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Assam Indigo Leaf Extract

Also known as: Assam Indigo Leaf Extract, Qing Dai, Indigofera tinctoria extract, Indigo naturalis

Overview

Assam Indigo Leaf Extract, primarily known as Indigo naturalis, is derived from the leaves of *Indigofera* species, particularly *Indigofera tinctoria*, native to Assam, India. It is a traditional herbal extract containing a complex mixture of blue pigments, including indigo and indirubin, along with tryptamine derivatives. Historically used as a dye, it has found significant application in traditional medicine for its anti-inflammatory, immunomodulatory, antioxidant, and antiviral properties. Research indicates its primary utility in managing inflammatory and autoimmune conditions such as ulcerative colitis (UC) and systemic lupus erythematosus (SLE), as well as promoting wound healing. While some high-quality randomized controlled trials exist for UC, further comprehensive systematic reviews are needed to fully establish its efficacy across all potential applications.

Benefits

Indigo naturalis demonstrates significant benefits, particularly in inflammatory conditions. A multicenter double-blind RCT showed that 2-week treatment with Indigo naturalis (5g daily) significantly improved disease activity scores (Lichtiger index) and albumin levels in patients with mild to moderate ulcerative colitis, with a rapid onset of benefit. This indicates a clinically meaningful reduction in disease activity. Preclinical studies suggest enhanced wound healing through the upregulation of antioxidant enzymes (catalase, SOD, Gpx) and modulation of matrix metalloproteinases and TGF-β1, crucial for tissue repair. Furthermore, potential immunomodulatory effects have been observed in systemic lupus erythematosus (SLE) mouse models, where it reduced kidney inflammation and inflammatory cytokines. These findings suggest its utility for patients with inflammatory bowel disease, particularly UC, and potential application in autoimmune conditions like SLE, as well as for wound healing.

How it works

Indigo naturalis exerts its therapeutic effects through multiple biological pathways. Its anti-inflammatory and immunomodulatory actions involve the downregulation of inflammatory cytokines and modulation of immune checkpoints, such as PD-L1, as observed in SLE models. It also exhibits significant antioxidant activity by increasing endogenous antioxidant enzymes like catalase, superoxide dismutase (SOD), and glutathione peroxidase (Gpx), thereby reducing oxidative stress in affected tissues. In wound healing, it promotes tissue remodeling and repair by inhibiting matrix metalloproteinases and upregulating TGF-β1. Additionally, it has shown antiviral activity through neuraminidase inhibition, suggesting potential against influenza viruses. The primary interactions are with the gastrointestinal immune system, skin tissue repair mechanisms, and systemic immune regulation, though its exact absorption and bioavailability are not fully characterized.

Side effects

Indigo naturalis appears generally safe for short-term use, with mild adverse events being the most commonly reported. In a randomized controlled trial for ulcerative colitis, mild headaches were reported in approximately 20% of patients. No serious adverse events were observed in short-term studies, although historical concerns about pulmonary hypertension and intussusception have been noted, these were not observed in the referenced clinical trial. Uncommon or rare side effects are not well-documented from high-quality studies. Due to its immunomodulatory effects, caution is advised when used concurrently with immunosuppressants, as potential drug interactions are not well-studied. Contraindications are not fully established, but caution is likely warranted in pregnancy, breastfeeding, and severe immunocompromised states. Safety in children and for long-term use has not been established.

Dosage

For mild to moderate active ulcerative colitis, a dosage of 5 capsules (500 mg each) taken twice daily, totaling 5 grams per day, has shown efficacy over a 2-week period. This represents the minimum effective dose identified in a clinical trial. Optimal dosage ranges for other conditions are not well-established, and traditional use may vary. The maximum safe dose is currently unknown. Timing considerations for oral administration typically involve twice-daily dosing. For wound healing, topical application frequency varies in preclinical studies. It is crucial to note that the quality and standardization of commercial products can vary significantly, particularly concerning the concentration of active compounds and the presence of impurities like excessive lime content, which can impact both efficacy and safety. No specific cofactors are identified as required for its action.

FAQs

Is Assam Indigo Leaf Extract safe for long-term use?

Long-term safety data for Assam Indigo Leaf Extract is currently lacking. Short-term use, typically up to 2 weeks, appears generally safe with mild side effects like headaches.

How quickly does it work?

In studies for ulcerative colitis, significant improvements in disease activity were observed within 2 weeks of starting treatment with Indigo naturalis.

Can it be used for autoimmune diseases?

Preclinical evidence suggests potential benefits in autoimmune conditions like systemic lupus erythematosus (SLE), but robust clinical data in humans are still limited.

Is it effective topically?

Yes, animal studies have shown that topical application of indigo extract can enhance wound healing by promoting tissue repair and reducing oxidative stress.

Are there quality concerns with commercial products?

Yes, manufacturing variability and the presence of impurities, such as excessive lime content, can affect the quality and safety of commercial Indigo naturalis products.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC7644062/ – This multicenter, double-blind, randomized controlled trial investigated Indigo naturalis for mild to moderate ulcerative colitis. It found that 5g/day of Indigo naturalis significantly reduced disease activity (Lichtiger index) and improved albumin levels within two weeks compared to placebo, with mild headaches as the main side effect. The study highlights its rapid efficacy and good short-term tolerability for UC.
https://www.phcogres.com/article/2025/17/3/105530pres20252088 – This preclinical animal study demonstrated that topical application of indigo extract enhanced wound healing in rats. It achieved this by upregulating antioxidant enzymes (catalase, SOD, Gpx) and modulating matrix metalloproteinases and TGF-β1, crucial factors in tissue repair. The findings suggest a strong potential for Indigo naturalis in dermatological applications.
https://www.anncaserep.com/open-access/to-study-the-effect-of-indigo-naturalis-on-systemic-lupus-8255.pdf – This preclinical study utilized an autoimmune mouse model (MRL/lpr mice) to investigate the effects of Indigo naturalis on systemic lupus erythematosus. It found that Indigo naturalis reduced kidney inflammation, proteinuria, and inflammatory cytokines, suggesting significant immunomodulatory potential for autoimmune diseases. This provides a basis for further research into its use for conditions like SLE.
https://pmc.ncbi.nlm.nih.gov/articles/PMC7734464/ – This systematic review on Indigo naturalis in traditional medicine highlights its antiviral properties, particularly neuraminidase inhibition, which could be relevant for influenza viruses. It also discusses critical quality control issues, including manufacturing variability and the presence of impurities like lime, which can impact the safety and efficacy of commercial products. The review emphasizes the need for standardization.