Ban Lan Gen
StarIsatis indigotica Fort. (syn. Isatis tinctoria L.)
Traditionally used for
- Nose & throat
- Colds & fever
☯ TCM Properties
Clears Heat and Resolves Toxicity; Cools the Blood; Benefits the Throat
Traditional Chinese Uses
Ban Lan Gen (isatis root) is a cold, bitter herb considered one of the most important herbs in Chinese medicine for clearing Heat toxin and dispersing swellings. It is widely used for acute infectious and inflammatory conditions — including sore throat, swollen lymph nodes, tonsillitis, influenza, and febrile illness — where Heat toxin is the primary pathogen. Its antiviral and anti-inflammatory properties are well-recognized in modern Chinese herbal medicine, and it is one of the most popular herbs for cold and flu prevention in China.
Western Herbalism Properties
Pharmacological Effects
- Antiviral: 50% injection inhibited influenza strains PR8 and JK68-1 in vitro and in chicken embryos; decoction delayed cytopathic changes from influenza virus and adenovirus-7 in human embryonic kidney cells.
- Antibacterial: Decoction or aqueous extract inhibited S. aureus, pneumococcus, alpha streptococcus, H. influenzae, E. coli, S. typhi and Shigella dysenteriae.
- Anti-endotoxic: Several isolated acids and a quinazolinone were antiendotoxic in the limulus amebocyte lysate test.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 185.
Relationships
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Botanical Description
Isatis tinctoria L. and the closely related Isatis indigotica Fortune ex Lindl. (Brassicaceae) are biennial or short-lived perennial herbs growing 50-130 cm tall from a stout taproot. In the first year they form a basal rosette of bluish-green, oblong-lanceolate leaves; in the second year an erect, branched flowering stem bears clasping, arrow-shaped stem leaves and broad terminal panicles of small, four-petaled yellow flowers. These mature into pendent, flattened, single-seeded silicles that turn dark purple-brown. Native to the steppes of Central Asia, woad was introduced to Europe and East Asia for its leaves' indigo dye and is now cultivated medicinally. The root (Ban Lan Gen) and leaf (Da Qing Ye) are used in TCM and historically in Western herbalism to clear heat and toxins.
Active Constituents
(R,S)-Goitrin (epigoitrin)
Oxazolidine-2-thione, a glucosinolate (progoitrin) breakdown productConcentration: Chinese Pharmacopoeia (2020) marker for Isatidis Radix: not less than 0.020% of the dried root by HPLC
The official assay marker that defines Ban Lan Gen as a drug, and the constituent that most clearly separates the root from the leaf. In restraint-stressed mice it lowered susceptibility to H1N1 influenza and reduced pro-inflammatory cytokine output.
Clemastanin B
Lignan diglycoside (lariciresinol-4,4'-bis-O-beta-D-glucopyranoside)Concentration: one of the major lignans of the root; no official assay limit
Inhibited human and avian influenza A and B viruses in MDCK cells with IC50 values of 0.087 to 0.72 mg/mL, acting after viral entry by blocking uncoating or nuclear export of the viral ribonucleoprotein. Activity is in vitro only.
Indirubin
Bis-indole (indigoid) alkaloidConcentration: present in the root, but the leaf (Da Qing Ye) and the leaf-derived extract (Qing Dai) contain substantially more; the leaf, not the root, is assayed for indigoid content
A cyclin-dependent kinase inhibitor with anti-leukaemic activity in vitro, and the constituent responsible for most of the drug-metabolism signal attributed to Ban Lan Gen: it activates the human pregnane X receptor and induces CYP3A4 transcription, and is a potent aryl hydrocarbon receptor ligand. Any dosing inference from indirubin research should be read as applying mainly to the leaf and to Qing Dai.
Indigotin (indigo)
Bis-indole (indigoid) pigmentConcentration: reported highest in the leaves, then the stems, and lowest in the roots; the Chinese Pharmacopoeia sets indigo not less than 0.020% for the leaf drug Da Qing Ye, not for the root
The blue pigment of the indigo-yielding Isatis plants and an aryl hydrocarbon receptor ligand. Its use as a quality marker belongs to Da Qing Ye and Qing Dai; a root sample assayed on indigo content is being judged by the wrong specification.
Tryptanthrin
Indoloquinazoline alkaloidA minor indole alkaloid isolated from both root and leaf, reported to have antimicrobial and anti-inflammatory activity in vitro.
Isatis root polysaccharide
PolysaccharideThe water-extractable polysaccharide fraction is credited with the immunomodulatory and antiviral activity of aqueous root preparations, including inhibition of hepatitis B virus antigen and DNA output in HepG2.2.15 cells.
Nucleosides and nucleobases (uridine, adenosine, guanine, hypoxanthine, uracil)
Nucleosides and purine/pyrimidine basesAbundant water-soluble constituents of the root that are routinely used together with epigoitrin in chromatographic fingerprinting to authenticate Isatidis Radix.
Indole glucosinolates (glucobrassicin, neoglucobrassicin, 1-sulpho-3-indolylmethyl glucosinolate)
GlucosinolatesCharacteristic Brassicaceae sulfur compounds that are hydrolysed by endogenous myrosinase on maceration to give the isothiocyanates and oxazolidinethiones, epigoitrin among them, that carry much of the root's antiviral and antibacterial activity.
Syringin
Phenylpropanoid glucosideOne of several phenylpropanoid and lignan glucosides of the root; reported as a secondary chromatographic marker rather than a demonstrated active principle.
⚠ Drug Interactions
CYP3A4 substrates (e.g. midazolam, ciclosporin, tacrolimus, many statins)
Indirubin, explicitly identified in the source paper as a component of Ban Lan Gen, activates the human pregnane X receptor and drives CYP3A4 gene transcription (Kumagai et al., Drug Metab Pharmacokinet 2016). The work is cell-based reporter and hepatocyte data; no human pharmacokinetic study of Ban Lan Gen with a CYP3A4 probe has been published. Indirubin content is much higher in the leaf (Da Qing Ye) and in Qing Dai than in the root, so the size of any real-world effect from the root drug is unknown and probably smaller.
Clinical note: Do not treat this as established, but avoid open-ended self-medication with Ban Lan Gen granules in transplant recipients and others on narrow-therapeutic-index CYP3A4 substrates, and monitor levels if it is used.
CYP1A2 substrates (e.g. theophylline, clozapine, tizanidine, olanzapine)
Indirubin and indigo are potent aryl hydrocarbon receptor ligands and induce hepatic CYP1A1/1A2 protein and mRNA in mice, an effect abolished in AhR knockout animals (Sugihara et al., Biochem Biophys Res Commun 2004). Indirubin was the more potent of the two. The indigoid content of the root is low relative to the leaf and to Qing Dai, and no human data exist, so this is extrapolation from the isolated pigments rather than an observed herb-drug interaction.
Clinical note: Relevant mainly as a reason to watch CYP1A2 substrates in patients using indigo-rich Isatis products (Da Qing Ye, Qing Dai) rather than the root; no action needed for ordinary short-course oral Ban Lan Gen.
Intravenous Isatidis Radix-containing injections (Qing Kai Ling injection, Ban Lan Gen injection)
Fractionation of Qing Kai Ling injection showed that only the Isatidis Radix fraction produced vascular leakage after a first intraplantar injection in mice, and that both the whole injection and that fraction directly activated complement C3 in a concentration-dependent way (EC50 218.6 micrograms/mL for the Isatidis Radix fraction); C3a receptor antagonism blocked the reaction (Gao et al., Front Pharmacol 2020). This is complement activation-related pseudoallergy, not IgE-mediated allergy, so a prior sensitising exposure is not required and skin testing does not predict it. Reports of urticaria, erythema multiforme, granuloma and anaphylactic shock come from the injectable products, not from decoctions.
Clinical note: The hazard belongs to the injectable formulations used in China, not to oral decoction or granules. Practitioners outside China should know that a patient who reacted badly to a Qing Kai Ling or Ban Lan Gen injection may have reacted to the Isatis component, and that a negative allergy history does not exclude a repeat reaction.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 9–15 g | Daily | — | — | 中国药典 2020 【用法与用量】9～15g。 【性味与归经】苦，寒。归心、胃经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
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
1
1 verified · 0 unverified
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Antiviral activity of Isatis indigotica root-derived clemastanin B against human and avian influenza A and B viruses in vitro
- Qing-Kai-Ling Injection Induces Immediate Hypersensitivity Reaction via the Activation of Anaphylatoxin C3
- Indirubin, a component of Ban-Lan-Gen, activates CYP3A4 gene transcription through the human pregnane X receptor
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
Antiviral activity of Isatis indigotica root-derived clemastanin B against human and avian influenza A and B viruses in vitro
Clemastanin B, a major lignan of the root (not the leaf), inhibited human H1N1 including the 2009 swine-origin strain, H3N2, influenza B and avian H6N2, H7N3 and H9N2 in MDCK cells, with IC50 values of 0.087 to 0.72 mg/mL. Virus titre fell most when the compound was added early after infection, and viral ribonucleoprotein was retained in the nucleus, pointing to a post-entry step (uncoating or nuclear export) rather than to direct virucidal action. Cell-culture concentrations are high in absolute terms and no plasma concentrations of clemastanin B in humans are known.
Efficacy and safety of Ban-Lan-Gen granules in the treatment of seasonal influenza: study protocol for a randomized controlled trial
This is the published protocol, not the results, of a randomised, double-blind, oseltamivir- and placebo-controlled three-arm trial of Ban-Lan-Gen granules in 177 adults aged 18 to 65 with seasonal influenza (ClinicalTrials.gov NCT02232945), with 5 days of treatment and follow-up to day 21. It is cited here because it is the best-designed clinical evaluation of the drug on record and because it documents how thin the prior clinical evidence base was: the authors state that few evidence-based clinical studies had assessed Ban-Lan-Gen against influenza. No efficacy conclusion can be drawn from a protocol.
Qing-Kai-Ling Injection Induces Immediate Hypersensitivity Reaction via the Activation of Anaphylatoxin C3
Of seven fractions of Qing Kai Ling injection tested in mice, only the Isatidis Radix fraction caused Evans Blue extravasation after a single first injection. Both the whole injection and that fraction activated complement C3 directly and concentration-dependently (half-effective concentrations 0.69% and 218.6 micrograms/mL), and a C3a receptor antagonist abolished the response. The reaction is therefore complement activation-related pseudoallergy rather than IgE-mediated allergy, which explains first-dose reactions to Isatis-containing injections.
Indirubin, a component of Ban-Lan-Gen, activates CYP3A4 gene transcription through the human pregnane X receptor
Indirubin from Ban Lan Gen was shown to activate the human pregnane X receptor and to induce transcription from the CYP3A4 promoter in reporter and hepatocyte systems. This is the primary source behind the CYP3A4 caution carried by clinical herb references for Isatis root; it is cell-based, and its clinical relevance in patients taking the root drug has not been tested.
⚠ Safety & Contraindications
Contraindications
Its use is prohibited in weak patients without excess fire and heat toxin, and cautious in patients with deficiency-cold of the spleen and stomach.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 53–72.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyBen Cao Gang Mu
Ming dynastyReferences
- Jiao Chen, Zongping Zhu, Tianhui Gao, Yi Chen, Qingsong Yang, Chaomei Fu, Yaning Zhu, Fang Wang, Wan Liao. Isatidis Radix and Isatidis Folium: A systematic review on ethnopharmacology, phytochemistry and pharmacology . Journal of Ethnopharmacology (2022) [DOI]
- Qiong Chen, Hai-Yue Lan, Wei Peng, Khalid Rahman, Qing-Chun Liu, Xin Luan, Hong Zhang. Isatis indigotica: a review of phytochemistry, pharmacological activities and clinical applications . Journal of Pharmacy and Pharmacology (2021) [DOI]
- Kazumi Sugihara, Shigeyuki Kitamura, Tsuyoshi Yamada, Takashige Okayama, Shigeru Ohta, Keisuke Yamashita, Mineo Yasuda, Yoshiaki Fujii-Kuriyama, Ken'ichi Saeki, Saburo Matsui, Tomonari Matsuda. Aryl hydrocarbon receptor-mediated induction of microsomal drug-metabolizing enzyme activity by indirubin and indigo . Biochemical and Biophysical Research Communications (2004) [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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