Baphicacanthus cusia

Baphicacanthus cusia (Nees) Bremek.: A Comprehensive Reference

1. Identity, Taxonomy, and Botanical Description

1.1 Nomenclature and Synonymy

Baphicacanthus cusia (Nees) Bremek. (1944) is a homotypic synonym of the currently accepted botanical name Strobilanthes cusia (Nees) Kuntze (1891), with the basionym Goldfussia cusia Nees (1832). Additional recorded synonyms in the taxonomic literature include Dipteracanthus calycinus Champ., Ruellia cusia Buch.-Ham. ex Wall., Ruellia indigofera Griff., Ruellia indigotica Fortune, and Strobilanthes balansae Lindau. In Chinese medicine and commerce, the plant and its derived products are known under several names. Its stems and leaves are used to produce a traditional Chinese medicine or blue dye called Qing-Dai (indigo naturalis), while its roots are referred to as Nan-Ban-Lan-Gen after processing.

1.2 Taxonomic Classification

Within the plant kingdom, Baphicacanthus cusia belongs to the order Lamiales, family Acanthaceae, subfamily Acanthoideae, tribe Ruellieae, subtribe Strobilanthinae.

1.3 Botanical Description and Distribution

The plant is a herbaceous perennial with a woody stem growing to a height of 30 cm to one metre. Its opposite leaves are serrated and oval-shaped, narrowing to points at each end. Clusters of violet-blue, sometimes white, flowers grow in the axils of its leaves, and its fruit is an oblong-shaped capsule. The species is distributed across Assam, Bangladesh, China (south-central and southeast), the East Himalaya, Hainan, Laos, Myanmar, Taiwan, Thailand, Tibet, and Vietnam. Within China, it is extensively distributed in Southwest China, South China, and East China.

1.4 Pharmacopoeial Status

Both the processed stems and leaves (Qing-Dai / Indigo Naturalis) and the roots (Nan-Ban-Lan-Gen) have been recognized and documented in the Chinese Pharmacopoeia. As a frequently used Chinese herbal medicine for antiviral treatment, the root material has been recorded in the People's Republic of China Pharmacopoeia (2015 edition) and has been listed as one of the eight major anti-SARS medicines.

1.5 Common Forms and Preparations

Indigo naturalis is a dried powder or paste processed from the stems and leaves of Baphicacanthus cusia (Nees) Bremek. (family Acanthaceae), Polygonum tinctorium Ait. (family Polygonaceae), and Isatis indigotica Fort. Indigo naturalis (Qingdai) is a blue powder extracted from the leaves and stems of B. cusia plants using fermentation. Qingdai is extracted from indigo-bearing or indigo-producing plants with a NaOH or KOH aqueous solution and corresponds to a mixture of around 5–15% organic compounds including alkaloids (among which indigo and indirubin are present) and 85–95% inorganic compounds such as calcium carbonate and calcium hydroxide.

The three primary herbal medicines derived from S. cusia (= B. cusia) are distinguished in the Chinese materia medica literature:

• Nan-Ban-Lan-Gen (Rhizoma et Radix Baphicacanthis Cusiae, RRBC) — the root and rhizome, widely used for treatment of many epidemic diseases.
• Malanye (Southern Daqingye) — the stem and leaf, used as an antipyretic-alexipharmic drug, frequently used in southern China.
• Qingdai (Indigo Naturalis) — a processed product, traditionally applied to dermatoses.

Modern dosage forms of Indigo Naturalis include topical ointments, oil extracts (e.g., Lindioil), enema solutions, suppositories, and oral powders or capsules, as documented in clinical studies discussed below.

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2. Traditional and Historical Use

2.1 Historical Timeline

Indigo naturalis was first recorded in the materia medica book "Yao Xing Lun," which was compiled during the Tang dynasty of China, approximately 1,400 years ago. Strobilanthes cusia (= Baphicacanthus cusia) is a traditional Chinese medicinal plant with a long medicinal history of approximately one thousand years. Initially, indigo naturalis was used as a primitive dye in ancient India and then introduced into China through Persia; during the Tang Dynasty, it was also used as a fashionable cosmetic for thrush (oral pigmentation).

2.2 Traditional Chinese Medicine (TCM) Applications

In TCM, Baphicacanthus cusia (also known as Qing Dai or Indigo Naturalis) is valued for its purported ability to clear heat, resolve toxicity, and cool the blood. It has been utilized both topically and orally for various dermatological conditions such as psoriasis, eczema, and other inflammatory skin diseases.

Indigo naturalis has been traditionally used in the treatment of hemoptysis, epistaxis, chest pain, aphtha, and infantile convulsion in China for thousands of years. It has also been widely used for the clinical treatment of colds, fever, and influenza in Traditional Chinese Medicine.

In TCM, Qing Dai is sometimes included in formulations intended to address gastrointestinal symptoms such as ulcers, gastritis, and dysentery, based on its perceived ability to clear heat and dampness from the digestive tract.

Historical TCM texts such as the "Compendium of Materia Medica" (Bencao Gangmu) document topical application for detoxifying the skin, reducing swelling, and promoting healing in cases of ulcers, boils, and various skin lesions. The powdered form of Qing Dai has been traditionally applied directly to affected areas to aid in the drying and resolution of sores.

2.3 Use in the Root Form (Nan-Ban-Lan-Gen)

The root is used as a traditional Chinese medicine named "Nan-Ban-Lan-Gen." The nature and taste of this medicinal material is described as cold and bitter, and its action is understood in TCM as clearing away heat and toxicity in the human body. NBLG exhibits a bitter taste and cold nature, and has traditionally been used to treat sore throat and fever due to its antiviral, anti-inflammatory, and antibacterial properties.

2.4 Use in Laos and Southeast Asia

In Laos, Baphicacanthus cusia is one of the most commonly used indigo-producing plants, and it is indigenous to the Indo-China peninsula, primarily in the north-east, where there is a long tradition of its cultivation and usage. Beyond medicinal applications, the plant is widely cultivated for use as a natural textile dye throughout the region.

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3. Key Chemical Constituents and Active Compounds

3.1 Overview of Chemical Complexity

A total of sixty-three compounds, including indole alkaloids, terpenoids, organic acids, steroids, and nucleosides, have been isolated from indigo naturalis (derived from B. cusia and related plants), of which indole alkaloids are the most important. Indigoid indole alkaloids, quinazolinone alkaloids, monoterpenes, triterpenes, flavonoids, sterols, anthraquinones, benzoxazinones, and lignans have been reported from Baphicacanthus cusia.

In the root preparation (Nan-Ban-Lan-Gen, NBLG) alone, a total of 73 compounds belonging to six classes have been assigned using UHPLC-Q-TOF-MS analysis, with alkaloids being the most abundant and diverse species.

3.2 Principal Bioactive Compounds

The pivotal bioactive compounds in B. cusia are indirubin, indigo, and tryptanthrin. Additionally, isorhamnetin, indigodole A, and indigodole C are responsible for key pharmacological activities.

• Indirubin: Indole alkaloids, particularly indigo and indirubin, are the primary active constituents of B. cusia. Indirubin, isolated from indigo naturalis, was used as a new agent to treat leukemia in China in the 1970s and is also an active ingredient in the treatment of psoriasis. Indigo and indirubin are potent aryl hydrocarbon receptor (AhR) ligands, and indirubin exerts antiproliferative activity on leukocytes and keratinocytes.
• Indigo: Indigo is one of the most famous ancient dyes and is the main component of plants such as Baphicacanthus cusia. Its precursor, indican, undergoes hydrolysis to form indoxyl, which oxidizes to indigo and indirubin.
• Tryptanthrin: The active ingredients of Indigo Naturalis are mainly indigo, indirubin, and tryptanthrin (indolo[2,1-b]quinazoline-6,12-dione). Tryptanthrin has been reported to suppress Th17 polarization and IL-17-induced secretions of pro-inflammatory mediators such as IL-6 and IL-8 by keratinocytes.
• Indican: Leaves contain significantly higher contents of indican than stems and roots — 20,978.26 μg/g in leaves versus 3,056.78 μg/g in stems and 170.45 μg/g in roots, as measured by HPLC-DAD. Indican exhibits antibacterial and antifungal activities.
• Novel bisindole alkaloids: Four pairs of stereoisomeric indole alkaloids — baphicacanthcusines A–D — and one new indole alkaloid, baphicacanthcusine E, were identified from the leaves of B. cusia. Baphicacanthcusines A and B possess an unprecedented skeleton in which two indole moieties are bridged by a phenylpropane unit, while baphicacanthcusine C represents the first natural dispiro-oxazolidinone bisoxindoles.
• Quinazolinone alkaloids: Five neuraminidase inhibitory alkaloids identified from B. cusia include 2,4(1H,3H)-quinazolinedione, 4(3H)-quinazolinone, 2(3H)-benzoxazolone, tryptanthrin, and indirubin.
• Aurantiamide acetate: A peptide derivative, aurantiamide acetate, has been identified as an active compound in extracts of B. cusia root, possessing antioxidant and anti-inflammatory properties.
• Additional constituents: Researchers have identified four stereoisomeric indole alkaloids baphicacanthcusines A–D, and compounds such as 1,3-dihydro-2H-indol-2-one, hispidulin, bungein A, and calendin from the leaves of B. cusia for the first time.

3.3 Biosynthetic Origins

Transcriptome analyses have provided a detailed view of the enzymes involved in indican backbone biosynthesis, such as cytochrome P450, UDP-glycosyltransferase, glucosidase, and tryptophan synthase, with tryptophan synthase identified as the candidate gene involved in the tissue-specific biosynthesis of indican.

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4. Mechanisms of Action

4.1 Aryl Hydrocarbon Receptor (AhR) Pathway

The mechanisms of indigo naturalis for ulcerative colitis are associated with aryl hydrocarbon receptor pathway activation, immune regulation, oxidative stress inhibition, and intestinal microbial modulation. Indirubin and indigo, as potent AhR ligands, are understood to mediate many of the immunomodulatory effects of the plant's preparations through this receptor.

4.2 Cyclin-Dependent Kinase (CDK) Inhibition

Indirubin exhibits inhibitory activity towards cyclin-dependent kinase (CDK) 1–cyclin B with IC50 = 10 μM; its derivatives inhibit CDK1 even more efficiently — indirubin-3′-monoxime with IC50 = 0.18 μM, 5-chloro-indirubin with IC50 = 0.4 μM, and indirubin-5-sulphonic acid with IC50 = 0.055 μM. Indirubin also inhibits cyclin-dependent kinases in tumor cells.

4.3 Anti-inflammatory Signaling Pathways

Multiple studies have shown that indigo, indirubin, and tryptanthrin exhibit excellent anti-inflammatory activities. Tryptanthrin exerts an anti-inflammatory effect on ulcerative colitis by modulating the secretion of inflammatory factors and decreasing the expression of NF-κB p65. Aurantiamide acetate isolated from B. cusia root shows potent anti-viral and anti-inflammatory effects on influenza A virus-infected cells via inhibition of the NF-κB pathway.

4.4 Th17/IL-17 Axis Suppression

The Chinese herbal medicine Qing-Dai (Indigo naturalis) extracted from Baphicacanthus cusia has been previously reported to exhibit anti-psoriatic effects in topical treatment. Th17 cells are a key player in the pathogenesis of psoriasis. Researchers have investigated the anti-Th17 effect of Indigo naturalis and its active compounds. An in vitro study confirmed a direct anti-Th17 effect of both the IN herbal extract and tryptanthrin.

4.5 Antitumor Mechanisms

The potent substances indirubin, indigo, and tryptanthrin, and their derivatives, demonstrate antitumor effects through inducing cell cycle arrest, triggering programmed cell death (apoptosis), inhibiting metastasis, and overcoming multidrug resistance.

4.6 Neuraminidase Inhibition (Antiviral)

Five active alkaloids from B. cusia were identified as neuraminidase inhibitors: 2,4(1H,3H)-quinazolinedione, 4(3H)-quinazolinone, 2(3H)-benzoxazolone, tryptanthrin, and indirubin. These compounds showed pronounced neuraminidase inhibitory activities with IC50 values of 98.98, 64.69, 40.16, 69.44, and 144.73 μM, respectively, in fluorescence-based assays.

4.7 MAPK and STAT3 Pathway Modulation

Influenza A virus infection rapidly triggers activation of innate immunity through phosphorylation of mitogen-activated protein kinases (MAPKs) and STAT proteins. Indirubin derivatives can suppress virus-induced cytokine production through MAPKs and STAT3 signaling pathways, underscoring their immunomodulatory effects on pulmonary endothelium.

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5. Scientific Evidence by Area of Use

5.1 Psoriasis

Traditional Background

Indigo naturalis, extracted from the leaves and branches of Baphicacanthus cusia (Nees) Bremek., has traditionally been used to treat psoriasis.

Preclinical Evidence

In cell-based studies using IL-22-treated HaCaT keratinocytes (a model of psoriatic inflammation), indirubin significantly decreased intracellular reactive oxygen species (ROS) production and lowered the production of ICAM-1, TNF-α, and IL-6. Indirubin, indigo, and tryptanthrin each decreased the proportion of Ki67-positive cells, but only indirubin decreased cells entering the S phase and suppressed expression of cyclin D1 and cyclin E1.

Clinical Evidence

The clinical evidence for topical Indigo Naturalis in psoriasis is among the strongest for any application of this plant. In a randomized, observer-blind, vehicle-controlled trial enrolling 42 outpatients with chronic plaque psoriasis (May 2004 – April 2005), patients applied either indigo naturalis ointment or vehicle ointment topically to bilaterally symmetrical psoriatic plaque lesions for 12 weeks. Significant reductions in the sum of scaling, erythema, and induration scores (P < .001) and plaque area percentage (P < .001) were achieved with topical indigo naturalis ointment (mean score 6.3 after treatment versus 12.8 in controls). Approximately 31 of 42 patients (74%) experienced clearance or near clearance in the indigo naturalis–treated lesion, leading investigators to conclude that topical indigo naturalis ointment was a novel, safe, and effective therapy for plaque-type psoriasis.

A subsequent dose-ranging trial added precision to the optimal formulation: in a randomized, double-blind trial, adult patients with chronic plaque psoriasis for >1 year and with <20% body surface area affected were randomized to apply Lindioil ointment containing 200, 100, 50, or 10 μg/g of indirubin twice daily for 8 weeks, followed by an additional 12-week safety/extension period. The conclusion was that 200 μg/g of indirubin in Lindioil ointment is the most effective concentration studied so far for treating psoriasis topically, and is safe.

A few clinical trials have indicated that topical indigo naturalis ointment is effective for psoriasis and atopic dermatitis.

Evidence strength: Moderate. Multiple randomized controlled trials and observer-blind trials support efficacy of topical indigo naturalis for plaque psoriasis. Trials are relatively small and primarily conducted in Taiwan. Further large-scale, multi-center trials are warranted.

5.2 Ulcerative Colitis (UC)

Traditional Background

While the primary traditional uses of B. cusia have involved dermatological conditions and febrile diseases, there is traditional precedent for its application in treating digestive disorders. In TCM, Qing Dai has been included in formulations for gastrointestinal symptoms such as ulcers, gastritis, and dysentery.

Clinical Evidence

The therapeutic promise of Indigo Naturalis for UC has been proven by numerous preclinical and clinical studies. Indirubin, indigo, isatin, tryptanthrin, and β-sitosterol are considered the key components in the treatment of UC with IN. Both preclinical and clinical studies support the efficacy of IN for UC, especially in severe UC or in those who do not respond to or have poor efficacy with existing therapies.

A pivotal multicenter randomized controlled trial (Naganuma et al., 2018, published in Gastroenterology) is cited extensively in the systematic review literature. The response rates observed were 26.3% (5 of 19 patients) in the placebo group and 82.6% (19 of 23 patients) in the indigo naturalis group, with a statistically significant difference (p = 0.0003), in a multicenter double-blind clinical trial of patients with ulcerative colitis.

Oral Indigo Naturalis induced a clinical response in ulcerative colitis, but one trial was stopped due to a prior case of pulmonary arterial hypertension, possibly related to a self-purchased product.

The mechanisms of IN for UC are associated with aryl hydrocarbon receptor pathway activation, immune regulation, oxidative stress inhibition, and intestinal microbial modulation.

Evidence strength: Moderate-to-promising, but with significant safety caveats. Randomized controlled trial data support efficacy for inducing clinical response in active UC, particularly refractory cases. However, the serious adverse event of pulmonary arterial hypertension requires careful patient monitoring, and evidence bodies note the results remain preliminary pending further confirmatory trials.

5.3 Leukemia (Acute Promyelocytic Leukemia, APL)

Traditional Background

Indirubin, isolated from indigo naturalis, was used as a new agent to treat leukemia in China in the 1970s.

Clinical Evidence

Combining TCM theory and modern pharmacological study, indigo naturalis–containing Chinese medicines, such as Danggui Longhui Wan and the Realgar–Indigo Naturalis Formula (RIF), are clinically administered to treat human leukemia.

The Realgar–Indigo Naturalis formula (RIF) has been proven very effective in treating human acute promyelocytic leukemia (APL). Multicenter clinical trials showed that a complete remission rate of 96.7% to 98% and a 5-year overall survival rate of 86.88% were achieved in APL patients receiving RIF, with moderate adverse effects such as gastrointestinal discomfort and rash.

Regarding cancer treatment more broadly, there is a lack of evidence to support use beyond APL. Case reports and initial analyses suggest possible benefits in leukemia, but well-designed clinical trials are needed to confirm safety and effectiveness for other cancer types.

Evidence strength: Moderately strong for APL within the context of the RIF formula — multicenter clinical trial data are available. However, RIF is a multi-ingredient formula; the independent contribution of B. cusia-derived indigo naturalis within it cannot be fully isolated. For other malignancies, evidence is limited to preclinical and in vitro data.

5.4 Antiviral Activity (Influenza)

Preclinical Evidence

The root of Baphicacanthus cusia (Nan Ban Lan Gen) has been traditionally used to prevent and treat influenza A virus infections, and the peptide derivative aurantiamide acetate has been identified as an active antiviral compound in root extracts. Indirubin derivatives have been shown in primary cell culture models to delay virus replication, leading investigators to conclude that indirubin derivatives have potential to be used as an adjunct to antiviral therapy for severe human H5N1 disease.

Given the established significance of neuraminidase as a critical target in influenza virus replication, alkaloids extracted from the stems and leaves of B. cusia have been evaluated for neuraminidase inhibitory activity to assess their potential therapeutic efficacy against influenza.

Evidence strength: Preclinical and in vitro only. No human clinical trials have established B. cusia–derived preparations as a proven antiviral therapy for influenza or other viral infections. The traditional use is well documented, but clinical validation is lacking.

5.5 Anti-inflammatory and Other Applications

Modern research has found that indigo naturalis can be used to treat liver injury, nephritis, mouth ulcers, and other skin diseases, which may be related to its anti-inflammatory, antioxidant, and immunoregulatory effects. However, research of these conditions mostly remains at the basic research stage, and more clinical data are needed.

A small study in patients with head and neck cancer suggests that indirubin, taken as indigowood root powder, may reduce mucosal damage from radiation therapy, but additional studies are needed to confirm this effect.

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6. Body Systems and Health Areas

Modern pharmacological studies have revealed that B. cusia has numerous bioactive properties relevant to multiple body systems, including antitumor, antiviral, anti-inflammatory, antioxidant, hepatoprotective, and neuroprotective activities. The body systems specifically associated with documented research include:

• Integumentary (skin) system: Psoriasis, eczema/atopic dermatitis, contact dermatitis, oral ulcers, skin infections, wound healing. Indigo naturalis has anti-inflammatory, anti-bacterial, and antioxidant effects, and has been used to treat a wide range of inflammatory skin conditions, including psoriasis and contact dermatitis.
• Gastrointestinal system: Ulcerative colitis, proctitis, dysentery, gastric ulcers. Due to its excellent anti-inflammatory effects, indigo naturalis is clinically used to treat ulcerative colitis (UC), acute promyelocytic leukemia, and psoriasis.
• Hematopoietic / oncological system: Acute promyelocytic leukemia, chronic myelogenous leukemia. Indigo naturalis is utilized in the treatment of a diverse array of diseases including ulcerative colitis, psoriasis, oral ulcers, radiation proctitis, chronic myelocytic leukemia, and herpes zoster.
• Immune system: Immunomodulatory activity via AhR signaling, Th17 suppression, and modulation of cytokine production.
• Respiratory system: Traditional use for cough, hemoptysis, colds, and influenza.

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7. Dosage Forms and Reported Dosages

The following dosages are reported as they appear in cited scientific sources and should not be interpreted as clinical recommendations.

Topical (Skin Psoriasis)

• In a randomized double-blind trial, Lindioil ointment containing 200, 100, 50, or 10 μg/g of indirubin was applied twice daily for 8 weeks, followed by a 12-week safety/extension period, in adult patients with chronic plaque psoriasis covering <20% body surface area.
• 200 μg/g of indirubin in Lindioil ointment was the most effective concentration studied in this trial.
• In an earlier randomized trial, indigo naturalis ointment or vehicle ointment was applied topically to bilateral psoriatic plaque lesions for 12 weeks.

Oral (Ulcerative Colitis)

• In a randomized controlled trial, oral indigo naturalis therapy was administered for 8 weeks to patients with moderate to severe ulcerative colitis.
• The Naganuma et al. (2018) multicenter RCT (published in Gastroenterology, volume 154) is cited in multiple systematic reviews as a key source of evidence for oral dosing in UC.

Composition of Prepared Qingdai

• Qingdai as prepared corresponds to a mixture of around 5–15% organic compounds (including indigo and indirubin alkaloids) and 85–95% inorganic compounds (such as calcium carbonate and calcium hydroxide).

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8. Safety Considerations and Adverse Events

The safety profile of Baphicacanthus cusia preparations differs substantially depending on the route of administration (topical versus oral) and the form used.

8.1 Topical Use

Although the clinical efficacy of indigo naturalis has been confirmed, adverse events (AEs) associated with indigo naturalis should not be ignored. Adverse reactions for external (topical) use are minor and mainly occur through oral administration. Cosmetic staining due to the deep blue pigment of indigo is an expected consequence of topical use; refined oil-extract formulations (Lindioil) were developed in part to address this.

8.2 Oral Use — Adverse Events

AEs categorized for oral indigo naturalis include mild AEs, such as liver dysfunction, renal dysfunction, headache, gastrointestinal symptoms, and nausea, and severe AEs, such as acute colitis, colonic intussusception, and pulmonary arterial hypertension (PAH).

In a national survey in Japan, of 877 patients with UC who received indigo naturalis treatment, 91 experienced adverse events (liver dysfunction, gastrointestinal symptoms, headache, pulmonary arterial hypertension, and intussusception), including 21 patients who reported gastrointestinal symptoms such as nausea and epigastralgia.

The common adverse effects associated with indigo naturalis include liver dysfunction, headaches, abdominal pain, and nausea. Notably, case reports have documented instances of ischemic injury to the colorectal mucosa attributed to indigo naturalis.

8.3 Pulmonary Arterial Hypertension (PAH) — A Specific Concern

The clinical use of indigo naturalis carries the risk of adverse events including pulmonary hypertension, which requires its rational and monitored application. Liver dysfunction observed has been described as mildly reversible. After stopping treatment, pulmonary hypertension has been reported to resolve without any deaths in published case series.

8.4 Gastrointestinal Structure — Intussusception and Colitis

In documented case series, surgery was required in approximately 40% of patients with intestinal adhesions related to indigo naturalis treatment. Acute colitis and colonic intussusception are listed among the severe adverse event categories identified in surveillance data.

8.5 Long-Term Monitoring

Although indigo naturalis has some side effects in the treatment of UC, it is still considered a potential drug. It is necessary to monitor adverse reactions during long-term use.

8.6 Adulteration and Quality Control

Nan-Ban-Lan-Gen (NBLG), derived from the root and rhizome of Baphicacanthus cusia, was initially included in the Chinese Pharmacopoeia as one of multiple resources of Ban-Lan-Gen, together with the roots of Isatis indigotica Fort. (Bei-Ban-Lan-Gen, BBLG). Evidence from studies on plant sources, chemical and pharmacological properties has revealed notable differences between NBLG and BBLG. This distinction is pharmacopoeially and clinically relevant because the two roots have overlapping names but distinct chemical compositions and properties.

8.7 Memorial Sloan Kettering Cancer Center (MSKCC) Summary

Oral indigo naturalis has been used in clinical trials in Asia for ulcerative colitis and other gastrointestinal conditions, but results are preliminary and severe adverse events have been reported.

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9. Summary of Evidence Strength by Indication

• Topical psoriasis (plaque type): Moderate — multiple small to moderate RCTs, consistent positive results, limited external validity due to geographic concentration of research.
• Ulcerative colitis (oral): Moderate — multicenter RCT data available (Naganuma et al., 2018); tempered by serious adverse event signal (PAH, intussusception); ongoing monitoring required.
• Acute promyelocytic leukemia (RIF formula): Moderate (as part of a multi-ingredient formula) — multicenter clinical data with high remission rates; independent contribution of B. cusia constituent remains incompletely characterized.
• Antiviral (influenza, SARS): Weak — in vitro and traditional use data only; no validated clinical trials.
• Other skin diseases, mouth ulcers, liver injury: Very weak — basic research stage, clinical data insufficient.

References

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