calming, restorative, and immune-boosting properties. Inflammation is a complex immune response against pathogens such as bacteria, viruses, and fungi, involving macrophages, fibroblasts, mast
cells, and neutrophils. These cells release inflammatory mediators such as nitric oxide (NO), TNF-α, and IL-1β.
In collaboration with the Russian Foundation for Basic Research, a project was initiated to investigate the bioactive fractions of Rh. rosea (L.) and Rh. adamsii and their effects on the production of TLR4 signaling end products
and associated protein activation. Previous studies within this project have shown that certain bioactive fractions exhibit
anti-inflammatory activity. Specifically, fraction 7.11 suppressed NO production and inflammatory signaling molecules
in LPS-stimulated RAW 264.7 macrophages, while fractions 7.46 and 7.52 influenced the phosphorylation of proteins
such as ERK1/2, JNK, and IRF3. These findings suggest the need for further investigation into the effects of Rh. adamsii
bioactive fractions on inflammatory signaling pathways.
Aim:
This study aims to evaluate the effects of bioactive fractions derived from Rhododendron adamsii on the production
of TLR4 signaling end products in RAW264.7 macrophage cell cultures.
Materials and Methods:
The study was conducted using RAW264.7 macrophage cell cultures and bioactive fractions
extracted from Rh. adamsii, dividing the experiments into three groups. After stabilization, RAW264.7 cells were stimulated with 100 ng/mL LPS. Based on previous studies, non-toxic concentrations of bioactive fractions (10 µg/mL) were
applied. NO production was measured using the Griess assay, while TNF-α and IFN-β cytokine levels were evaluated
using ELISA. Each experiment were repeated three times, and data were statistically analyzed using SPSS 25.0, applying
One-way ANOVA and Independent Samples T-test.
Results:
The NO production in the positive control group was significantly higher compared to the negative control. In
contrast, the experimental groups showed a statistically significant reduction in NO production, suggesting a potential inhibitory effect on TLR4 signaling in macrophages. However, fraction 7.48 reduced TNF-α levels while increasing IFN-β
production, but these changes were not statistically significant. Similarly, fraction 7.55 slightly reduced TNF-α and IFN-β
levels, but the effect was also statistically unsignificant.
Conclusion
The bioactive fractions 7.48 and 7.55 of Rh. Adamsii reduced nitric oxide (NO) production in LPS-stimulated macrophage cell line cultures, suggesting that they may inhibit TLR4 signaling. However, their lack of effect on
TNF-α and IFN-β production indicates that they do not influence TLR4 signaling mediated by these cytokines. Instead,
they may affect the final product output through other pathways or different stages of signal transduction.
2.Assessment of the biofilm-forming ability of Staphylococcus aureus
Amgalanzaya D ; Batzaya B ; Uranchimeg R ; Badmaarag M ; Sarantuya J ; Munkhdelger Ya
Diagnosis 2025;115(4):43-50
Staphylococcus aureus (S. aureus) is a clinically significant pathogen widely distributed in food production environments. Its ability to form biofilms on food contact surfaces enhances 50 environmental persistence, increases antibiotic resistance 10–1500-fold, and poses serious challenges for food safety and public health. In Mongolia, data on the biofilm-forming ability of S. aureus in meat processing and retail environments are limited. A cross-sectional study was conducted on 437 samples collected from meat supply and retail sites, including raw meat, aprons, counters, trolleys, and workers’ hands. Isolation and confirmation of S. aureus were performed using MNS 6308:2012 and ISO 6888-1:2021 standards, followed by PCR amplification of the species-specific nucA gene (270 bp). Biofilm formation was evaluated using the microtiter plate assay with 0.5% glucose supplemented tryptic soy broth and optical density at 490 nm, and confirmed by scanning electron microscopy (SEM). Statistical analyses were performed using chi-square tests with p< 0.05 considered significant. Of the 437 samples, 14.2% (62/437) were contaminated with S. aureus. Contamination was higher in retail markets (25.9%) than supply sites (9.3%). Among isolates, 40.3% exhibited biofilm-forming ability: 29.0% weak, 9.7% moderate, and 1.6% strong. Biofilm formation did not significantly differ by sampling site or sample type (p>0.05). SEM imaging revealed distinct biofilm architectures with polysaccharide matrices at 80,000× magnification. A considerable proportion of S. aureus isolates from meat processing and retail environments exhibited biofilm forming ability, posing a potential risk for cross-contamination and persistent foodborne transmission. Strengthened hygiene and sanitation measures are essential to control biofilm-associated S. aureus contamination in Mongolia’s meat production and supply chain.
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