Navel Orange Peel Fiber Reduces Gut Inflammation via Key Cellular Pathways

Greg Howard
14th May, 2024

Navel Orange Peel Fiber Reduces Gut Inflammation via Key Cellular Pathways

Image Source: Natural Science News, 2024

Key Findings

  • A study by Nanchang University found that bound polyphenols (BPP) from navel orange peel significantly reduce gut inflammation
  • BPP lowered the production of harmful inflammatory markers and cytokines, protecting the intestinal barrier
  • BPP modulates key inflammatory pathways (NF-κB and JAK-STAT), reducing inflammation and preserving gut health
The incidence of autoimmune diseases and inflammatory conditions is on the rise, often attributed to environmental and dietary factors. One of the significant contributors to this increase is the consumption of industrial food additives, which have been shown to disrupt the integrity of the intestinal epithelial barrier, leading to increased intestinal permeability and subsequent autoimmune reactions[2]. Additionally, macrophages, which play a crucial role in maintaining intestinal immune homeostasis, can become dysregulated in the presence of chronic inflammation, contributing to diseases such as inflammatory bowel disease (IBD)[3]. A recent study conducted by Nanchang University has explored the anti-inflammatory properties of bound polyphenols (BPP) extracted from navel orange peel’s insoluble dietary fiber (NOP-IDF)[1]. This study aimed to investigate the molecular mechanisms by which BPP exerts its anti-inflammatory effects using a lipopolysaccharide (LPS)-induced intestinal-like Caco-2/RAW264.7 co-culture inflammation model. The researchers found that BPP significantly reduced the expression of pro-inflammatory markers such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Additionally, BPP lowered the production of pro-inflammatory cytokines, nitric oxide (NO), and reactive oxidative species (ROS) during the inflammatory process. These findings suggest that BPP has a potent anti-inflammatory effect, which could be beneficial in managing inflammatory conditions of the gut. Moreover, BPP was shown to protect the integrity of the intestinal barrier. LPS-induced damage typically results in decreased trans-epithelial electrical resistance (TEER), reduced diamine oxidase (DAO) activity, and lowered intestinal alkaline phosphatase (IAP) activity. Furthermore, LPS downregulates the expression of tight junction proteins such as ZO-1, Occludin, and Claudin-1, which are crucial for maintaining the barrier's integrity. BPP treatment alleviated these detrimental effects, indicating its role in preserving the intestinal barrier function. The study also delved into the molecular mechanisms behind these protective effects. RNA sequencing (RNA-seq) results on RAW264.7 cells in the co-culture model highlighted that the NF-κB and JAK-STAT pathways were significantly affected. These pathways are known to play essential roles in the inflammatory response. Western blot analysis confirmed that BPP modulates these pathways, thereby reducing inflammation. Interestingly, the overexpression of the granulocyte-macrophage colony-stimulating factor (CSF2) gene led to abnormal activation of the NF-κB and JAK-STAT pathways and elevated levels of inflammatory factors. BPP effectively mitigated this abnormal activation, suggesting that its anti-inflammatory action is mediated through the CSF2-NF-κB and JAK-STAT pathways. The findings from this study offer a promising avenue for the development of new therapeutic strategies targeting intestinal inflammation and barrier dysfunction. By modulating key inflammatory pathways and protecting the intestinal barrier, BPP from navel orange peel could potentially serve as a natural anti-inflammatory agent. This is particularly relevant given the increasing prevalence of autoimmune and inflammatory diseases linked to dietary factors and environmental stressors[2][3][4]. In summary, the research conducted by Nanchang University provides compelling evidence that BPP has significant anti-inflammatory properties and can protect the intestinal barrier from LPS-induced damage by modulating the CSF2-mediated NF-κB and JAK-STAT pathways. This study not only expands our understanding of the molecular mechanisms underlying intestinal inflammation but also highlights the potential of natural compounds in managing inflammatory diseases.



Main Study

1) Bound polyphenols in insoluble dietary fiber of navel orange peel modulate LPS-induced intestinal-like co-culture inflammation through CSF2-mediated NF-κB/JAK-STAT pathway.

Published 13th May, 2024

Related Studies

2) Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease.

3) Macrophages in intestinal inflammation and resolution: a potential therapeutic target in IBD.

4) Origin and physiological roles of inflammation.

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