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PubMed · Strobilanthes cusia (Nees) Kuntze, a multifunctional traditional Chinese medicinal plant, and its herbal medicines: A comprehensive review. (2021)
PubMed · Indigodole E from <i>Strobilanthes cusia</i> exhibits anti-IL-17A effect. (2022)
Reviewed by: HerbAlly Editorial Team, Medical herbalists and healthcare professionals
This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.
Compiled from 30 PubMed articles · model: gemma4:31b
Summary
Indigo naturalis (Qing dai) is a traditional herbal medicine derived from plants such as Strobilanthes cusia, used primarily for autoimmune conditions like psoriasis and ulcerative colitis [PMID:38301993].
Background
Indigo naturalis is a dried powder derived from plants including Baphicacanthus cusia (Strobilanthes cusia), Polygonum tinctorium Ait., and Isatis indigotica Fork [PMID:38301993]. It is a processed product of S. cusia, a traditional Chinese medicinal plant [PMID:32889034].
Traditional uses
Historically used as a dye in ancient India, Egypt, Africa, and China [PMID:38301993]. In traditional medicine, it has been used for hemoptysis, epistaxis, chest discomfort, aphtha [PMID:38301993], and for clearing heat, detoxifying blood, eliminating spots, and reducing fire [PMID:35872288].
Active compounds
Main active components include indigo, indirubin, tryptanthrin [PMID:39316667, PMID:38948310], and isatin [PMID:38948310]. Other isolated compounds include indazole alkaloids such as indigodoles A, C, and E [PMID:35192387, PMID:30852259].
Mechanism of action
In psoriasis, it regulates keratinocyte proliferation and differentiation, restores epidermal barrier function, and reduces inflammatory processes [PMID:26954317]. Specific compounds like indigodole E, indigodole C, and tryptanthrin inhibit IL-17A protein production or gene expression [PMID:35192387, PMID:30852259]. In inflammatory bowel disease (IBD), mechanisms include activation of the Aryl hydrocarbon Receptor (AhR) pathway, inhibition of the NF-κB/NLRP3/IL-1β pathway, and modulation of the TLR4/MYD88/NF-κB pathway [PMID:38948310]. Indirubin may exert effects via PI3K/AKT/mTOR, MAPK, and JAK/STAT3 pathways [PMID:35598366].
Clinical evidence
Evidence AUlcerative Colitis
Pooled clinical response rate was 0.796 and clinical remission rate was 0.668; clinical response rates were significantly higher compared to placebo (RR 3.70) [PMID:38006941, PMID:38612967].
Evidence CPsoriasis
Chinese herbal medicine formula groups showed a higher response rate for PASI60 compared to control groups [PMID:39316667].
Evidence DPediatric Ulcerative Colitis
In a survey of 107 patients, 80.2% achieved clinical remission within 6 months [PMID:35831249].
Evidence CAcute Promyelocytic Leukemia (APL)
Oral Realgar-Indigo Naturalis formula (RIF) plus all-trans-retinoic acid (ATRA) displays high efficacy and allows for home-based postremission therapy [PMID:33614484].
Safety & adverse effects
Long-term consumption is associated with adverse effects [PMID:38301993]. Reported severe complications include indigo naturalis-induced colitis [PMID:29964335, PMID:31034341] and pulmonary arterial hypertension (PAH) [PMID:41403416, PMID:31034341]. Indirubin has been linked to hepatic injury in mice with chronic colitis, mediated by macrophage transport of insoluble aggregates to the liver [PMID:40546113].
Evidence summary
Strong evidence (Meta-analyses) supports efficacy for ulcerative colitis. Evidence for psoriasis and leukemia is primarily based on reviews and smaller studies. Significant safety concerns exist regarding long-term use, specifically PAH and colitis.
PubMed sources
1.PMID: 40210174 (2025) — Herbal medicine for treating psoriasis: A systematic review. · Complementary therapies in medicine
2.PMID: 29964335 (2018) — Indigo naturalis-induced colitis. · Digestive endoscopy : official journal of the Japan Gastroenterological Endoscopy Society
3.PMID: 38006941 (2024) — Indigo naturalis (Qing dai) for inflammatory bowel disease: A systematic review and meta-analysis. · Clinics and research in hepatology and gastroenterology
4.PMID: 35872288 (2022) — Psoriasis treatment using Indigo Naturalis: Progress and strategy. · Journal of ethnopharmacology
5.PMID: 35192387 (2022) — Indigodole E from Strobilanthes cusia exhibits anti-IL-17A effect.
Government sources
No direct government monograph is available for this herb. The content below is AI-generated and has not been verified against an authoritative government source. Use the search links to check official sources before relying on this information.
6.PMID: 38301993 (2024) — The double-edged sword effect of indigo naturalis. · Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association
7.PMID: 41403416 (2025) — Long-term outcomes of Qing-Dai-induced pulmonary arterial hypertension. · ERJ open research
9.PMID: 33614484 (2020) — Oral Realgar-Indigo Naturalis Formula Plus Retinoic Acid for Acute Promyelocytic Leukemia. · Frontiers in oncology
10.PMID: 15612772 (2004) — Formation of natural indigo derived from woad (Isatis tinctoria L.) in relation to product purity. · Journal of agricultural and food chemistry
11.PMID: 26954317 (2016) — A Review of Indigo Naturalis as an Alternative Treatment for Nail Psoriasis. · Journal of drugs in dermatology : JDD
12.PMID: 38948310 (2024) — Indigo Naturalis in Inflammatory Bowel Disease: mechanisms of action and insights from clinical trials. · Journal of pharmacopuncture
13.PMID: 37904107 (2023) — Identification of novel flavin-dependent monooxygenase from Strobilanthes Cusia reveals molecular basis of indoles' biosynthetic logic. · BMC plant biology
14.PMID: 32889034 (2021) — Strobilanthes cusia (Nees) Kuntze, a multifunctional traditional Chinese medicinal plant, and its herbal medicines: A comprehensive review. · Journal of ethnopharmacology
15.PMID: 33317592 (2020) — From natural dye to herbal medicine: a systematic review of chemical constituents, pharmacological effects and clinical applications of indigo naturalis. · Chinese medicine
16.PMID: 31034341 (2019) — Treatment with indigo naturalis for inflammatory bowel disease and other immune diseases. · Immunological medicine
17.PMID: 35831249 (2022) — Qing-Dai for pediatric ulcerative colitis multicenter survey and systematic review. · Pediatrics international : official journal of the Japan Pediatric Society
18.PMID: 37669429 (2023) — High-Quality Indigo Naturalis Obtained with Automatic Foam Separation. · ACS applied materials & interfaces
19.PMID: 32981147 (2020) — Blue genome: chromosome-scale genome reveals the evolutionary and molecular basis of indigo biosynthesis in Strobilanthes cusia. · The Plant journal : for cell and molecular biology
20.PMID: 39316667 (2024) — Evidence and potential mechanism of action of indigo naturalis and its active components in the treatment of psoriasis. · Annals of medicine
21.PMID: 39154058 (2024) — Complementary and Alternative Therapies for Psoriasis. · Archives of dermatological research
22.PMID: 40756994 (2025) — Indigo naturalis for inflammatory bowel disease: evidence from animal studies and molecular mechanisms. · Frontiers in pharmacology
23.PMID: 40546113 (2025) — Macrophage-Mediated Transport of Insoluble Indirubin Induces Hepatic Injury During Intestinal Inflammation. · Advanced science (Weinheim, Baden-Wurttemberg, Germany)
24.PMID: 38612967 (2024) — Herbal Medicines for the Treatment of Active Ulcerative Colitis: A Systematic Review and Meta-Analysis. · Nutrients
25.PMID: 35598366 (2022) — Pharmacological properties of indirubin and its derivatives. · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie
26.PMID: 32237505 (2020) — [Advances in biosynthesis of indigo in plants]. · Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica
27.PMID: 30852259 (2019) — Indole alkaloids indigodoles A-C from aerial parts of Strobilanthes cusia in the traditional Chinese medicine Qing Dai have anti-IL-17 properties. · Phytochemistry
28.PMID: 36046107 (2022) — The complete chloroplast genome of Strobilanthes crispus (Acanthaceae). · Mitochondrial DNA. Part B, Resources
29.PMID: 37773314 (2024) — Phytochemical and Pharmacological Properties of a Traditional Herb, Strobilanthes Cusia (Nees) Kuntze. · Molecular biotechnology
30.PMID: 36678602 (2023) — Combining the In Silico and In Vitro Assays to Identify Strobilanthes cusia Kuntze Bioactives against Penicillin-Resistant Streptococcus pneumoniae. · Pharmaceuticals (Basel, Switzerland)