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

Moringa oleifera (M. oleifera) 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 M. oleifera 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 (IL-10), while it simultaneously decreased cell apoptosis and the levels of pro-inflammatory cytokines, such as tumour necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6). 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.