Qing Dai
StarBaphicacanthus cusia (Nees) Bremek.
Traditionally used for
- Nose & throat
- Cough & breathing
- Colds & fever
- Nerves & recovery
- Skin
Cautions & contraindications
- Liver conditions
☯ TCM Properties
Clears Heat and Resolves Toxicity; Cools the Blood and Resolves Macules; Clears Liver Fire; Calms fright and stops convulsions; Clears Lung Heat
Traditional Chinese Uses
Qing Dai (natural indigo powder) is derived from several indigo-bearing plants and possesses a strongly cold, intensely Heat-clearing character. It excels at resolving Fire toxin patterns — including high fever with convulsions, swollen and painful throat, and bleeding conditions from Heat entering the Blood level. Applied topically, it treats hot, inflamed, or ulcerated skin sores. Modern clinical use in Chinese medicine also includes certain inflammatory conditions and some types of leukemia, under professional supervision.
Western Herbalism Properties
Pharmacological Effects
- Antineoplastic: Indirubin moderately inhibited transplanted tumours: 200 mg/kg s.c./i.p. x6 days inhibited rat W256 carcinoma 47-52%/50-58%; oral 500 mg/kg less active; inhibited Lewis lung carcinoma 43% but not murine leukemias L7212, P388, L1210. Acts mainly by inhibiting DNA synthesis; may complex with DNA and DNA polymerase; affects CML cell membranes.
- Immunomodulatory: Long-term indirubin treatment normalized cellular immunity and restored depressed humoral immunity in patients.
- Other: Decoction antibacterial in vitro; oral indigo 0.3-3 g/kg for 8 days protected mice from CCl4 hepatotoxicity.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 187.
Relationships
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Botanical Description
Baphicacanthus cusia (syn. Strobilanthes cusia), Assam indigo or Chinese rain bell, is a perennial herb in the Acanthaceae family, growing 0.5-1 m tall with quadrangular, swollen-jointed stems that often root at the nodes. The leaves are opposite, elliptic to lanceolate, 10-25 cm long, with serrate margins and a pointed apex; they turn dark blue-black on bruising or drying due to indican oxidation. Flowers are tubular, pale violet to pink, borne in short terminal or axillary spikes subtended by leafy bracts. The fruit is a small club-shaped capsule containing four seeds. Qing Dai is the dark blue-violet pigment-rich powder prepared by fermenting and lime-treating the leaves and stems, then collecting the floating indigotin-rich froth (POWO; Wikipedia).
Active Constituents
Indigo (indigotin)
Bis-indole pigmentConcentration: highly variable between batches; surveyed values span roughly 0.25% to 30% of the processed drug, and the Chinese Pharmacopoeia sets a minimum of 2.0%
The blue pigment that gives the drug its name. It is a ligand for the aryl hydrocarbon receptor and, with indirubin, accounts for the AhR-dependent induction of interleukin 22 and mucosal regeneration proposed as the mechanism in ulcerative colitis. The enormous batch-to-batch range is itself a clinical problem: the label dose of Qing Dai does not fix the dose of active pigment.
Indirubin
Bis-indole alkaloid (red isomer of indigo)Concentration: roughly 0.08% to 3.7% of the processed drug across surveyed batches; Chinese Pharmacopoeia minimum 0.13%
The most pharmacologically studied constituent. It is a potent aryl hydrocarbon receptor ligand and a cyclin-dependent kinase inhibitor, and it suppresses keratinocyte proliferation and inflammation, which is the basis of the topical psoriasis work. It is metabolised by CYP1A1, CYP1A2 and CYP1B1 and also induces those enzymes.
Tryptanthrin
Indoloquinazoline alkaloidConcentration: very variable; reported around 0.7% in one analysis and at trace levels (of the order of 0.0001%) in others
An antimicrobial and antiviral constituent isolated from Strobilanthes cusia leaf, where it inhibits human coronavirus NL63 replication in cell culture. It was first isolated from this species in 1979 as an antifungal principle.
Isatin
OxindoleA minor indole constituent of the processed drug, formed during the fermentation and oxidation of the indican precursor in the leaf.
Qingdainone
Indole alkaloidA minor alkaloid first characterised in 1985 and named after the drug; reported to have antimelanoma activity in laboratory assays. It is not a marker used for quality control.
Calcium carbonate
Inorganic mineral matterConcentration: reported between 59% and 96% of the finished drug depending on the preparation method
Not a therapeutic constituent but the bulk of the material. Qing Dai is prepared by precipitating the indigo pigments with lime, so most of a gram of Qing Dai is inorganic carrier plus silica. This is why gram doses of the drug deliver only tens of milligrams of indigo and indirubin, and why batch quality varies so widely.
⚠ Drug Interactions
CYP1A2 substrates (theophylline, clozapine, olanzapine, tizanidine, caffeine)
Indirubin and indigo are potent aryl hydrocarbon receptor ligands and induce microsomal CYP1A1 and CYP1A2 activity in mouse liver; the induction is abolished in AhR knockout mice, confirming it is receptor-mediated (Sugihara 2004). AhR activation is also the mechanism the ulcerative colitis trials invoke for the drug's benefit, so induction is not an incidental property but part of how it works. Human interaction studies have not been done, and indirubin also induces the enzymes that clear it, so the magnitude in patients is unknown.
Clinical note: Treat as you would any CYP1A2 inducer: check levels or clinical response for narrow-index CYP1A2 substrates such as theophylline and clozapine when Qing Dai is started or stopped, rather than assuming a herbal product is inert.
Hepatotoxic drugs and drugs requiring liver function monitoring (methotrexate, azathioprine, isoniazid, paracetamol at high dose)
In a Japanese nationwide survey of 877 ulcerative colitis patients using indigo naturalis, adverse events were reported in 91 patients (107 events) and liver dysfunction was the largest category (n = 40). It occurred even at 0.5 g daily, showed no dose-effect relationship, and was generally mild and reversible. Stacking that background risk on a drug with its own hepatotoxicity removes the ability to attribute a rising transaminase to either agent.
Clinical note: Obtain baseline liver function tests before use alongside any hepatotoxic drug and repeat them within the first weeks. Do not attribute a transaminase rise to the prescription drug without considering the herb.
Drugs associated with pulmonary arterial hypertension (dasatinib, interferons, anorectic agents)
Pulmonary arterial hypertension occurred in 11 of the 877 surveyed indigo naturalis users, and it was a report of PAH in a patient self-medicating with the drug for six months that caused the INDIGO randomised trial to be terminated early. Reported cases have improved on withdrawal, in one published case from a mean pulmonary artery pressure of 72 mmHg to 18 mmHg. A proposed mechanism is nitric oxide synthase inhibition and pulmonary artery endothelial dysfunction. Combining it with a drug that independently causes PAH has not been studied, but there is no reason to expect the risks to be anything other than additive.
Clinical note: Take new exertional breathlessness in anyone taking Qing Dai seriously and investigate for pulmonary hypertension rather than attributing it to anaemia or deconditioning. Avoid the combination with drugs that carry their own PAH signal.
Prescribed ulcerative colitis therapy (mesalazine, thiopurines, biologics)
Indigo naturalis has genuine efficacy in ulcerative colitis, which is exactly why patients buy it themselves. In the 8-week INDIGO randomised trial, clinical response rates were 13.6% on placebo against 69.6%, 75.0% and 81.0% at 0.5, 1.0 and 2.0 g daily. The same literature reports ten cases of intussusception in the Japanese survey, 40% of which needed surgical resection, plus a published case of indigo-naturalis-induced ischaemic colitis. Those events mimic a colitis flare, so a clinician unaware of the herb may escalate immunosuppression in response to a drug-induced lesion.
Clinical note: Ask ulcerative colitis patients directly whether they take Qing Dai or indigo naturalis, including self-purchased product. The INDIGO investigators explicitly concluded it should not yet be used outside trials because of the adverse-effect profile.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction, or powder/pills | 1–3 g | Daily | — | — | 中国药典 2020 【用法与用量】1～3g，宜入丸散用。外用适量。 【性味与归经】咸，寒。归肝经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Cooling liver fire combines with clearing the lung and transforming hot phlegm, so the combination treats liver fire scorching the lung.
For cough with thick yellow sticky phlegm or blood-streaked sputum, chest and hypochondriac pain, and irritability from liver fire invading the lung.
Core pair of a classical formula — Dai Ge San, Wei Sheng Hong Bao (also attributed to Yi Shuo)
Evidence Tier
Moderate evidence · 4 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
2
2 verified · 0 unverified
Other clinical trial
0
Observational / case report
1
0 verified · 1 unverified
In vitro / animal
1
0 verified · 1 unverified
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Efficacy of Indigo Naturalis in a Multicenter Randomized Controlled Trial of Patients With Ulcerative Colitis
Multicentre double-blind trial in 86 Japanese patients with active ulcerative colitis, randomised to 0.5, 1.0 or 2.0 g of indigo naturalis daily or placebo for 8 weeks. Clinical response at week 8 rose dose-dependently: 13.6% on placebo versus 69.6%, 75.0% and 81.0% on the three doses. Remission was 4.5% on placebo versus 55.0% at 1.0 g and 38.1% at 2.0 g, and mucosal healing 13.6% versus 47.6-60.0%. The trial was stopped early after an external report of pulmonary arterial hypertension in a patient using self-purchased indigo naturalis, and mild liver dysfunction occurred in 10 treated patients. The authors concluded the drug should not yet be used because of the potential for adverse effects.
Adverse events in patients with ulcerative colitis treated with indigo naturalis: a Japanese nationwide survey
Questionnaire survey across 337 Japanese institutions identified 49,320 ulcerative colitis patients, of whom 877 (1.8%) had used indigo naturalis. Adverse events were reported in 91 patients (107 events): liver dysfunction 40, gastrointestinal symptoms 21, headache 13 and pulmonary arterial hypertension 11. Ten cases of intussusception were reported and 40% of those patients required surgical resection. No dose-effect relationship was found, liver dysfunction tended to be mild and reversible, and PAH recovered on withdrawal. No deaths were reported.
Clinical Assessment of Patients With Recalcitrant Psoriasis in a Randomized, Observer-Blind, Vehicle-Controlled Trial Using Indigo Naturalis
Randomised, observer-blind, vehicle-controlled intrapatient trial of topical indigo naturalis ointment in recalcitrant plaque psoriasis. The summed scaling, erythema and induration score fell to a mean of 6.3 in treated lesions against 12.8 in control lesions, and involved plaque area to 38.5% against 90%. Thirty-one of 42 patients (74%) achieved clearance or near-clearance of the treated lesion. This is topical use of the processed drug on skin, and it says nothing about the safety of swallowing it.
Antiviral Action of Tryptanthrin Isolated from Strobilanthes cusia Leaf against Human Coronavirus NL63
Cell-culture study using extract of Strobilanthes cusia (the accepted synonym of Baphicacanthus cusia) leaf, the same plant material from which Qing Dai is prepared. Tryptanthrin was the most active isolated constituent against human coronavirus NL63, inhibiting viral replication and papain-like protease 2 activity. This is a laboratory result on a leaf extract, not on the processed indigo drug, and not a clinical finding.
⚠ Safety & Contraindications
- Liver conditions
Contraindications
Its use is cautious in patients with stomach cold.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 53–72.
Side Effects
- Oral Qing Dai: abdominal pain, diarrhea, nausea, vomiting, mushy stool
- Indirubin: GI irritation incl. nausea, vomiting, abdominal pain, diarrhea, bloody stool; thrombocytopenia from bone marrow inhibition
- Oral indirubin 80 mg/kg daily for 1-3 months caused anorexia and diarrhea in rats; dogs more sensitive to indirubin toxicity
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 187.
Historical Texts
Yao Xing Lun
Tang dynastyKai Bao Ben Cao
Song dynastyBen Cao Gang Mu
Ming dynastyReferences
- Sun Q, Leng J, Tang L, Wang L, Fu C. A Comprehensive Review of the Chemistry, Pharmacokinetics, Pharmacology, Clinical Applications, Adverse Events, and Quality Control of Indigo Naturalis . Frontiers in Pharmacology (2021) [DOI]
- Sugihara K, Kitamura S, Yamada T, Okayama T, Ohta S, Yamashita K, Yasuda M, Fujii-Kuriyama Y, Saeki K, Matsui S, Matsuda T. Aryl hydrocarbon receptor-mediated induction of microsomal drug-metabolizing enzyme activity by indirubin and indigo . Biochemical and Biophysical Research Communications (2004) [DOI]
- Adachi S, Nakano Y, Kondo T. Risk of Pulmonary Arterial Hypertension During Qing-Dai Use for the Treatment of Ulcerative Colitis . Circulation Journal (2020) [DOI]
- Cho B, Yoon SM, Son SM, Kim HW, Kim KB, Youn SJ. Ischemic colitis induced by indigo naturalis in a patient with ulcerative colitis: a case report . BMC Gastroenterology (2020) [DOI]
- Uchiyama K, Takami S, Suzuki H, Umeki K, Mochizuki S, Kakinoki N, Iwamoto J, Hoshino Y, Omori J, Fujimori S, Yanaka A, Mizokami Y, Ohkusa T. Efficacy and safety of short-term therapy with indigo naturalis for ulcerative colitis: An investigator-initiated multicenter double-blind clinical trial . PLOS ONE (2020) [DOI]
- Lin YK, See LC, Huang YH, Chang YC, Tsou TC, Lin TY, Lin NL. Efficacy and safety of Indigo naturalis extract in oil (Lindioil) in treating nail psoriasis: A randomized, observer-blind, vehicle-controlled trial . Phytomedicine (2014) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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