The Anti-Inflammatory Properties of Polysaccharides Extracted from Moringa oleifera Leaves on IEC6 Cells Stimulated with Lipopolysaccharide In Vitro

<i>Moringa oleifera</i> (<i>M. oleifera</i>) is a plant with significant medicinal and nutritional value and contains various bioactive compounds, particularly in its leaves (MOL). This study sought to explore the impact of <i>M. oleifera</i> leaf polysaccharides (MOLPs) on lipopolysaccharide (LPS)-activated intestinal epithelial cells (IEC6) and to uncover the mechanisms involved. The cytotoxicity of MOLP on IEC6 cells was assessed using the Cell Counting Kit-8 (CCK-8) assay, which demonstrated a safe concentration range of 0-1280 µg/mL. The impact of MOLP on cell viability was further evaluated over 12 to 48 h. IEC6 cells were treated with three concentrations of MOLP low (25 µg/mL), medium (50 µg/mL), and high (100 µg/mL) alongside LPS (50 µg/mL) stimulation for one day. The findings revealed that treatment with MOLP significantly promoted cell migration and increased the production of interleukin-10 (<i>IL-10</i>), while it simultaneously decreased cell apoptosis and the levels of pro-inflammatory cytokines, such as tumour necrosis factor alpha (<i>TNF-α</i>), interleukin 1β (<i>IL-1β</i>), and interleukin 6 (<i>IL-6</i>). Additionally, MOLP treatments across all concentrations significantly reduced the expression of Toll-like receptor 4 (TLR-4), myeloid differentiation primary response 88 (MyD88), phosphorylated nuclear factor kappa B-alpha (pIκB-α), and phosphorylated NF-κB p65 signalling pathways. Moreover, MOLP restored the expression of tight junction proteins, such as zonula occludens-1 (ZO-1) and occludin, which had been disrupted by LPS. These results indicate that MOLP exhibits anti-inflammatory properties by inhibiting inflammatory signalling pathways and maintaining intestinal barrier integrity through the upregulation of tight junction proteins in IEC6 cells. This study enhances our understanding of the anti-inflammatory capabilities of MOLP.