Assam indigo

Assam Indigo (Strobilanthes cusia): A Comprehensive Reference

1. Identity and Botanical Classification

Scientific and Common Names

Strobilanthes cusia (Nees) Kuntze, commonly known as Assam indigo or Chinese rain bell, is a perennial flowering plant of the family Acanthaceae. The accepted scientific name follows the combination Strobilanthes cusia (Nees) Kuntze, where the species was originally described by Nees and later transferred to the genus Strobilanthes by Kuntze. Synonyms include Goldfussia cusia Nees (1832), Ruellia indigofera Griff. (1847), and Strobilanthes flaccidifolia Nees (1847), among others. The plant is also known in Chinese medicine as Malan, and within ethnobotanical literature it appears under the Assamese name rum and the Chinese names bǎn lán and mǎ lán.

Botanical Description and Geographic Range

Strobilanthes cusia is a herbaceous, perennial plant producing a cluster of erect, branched stems that can become more or less woody, at least near the base; it can grow 50–150 cm tall. The species is distributed in Bangladesh, Bhutan, China (Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Sichuan, Taiwan, Xizang, Yunnan and Zhejiang), Laos, Myanmar, North-eastern India, Thailand, and Vietnam, where it grows in humid forests up to about 1,500 m of altitude.

Common Dosage Forms and Preparations

Strobilanthes cusia (SCK) is a traditional Chinese medicinal plant with a long medicinal history of about one thousand years. Through traditional crafts, SCK can be processed into three frequently used herbal medicines. These are:

• Southern Banlangen (Rhizoma et Radix Baphicacanthis Cusiae, RRBC): the root and rhizome of SCK, widely used for treatment of many epidemic diseases.
• Malanye (Southern Daqingye): stem and leaf of SCK, an antipyretic-alexipharmic drug frequently used in southern China.
• Qingdai (Indigo Naturalis, IN): a processed product of SCK, always applied to dermatoses in the folk.

Indigo naturalis (IN), also called "Qingdai" in Chinese, is a dark blue powder, mass, or particle made from the leaf or stem of Strobilanthes cusia (Nees) Kuntze, Persicaria tinctoria (Aiton) Spach, and Isatis tinctoria L. Qingdai 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 leaf and stem extract of S. cusia is one of the sources of Qingdai, which was first recorded in Kaibao Bencao in the Tang dynasty, and Nanbanlangen, the rhizome et radix of S. cusia, was first recorded in Sheng Nong's herbal classic for medicinal purposes. Both are still officially included in the Chinese Pharmacopoeia.

In modern preparations, Indigo Naturalis is available as powder, capsules, and topical ointments. The Chinese Pharmacopoeia stipulates that the mass fractions of indigo and indirubin in Qingdai should be higher than 2.0% and 0.13%, respectively, and indigo and indirubin are used as the criteria for identifying Nanbanlangen.

2. Traditional and Historical Use

Traditional Chinese Medicine (TCM)

In TCM, Strobilanthes cusia has long been applied to detoxification, defervescence, detumescence, and antiphlogosis. Indigo naturalis, derived from indigo plants including Strobilanthes cusia, has been traditionally used in the treatment of hemoptysis, epistaxis, chest pain, aphtha, and infantile convulsion in China for thousands of years.

The leaf of Strobilanthes cusia, popularly known as Da-Ching-Yeh, has been commonly used in traditional Chinese medicine. It is used for influenza, epidemic cerebrospinal meningitis, encephalitis B, viral pneumonia, and mumps. It is also used to treat sore throat, aphthae, and inflammatory diseases with redness of skin.

The root and rhizome, known as Rhizoma et Radix Baphicacanthis Cusiae (RRBC), is an important common medicine, famous for its obvious effects on cold with fever, influenza, mumps, epidemic encephalitis B, and some other infectious diseases. Its leaf and stem, Malanye, is widely used as an antipyretic-alexipharmic drug in the folk. The processed product of its leaf and stem, Indigo Naturalis, is a multifunctional herbal medicine with great therapeutic effects on inflammations, dermatoses, scald, and even hemorrhage.

Traditional Use in Southeast Asia and India

Strobilanthes cusia is grown in India, Myanmar, Thailand, and China and is used in treatment of influenza, cerebrospinal meningitis, encephalitis B, viral pneumonia, mumps, and acute respiratory syndrome.

The leaves possess antibacterial, antifebrile, antioestrogenic, antiprogestogenic, astringent, diuretic, lithotriptic, and uterostimulant properties. A decoction is used in treating menorrhagia, metrorrhagia, sore throat, gingivitis, and fever.

Dye Production and Textile Traditions

Native to South Asia, China, and Indochina, Strobilanthes cusia was historically cultivated on a large scale in India and China as a source of indigo dye, also known as Assam indigo. The leaves contain 0.4–1.3% indican, which can be hydrolyzed and oxidized to produce the classic blue indigo dye. To extract the color, the leaves are fermented in water until they release a vibrant blue pigment, which is then used to create the iconic "Banh Lan" indigo cloth of the Hmong and Miao peoples.

The Landian Yao, part of the Hmong-Mien language family distributed across Southwest and Southern China, Laos, Thailand, and Vietnam, cultivated S. cusia, known as Assam indigo or Chinese rain bell, whose indigo-colored leaves were the main source of high indigotin (a natural blue pigment) for clothing dye.

3. Key Constituents and Active Compounds

Indole Alkaloids

A total of sixty-three compounds, including indole alkaloids, terpenoids, organic acids, steroids, and nucleosides, have been isolated from Indigo Naturalis, of which indole alkaloids are the most important. Phytochemical analyses showed that S. cusia can produce high quantities of biologically active compounds, such as indole alkaloids (IAs), quinolone alkaloids, phenylethanoid glycosides, lignan glycosides, triterpenoids, steroids, amino acids, and flavonoids.

Among these chemical components, indigo and indirubin are the major medicinal ingredients and are isomers of each other (C₁₆H₁₀N₂O₂).

The principal quantified organic constituents include:

• Indigo (indigotin) — the dominant blue pigment; contributes to anti-inflammatory and mucosal-healing activity.
• Indirubin — a red isomer of indigo; prominent anticancer and anti-inflammatory agent.
• Tryptanthrin, isatin, indoxyl β-D-glucoside, indole, indole-3-aldehyde, anthranilic acid, β-sitosterol, betulin, daucosterol, and isorhamnetin, as well as two inorganic compounds, calcium carbonate and silica, have been quantified by different research groups.

The methanol extract of S. cusia leaf contains chemical components such as β-sitosterol, indirubin, tryptanthrin, betulin, indigodole A, and indigodole B, all with diverse biological activities.

Tryptanthrin

Tryptanthrin is a natural indolo-quinazoline alkaloid primarily isolated from S. cusia and has been reported for its strong cytotoxicity against tumor and microbial cells. Tryptanthrin has a variety of pharmacological properties, such as antifungal (dermatophytes), antibacterial (Helicobacter pylori), anti-inflammatory, and antitumor (leukemia, breast, and colon cancer cells) properties.

Mechanisms of Action

Aryl Hydrocarbon Receptor (AhR) Pathway: The two main organic constituents in Indigo Naturalis, indigo and indirubin, are potent AhR agonists. AhR activation may be effective in UC by regulating the immune response and promoting mucosal healing in the intestinal microenvironment, through influences on immune cells, intestinal epithelial cells, endothelial cells, and the enteric nervous system; 8 weeks of treatment with oral IN resulted in a ~12,000-fold increase in mean RNA expression of CYP1A1, a gene directly regulated by activated AhR, in human colon biopsy samples.

NF-κB Pathway: Indigo Naturalis can regulate intestinal flora, reduce inflammation, repair intestinal mucosa, and improve the physiological status of DSS-induced UC mice; its anti-UC mechanism may be involved in inhibiting TLR4/MyD88/NF-κB signal transduction.

IL-17 and Keratinocyte Proliferation: Indigo naturalis, indirubin, indigo, and tryptanthrin have anti-proliferative, anti-inflammatory, and anti-angiogenic effects via regulating the TAK1, JAK3/STAT3, Wnt/β-catenin, Akt/PKB, FAK, and AP-1/c-Jun pathways. Tryptanthrin possesses moderate anti-IL-17 activity, and this is the first reported association of Indigo Naturalis with anti-IL-17 activity through one of its chemical ingredients.

CDK Inhibition: Indirubin was reported to inhibit cyclin-dependent kinase and signal transducer and activator of transcription-3 (STAT3) activities, and keratinocyte proliferation in vitro.

Antiviral Targets: Tryptanthrin significantly targeted viral enzymes like RNA-dependent RNA polymerase and PLP2 that are involved in the late stages of HCoV-NL63 replication, moderating viral RNA genome synthesis and progeny virus production.

4. Scientific Evidence by Area of Use

4.1 Inflammatory Bowel Disease — Ulcerative Colitis

This is the most studied clinical application of Indigo Naturalis in the modern era, with multiple randomized controlled trials (RCTs) conducted primarily in Japan.

Multicenter Double-Blind RCT (Gastroenterology, 2018): Indigo naturalis (IN) is a traditional Chinese medicine that contains ligands for the aryl hydrocarbon receptor and promotes regeneration of the mucosa by inducing production of interleukin-22. IN might induce mucosal healing in patients with ulcerative colitis (UC), and a randomized controlled trial was performed to investigate the safety and efficacy of IN in patients with UC. In the intent-to-treat analysis, a significant, dose-dependent linear trend in proportions of patients with clinical responses was observed: 13.6% with a clinical response to placebo, 69.6% to 0.5 g IN, 75.0% to 1.0 g IN, and 81.0% to 2.0 g IN (Cochran-Armitage trend test P < .0001 compared with placebo). Proportions of patients in clinical remission at week 8 were significantly higher in the 1.0 g IN group (55.0%, P = .0004) and the 2.0 g IN group (38.1%, P = .0093) than in the placebo group (4.5%). Proportions of patients with mucosal healing were 13.6% in the placebo group, 56.5% in the 0.5 g IN group, 60.0% in the 1.0 g IN group, and 47.6% in the 2.0 g IN group (P = .0278 compared with placebo). Although mild liver dysfunction was observed in 10 patients who received IN, no serious adverse events were observed within the trial period. In a randomized, placebo-controlled trial, 8 weeks of IN (0.5–2.0 g per day) was found to be effective in inducing a clinical response in patients with UC. However, IN should not yet be used because of the potential for adverse effects, including pulmonary arterial hypertension.

Short-Term Double-Blind Multicenter RCT: A multicenter, randomized controlled trial was conducted between December 2015 and October 2018. Forty-six patients with mild to moderate active UC (Lichtiger index: 5–10) were randomly assigned to the IN group or the placebo group and received 5 capsules (500 mg) twice a day for 2 weeks, and efficacy was investigated according to blood tests and the Lichtiger index before and after administration, along with adverse events.

One-Year Prospective Study: Recent studies suggested a favorable effect of IN in inducing remission for refractory UC; however, the maintenance effect remained unknown. A prospective uncontrolled open-label study was conducted, in which patients with moderate to severe active UC (clinical activity index [CAI] ≥ 8) took 2 g/day of IN for 52 weeks.

Open-Label Dose-Escalation Study (Treatment-Refractory UC): This study assessed the safety, efficacy, and colon AhR activity of IN given orally to patients with treatment-refractory UC. The role of AhR in IN benefit was further evaluated with an AhR antagonist in a murine colitis model. The study sequentially treated 11 patients with UC with either IN 500 mg/day or 1.5 g/day for 8 weeks, followed by a 4-week non-treatment period. The primary efficacy endpoint was clinical response at week 8, assessed by total Mayo score.

Evidence Summary — UC: Both preclinical and clinical studies support the efficacy of IN for UC. UC is an intractable inflammatory bowel disease with limited therapeutic strategies, making it important to explore more efficient and safer drugs. IN possesses many pharmacological activities, including anti-inflammatory, antioxidant, and immunomodulatory activities, and the treatment potential of IN for UC has been proven by numerous preclinical and clinical studies in recent years. The overall quality of evidence is moderately strong, anchored by at least one multicenter RCT, though the study sizes remain relatively small and the safety concern of pulmonary arterial hypertension has constrained further large-scale clinical rollout.

4.2 Psoriasis

Topical Clinical Studies: Clinical studies have demonstrated that Indigo naturalis used as topical monotherapy is efficacious in treating patients with mild-to-moderate psoriasis, although the validity of these studies is challenged by intra-patient treatment comparison designs.

Systematic Review and Meta-Analysis: Indigo naturalis is effective against psoriasis. Indigo, indirubin, and tryptanthrin, the main active components of indigo naturalis, have anti-inflammatory properties. The findings demonstrated a higher response rate in the Chinese herbal medicine (CHM) formula groups than in the control group for Psoriasis Area and Severity Index 60 (PASI60) (Rate difference [RD] = 0.22, p < .0001). Among all adverse events, only the incidence of gastrointestinal adverse reactions was higher in the CHM formula group than in the control group (RD = 0.09, p < .0001).

Nanofibrous Patch Trial (2025): A prospective, randomized, semi-compartmental paired, positive drug-controlled trial evaluated an IN nanofibrous patch formulation for chronic plaque psoriasis. The efficacy of the 15% IN-PCL/PEO patch was comparable to that of clobetasol propionate and was more effective than that of the IN ointment. Notably, there was no skin staining or systemic toxicity observed in the groups treated with the IN-PCL/PEO nanofibrous patches, and pathological examinations of the liver, spleen, and kidney indicated good biocompatibility.

Mechanism in Psoriasis: Indirubin inhibits the hyperproliferation and differentiation of keratinocytes and expression of pro-inflammatory mediators; it also suppresses the expression of IL-17 in γδ T cells. Tryptanthrin was reported to inhibit interferon-γ production by lymphocytes from Peyer's Patches, and nitric oxide and prostaglandin E2 synthesis by murine macrophages.

Evidence Summary — Psoriasis: The evidence base for topical IN in mild-to-moderate psoriasis is relatively well-developed and includes several controlled trials and a systematic review. Evidence for oral IN in psoriasis is more limited. The quality of the evidence is moderate; most topical studies are from a small number of investigator groups, and methodological limitations (intra-patient designs) have been noted.

4.3 Leukemia

Indirubin, isolated from Indigo Naturalis, was used as a new agent to treat leukemia in China in the 1970s. Indirubin, one of the key components of medicinal plants including Isatis tinctoria, Polygonum tinctorium, and Strobilanthes cusia, possesses great medicinal efficacy in the treatment of chronic myelocytic leukemia (CML). A number of reports suggested that SCK and its processed medicines could be promising drug candidates for multiple diseases especially promyelocytic leukemia.

Evidence Summary — Leukemia: Clinical use of indirubin for CML in China dates back to the 1970s and provided early signals of efficacy. Modern mechanistic studies have focused on CDK inhibition and STAT3 suppression. However, the large-scale RCT evidence in leukemia is limited, and much of the current research interest has shifted to derivative compounds rather than crude IN.

4.4 Antiviral Activity

Strobilanthes cusia is a Chinese herbal medicine used in the treatment of respiratory virus infections. The methanol extract of S. cusia leaf was studied for anti-HCoV-NL63 activity. The methanol extract of S. cusia leaf effectively inhibited the cytopathic effect (CPE) and virus yield (IC50 = 0.64 μg/mL) in HCoV-NL63-infected cells, and this extract potently inhibited HCoV-NL63 infection in a concentration-dependent manner. These results are limited to in vitro cell culture models; no clinical trials in humans for antiviral indications have been conducted.

4.5 Anti-inflammatory and Antipyretic Activity

In a study evaluating the antinociceptive, anti-inflammatory, and antipyretic effects of methanol extract of Strobilanthes cusia leaf, the results showed that the extract significantly inhibited the writhing responses of mice and decreased the licking time on both the early and late phases of the formalin test in a dose-dependent manner. It also reduced the paw edema induced by carrageenan in rats. This evidence is preclinical (animal models only) and does not yet extend to human clinical trials.

4.6 Antimicrobial Activity

Tryptanthrin exhibits antifungal effects against Microsporum lanosum and Trichophyton tonsurans with a minimal inhibitory concentration of 5 μg/mL. Tryptanthrin has documented pharmacological properties including antifungal activity against dermatophytes and antibacterial activity against Helicobacter pylori. These antimicrobial findings are currently limited to in vitro testing; no clinical trials in humans have been conducted for these indications.

5. Body Systems and Health Areas Associated with Assam Indigo

• Gastrointestinal system: Ulcerative colitis; intestinal mucosal healing; modulation of intestinal microbiota.
• Dermatological system: Psoriasis (topical and potentially oral); inflammatory skin conditions; nail psoriasis.
• Hematological/oncological: Chronic myelocytic leukemia (historical clinical use of indirubin); promyelocytic leukemia (preclinical and early clinical data).
• Immune system: Immunomodulation via AhR, NF-κB, JAK/STAT3, and IL-17 pathways; regulation of Th17 polarization.
• Respiratory system: Traditional use in epidemic respiratory infections; antiviral activity against human coronaviruses in vitro.
• Infectious diseases: Traditional application for influenza, encephalitis B, meningitis, viral pneumonia, and mumps; in vitro antimicrobial data.
• Oral and ENT mucosa: Traditional use for aphthae (mouth ulcers), sore throat, and gingivitis.

6. Dosage Forms and Reported Dosages from Studies

Contents of 2% indigo and 0.13% indirubin are the minimum requirements for the quality control of IN in the Pharmacopeia of the People's Republic of China.

The following dosages have been reported in specific clinical studies:

• Oral IN for UC (multicenter RCT): 0.5 g, 1.0 g, or 2.0 g of IN daily for 8 weeks, compared with placebo.
• Oral IN for mild-to-moderate UC (double-blind RCT): 5 capsules (500 mg) twice a day (1,000 mg twice daily) for 2 weeks.
• Oral IN for moderate-to-severe active UC (prospective study): 2 g/day for 52 weeks.
• Oral IN for refractory UC (open-label dose-escalation): 500 mg/day or 1.5 g/day for 8 weeks, followed by 4 weeks without treatment.
• Qing-dai powder (QDP) for intractable UC (clinical practice): 7.5 g/day (loaded in capsules, orally, twice a day) for 1–2 weeks.

These dosages apply specifically to Indigo Naturalis and are not interchangeable with raw plant material dosing. The clinical studies above were conducted under supervised medical settings and the findings have been reported in peer-reviewed journals.

7. Safety Considerations and Drug Interactions

Pulmonary Arterial Hypertension (PAH)

Although Indigo Naturalis (IN) is effective for patients with active ulcerative colitis (UC), IN was associated with adverse events (AEs), including pulmonary arterial hypertension (PAH). Accumulating evidence shows that IN is effective for the treatment of UC, but it induces some adverse events including PAH, intussusception, and an increase in liver enzyme levels. PAH was reversible in all patients who underwent long-term (>8 weeks) treatment with IN; however, some required treatment. Intussusception occurred within 2 months of IN treatment, and surgery was required in 4 of the 10 cases reported.

This safety signal was significant enough that a major RCT was terminated: the trial was terminated because of a report of pulmonary arterial hypertension in a patient who used self-purchased IN for 6 months.

Hepatotoxicity

The use of Indigo Naturalis in treating inflammatory diseases is clinically restricted by severe adverse events, including pulmonary arterial hypertension and hepatotoxicity. In the multicenter RCT, mild liver dysfunction was observed in 10 patients who received IN.

Nationwide Japanese Survey Data

A nationwide survey, using questionnaires, was conducted by the research group funded by the Ministry of Health, Labour and Welfare of Japan, between June 2017 and September 2018. A first questionnaire determined the occurrence of AEs associated with therapeutic use of IN or herbal medicines containing IN in patients with UC. A second survey identified the clinical characteristics of patients who developed IN-associated critical AEs, namely liver dysfunction, PAH, and intussusception. Across 337 participating institutions, 49,320 patients with UC were identified, with IN used in 877 (1.8%).

Additional Adverse Events

Adverse events reported in small studies and case reports of indigo naturalis use include phlebitis-induced colitis and reversible pulmonary arterial hypertension, as well as mild liver dysfunction, abdominal pain, and headache. A case report describes the development of pancreatitis in an 11-year-old boy with refractory Crohn disease; after 2 doses of indigo naturalis, the patient developed epigastric pain and vomiting along with elevated lipase and amylase levels. Topical indigo naturalis may cause pruritus, rash, erythema, and nasopharyngitis.

Drug Interactions: CYP Enzyme Induction

A metabolite of indirubin was identified as indigo carmine. Indirubin can induce CYP1A1, CYP1A2, or CYP1B1 CYP enzymes and thus accelerate its own metabolism. This induction of cytochrome P450 enzymes represents a potential interaction risk with other drugs metabolized by these enzymes. This is documented in vitro but has not been fully characterized in large human pharmacokinetic studies.

Constituent-Specific Toxicity Profiling

The toxic effects of crude IN are believed to originate from other chemical constituents, such as indigo and indirubin, rather than from tryptanthrin itself. Validating tryptanthrin as a safe, purified alternative is a critical toxicological priority to overcome the clinical limitations of the crude extract.

Regulatory Status

In Japan, Qing-Dai is not currently approved by the Pharmaceuticals and Medical Devices Agency; it is sometimes used by patients at their own discretion for the treatment of ulcerative colitis that has not responded to standard evidence-based therapy. The Chinese Pharmacopoeia includes official quality standards for both Qingdai and Nanbanlangen.

References

• Wikipedia — Strobilanthes cusia
• PubMed — Strobilanthes cusia (Nees) Kuntze, a multifunctional traditional Chinese medicinal plant, and its herbal medicines: A comprehensive review (2020)
• PMC — A Comprehensive Review of the Chemistry, Pharmacokinetics, Pharmacology, Clinical Applications, Adverse Events, and Quality Control of Indigo Naturalis (2021)
• Gastroenterology — Efficacy of Indigo Naturalis in a Multicenter Randomized Controlled Trial of Patients With Ulcerative Colitis (2018)
• PMC — Combination Therapy with Indigo and Indirubin for Ulcerative Colitis via Reinforcing Intestinal Barrier Function (2023)
• PMC — Treatment-refractory ulcerative colitis responsive to indigo naturalis (2022)
• PMC — Efficacy and safety of short-term therapy with indigo naturalis for ulcerative colitis: An investigator-initiated multicenter double-blind clinical trial (2020)
• PMC — One-year clinical efficacy and safety of indigo naturalis for active ulcerative colitis: a real-world prospective study (2022)
• PMC — Indigo naturalis as a potential drug in the treatment of ulcerative colitis: a comprehensive review of current evidence (2024)
• PMC — Evidence and potential mechanism of action of indigo naturalis and its active components in the treatment of psoriasis (2024)
• PMC — Clinical efficacy and IL-17 targeting mechanism of Indigo naturalis as a topical agent in moderate psoriasis (2017)
• Frontiers in Pharmacology — Efficacy of indigo naturalis nanofibrous patches in the treatment of chronic plaque psoriasis: a 4-week prospective, randomized trial (2025)
• Journal of Gastroenterology — Adverse events in patients with ulcerative colitis treated with indigo naturalis: a Japanese nationwide survey (2019)
• Gastroenterology — Pulmonary Arterial Hypertension Associated With the Chinese Herb Indigo Naturalis for Ulcerative Colitis: It May Be Reversible (2018)
• PubMed — Adverse events in patients with ulcerative colitis treated with indigo naturalis: a Japanese nationwide survey (2019)
• PMC — Antiviral Action of Tryptanthrin Isolated from Strobilanthes cusia Leaf against Human Coronavirus NL63 (2020)
• PubMed — Evaluation of antinociceptive, anti-inflammatory and antipyretic effects of Strobilanthes cusia leaf extract in male mice and rats (2003)
• PMC — High-Quality Genome of the Medicinal Plant Strobilanthes cusia Provides Insights Into the Biosynthesis of Indole Alkaloids (2021)
• PMC — Qing-dai powder promotes recovery of colitis by inhibiting inflammatory responses of colonic macrophages in dextran sulfate sodium-treated mice (2015)
• Chinese Medicine / Springer — From natural dye to herbal medicine: a systematic review of chemical constituents, pharmacological effects and clinical applications of indigo naturalis (2020)
• Scientific Reports — Clinical outcomes of patients with remitting ulcerative colitis after discontinuation of indigo naturalis (2024)
• PMC — Advances on Ethnobotanical, Phytochemical, and Preclinical Studies of Strobilanthes crispus and Strobilanthes cusia (Acanthaceae) for Drug Development Purpose (2025)
• PMC — Identification of novel flavin-dependent monooxygenase from Strobilanthes cusia reveals molecular basis of indoles' biosynthetic logic (2023)
• PMC — Rapid Identification and Verification of Indirubin-Containing Medicinal Plants (2015)
• Journal of Applied Toxicology — Pharmacokinetics and Acute Safety Evaluation of Tryptanthrin, A Bioactive Constituent of Indigo naturalis (2026)