Research on Indigo Naturalis and Ulcerative Colitis
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Following our introduction to Indigo Naturalis (IN), let's explore the scientific investigations that shed light on its potential role in relation to Ulcerative Colitis (UC).
Recent research has focused on understanding how this traditional herbal substance interacts with the complex inflammatory processes and mucosal changes characteristic of UC.
Preclinical Findings: Insights from Rat Studies A pivotal study conducted using dextran sodium sulphate (DSS)-induced UC rat models provided significant insights into the effects of IN. Oral administration of IN was observed to markedly reduce key indicators of UC severity in these models:
• Disease Activity Index (DAI): The study indicated a significant attenuation of elevated DAI scores, suggesting an influence on symptoms such as body weight loss, stool consistency, and fecal occult blood.
• Histological Damage Score (HDS): Histological analysis revealed that IN treatment significantly reduced congestion, edema, and inflammatory cell infiltration in the colonic mucosa, suggesting a potential role in maintaining tissue integrity.
• Myeloperoxidase (MPO) Activity: IN treatments, particularly at medium and low doses, were observed to significantly decrease MPO activities in the colon, which is an important indicator of inflammatory cell infiltration.
Furthermore, research suggested an ability of IN to modulate cytokine levels involved in inflammation and repair processes:
• Pro-inflammatory cytokines such as interleukin (IL)-1α, IL-1β, and IL-18 were observed to be reduced in both serum and colonic tissue, levels of which are typically elevated in UC.
• Conversely, cytokines associated with mucosal repair, specifically epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF), which are important for promoting healing and regeneration of vascular injuries, were observed to increase.
• Notably, high doses of IN were also observed to enhance the content of occludin protein in the colonic mucosa, a tight junction protein vital for maintaining the intestinal barrier, which is often compromised in active UC patients.
Clinical Trial Findings: Observations in Human Patients A multicenter, double-blind, placebo-controlled trial conducted in Japan further evaluated IN in patients with active UC (Mayo scores of 6 or more). The results were compelling, with significant observations:
• A significant, dose-dependent linear trend in proportions of patients with clinical responses was observed across all IN groups compared to placebo. While 13.6% of patients responded to placebo, the response rates for IN were notably higher: 69.6% for 0.5g IN, 75.0% for 1.0g IN, and 81.0% for 2.0g IN daily doses.
• Clinical remission rates were also observed to be significantly higher in the 1.0g IN group (55.0%) and the 2.0g IN group (38.1%) compared to the placebo group (4.5%).
• Impressively, mucosal healing rates were observed to be substantially higher in the IN treatment groups (ranging from 47.6% to 60.0% for IN doses) compared to the placebo group (13.6%).
These findings collectively suggest that IN may influence processes in UC, potentially by modulating inflammation and supporting colonic mucosal damage repair. The observed dose-dependent benefits in human trials further underscore its potential as a subject of ongoing research for UC management.
