The effect of the bioactive fraction extracted from Rhododendron Adamsii on the of TLR4-signaling and its end products

Abstract

Background: Macrophages are key immune cells that respond to infections and regulate pathophysiological conditions such as wound healing. During inflammation, macrophages play important roles in antigen presentation, phagocytosis, and the release of pro-inflammatory cytokines and growth factors. Although inflammation is a defense response of the host against foreign pathogens, an excessive inflammatory response can lead to tissue and organ damage. Rhododendron Adamsii (Rh.Adamsii) is a medicinal plant used in traditional medicine of Mongolia, Buryatia, Tibet and Yakut for soothing and revitalizing purposes. In the pharmacology of traditional medicine, the leaves of the plant are used to induce strength. Researchers have isolated a bioactive fraction from Rh.Adamsii more than 150 bioactive compounds. fraction 7.46 in our study, obtained using methyl tert-butyl ether in chromatographic separation from Rh.Adamsii. Aim: In our investigation, we focused on studying the macrophage immune response influenced by the bioactive fraction obtained from Rh. Adamsii. Specifically, we examined the toll-like receptor 4 (TLR4) signaling pathway in macrophages and explored its impact on the production of pro-inflammatory mediators. Additionally, we investigated how this bioactive fraction might modulate the expression of immune-related genes and affect the overall immune response. Materials and Methods: Fraction No. 7.46 extracted from Rh.Adamsii in the laboratory of the Institute of Biomedicine, Faculty of Biology, Altai University Russia. The cytotoxic effect of bioactive fraction tested on the RAW264.7 mouse macrophage-like cell culture in and the non-toxic dose was determined by the MTT method. The effect on cellular nitric oxide output was determined by the Griess method, the effect on IFNβ output was determined by enzyme-linked immunosorbent assay, and the effect of the fraction on the activation of IRF3 intracellular signaling protein was determined by immunoblotting. Results: 1. Doses of 10.0 and 1.0 μg/mL of fraction 7.46 are not toxic to cells. 2. A dose of 10.0 μg/mL of fraction 7.46 significantly inhibited the production of nitric oxide and IFNβ in RAW264.7 cells. 3. A dose of 10.0 μg/mL of fraction 7.46 has a small inhibitory effect on the activation of IRF3 internal signaling protein in RAW264.7 cells. Conclusions: 1. A dose of 10 µg/mL of Rh.Adamsii fraction No 7.46 was not toxic to RAW264.7 cells (p<0.001). 2. This dose also inhibited the output of nitric oxide and IFNβ (p<0.05). 3. The inhibitory effect of IFNβ may indeed be attributed to its ability to suppress cellular IRF3 signaling.