Isatis Root

Isatis Root

Common Names

  • Ban Lan Gen
  • Indigo wood
  • Chinese indigo
  • Woad root

For Patients & Caregivers

Isatis root has not been extensively studied in clinical trials, so it is not known if it works in humans.

Isatis root extract is derived from the same plant from which indigo dye is made. It has been used in combination with other botanicals in traditional Chinese medicine and Ayurveda for thousands of years.

In animal tests, it reduced inflammation, fever, and pain perception. Isatis also stimulated immune cells in tissues that destroy foreign particles as they pass in the bloodstream. Laboratory studies suggest that indirubin, an active compound in isatis, stops cell duplication and therefore may be useful in cancer treatment. Other lab experiments show that isatis extract can kill certain viruses and counteract some symptoms and tissue damage from bacterial infections, but it remains uncertain whether these same effects occur in the human body.

A small study indicates that an isatis root extract solution may be helpful in reducing radiation-induced mucositis in head and neck cancer patients.

Isatis leaf has both similar and different properties from isatis root.

  • To treat bronchitis and relieve chest congestion
    Laboratory research suggests that isatis root has anti-inflammatory and immune-stimulating activity, but there is no proof from clinical trials that it can relieve bronchitis and chest congestion.
  • To treat the common cold
    Although antiviral and immune-stimulating activity has been shown in lab studies, there is no proof from clinical trials that isatis root can effectively treat the common cold.
  • To prevent and treat cancer
    Lab studies show that an active compound in isatis stops cell duplication, but there is no evidence from clinical trials that it can prevent or treat cancer. In China, isatis is used in combination with other botanicals to treat chronic myelogenous leukemia.
  • To reduce severity of radiation-induced mucositis
    A small study in head and neck cancer patients suggested that a specific isatis root extract solution could reduce severity of mucositis, anorexia, and difficulty swallowing in treated patients compared with a control group.
  • To reduce fever
    Animal studies show that isatis root can reduce fever, but no clinical trials have been performed to test this use in humans.
  • To fight viral infections
    Although isatis root has antiviral activity, there is no evidence from clinical trials that it can effectively treat infections.
  • To treat bacterial conjunctivitis
    One clinical study suggests that isatis root eyedrops may be effective to treat bacterial conjunctivitis. However, further study is needed to confirm this effect.
  • To prevent and treat severe acute respiratory syndrome (SARS)
    Although isatis root has antiviral activity, we do not know whether this effect occurs in the human body. No human studies have been performed to verify anecdotal reports that isatis may help to ward off SARS.
  • Some compounds in isatis root could have activity against SARS, but these are only lab experiments. These compounds would need to be further developed and tested because many compounds in isatis root have been found to occur at low levels. Relying solely on herbal supplements to prevent or treat SARS may induce a false sense of security from this deadly disease. Patients with suspected SARS should limit interactions outside the home. The Centers for Disease Control (CDC) recommends proper hygiene such as frequent hand washing and wearing a surgical mask to help prevent the spread of SARS.

Oral: None reported.

Eyedrops:  Feeling a foreign substance or irritation in the eyes (one report each). Symptoms resolved after the patients closed their eyes and rested for 3 minutes.

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For Healthcare Professionals

Ban Lan Gen Chong Ji
Radix isatidis baphicacanthi, Isatis tinctoria, Isatis indigotica

Isatis root is derived from the isatis plant and is a source of indigo dye. In both traditional Chinese medicine (TCM) and Ayurveda, it is used in combination with isatis leaf and other herbs to treat the common cold, sore throat, mumps, respiratory ailments, other febrile diseases, hepatitis, and malignant tumors (1) (2). One such formula, Danggui Longhui Wan, is used in China to treat chronic myelocytic leukemia (CML) (3). Isatis root has also been promoted to ward off severe acute respiratory syndrome (SARS).

In vitro assays have identified specific compounds in isatis root with potential anti-SARS (4) and anti-influenza activity (5), as well as cytotoxic activity against human liver cancer and leukemia cell lines (6). Several in vitro and animal studies also demonstrate antimicrobial (7), antiviral (8) (9), anti-endotoxic (10), immunostimulatory (3) (11), chemotherapeutic (12), and radioprotective effects (13). Animal models indicate anti-inflammatory, antipyretic, and antinociceptive effects (13) (14).

In one clinical trial, isatis root eyedrops were an effective treatment for bacterial conjunctivitis (7). A small randomized study demonstrated the utility of an isatis root extract solution for significantly reducing severity of radiation mucositis, anorexia, and swallowing difficulty in head and neck cancer patients  (15).

Isatis leaf has both overlapping and different properties from isatis root.

  • Bronchitis
  • Cancer treatment
  • Chest congestion
  • Common cold
  • Fever
  • Infections
  • Radiation-induced mucositis
  • Severe acute respiratory syndrome (SARS)

Isatis root exerts immunostimulatory effects by enhancing reticuloendothelial system function (11). Sinigrin and indigo have been identified as the compounds responsible for potential SARS inhibition (4). Clemastanin B, a major lignan compound in isatis, targets viral endocytosis, uncoating, and nuclear export of viral ribonucleoproteins (5). A crude extract of isatis root prevented influenza virus attachment to cells and therefore viral replication, but was inactive against respiratory syncytial virus, adenovirus, parainfluenza virus and enterovirus (19). Another component of isatis root demonstrates dose-dependent anti-endotoxic effects on lipopolysaccharide-induced expression of membrane-organizing extension spike protein, a main endotoxin receptor (10). Alkaloids isolated from isatis can inhibit leukocyte function and reduce inflammatory response (20). One animal study found that indigo root extract reduced tissue injury, enhanced hematopoietic system recovery, modulated serum inflammatory cytokines, and improved severe enteropathy in whole body irradiated mice (13).

An in vitro study also found that an ethanol extract of isatis root had a dose-dependent cytotoxic effect against human leukemia HL-60 cells (9). Indirubin, an active component of isatis, inhibits cyclin-dependent kinases (CDKs) and prevents proliferation by arresting cells in the G2/M phase (3).

Although some compounds have been identified as exhibiting potential for SARS inhibition, they would need to be developed and tested for efficacy. Many compounds in isatis root occur at low levels (16). In addition, as SARS is a deadly disease, reliance on herbal supplements as prevention or treatment may induce a false sense of security. Patients with suspected SARS should limit interactions outside the home. The Centers for Disease Control (CDC) recommends proper hygiene such as frequent hand washing and wearing a surgical mask to help prevent the spread of SARS (21).

Oral: None reported.

Eyedrops: One report each of feeling a foreign substance and another of irritating pain in the eyes. Symptoms resolved after the patients closed their eyes and rested for 3 minutes (7).

  1. Bensky D, Gamble A. Chinese Herbal Medicine: Materia Medica Revised ed. Seattle, WA: Eastland Press; 1993.

  2. Hoessel R, Leclerc S, Endicott JA, et al. Indirubin, the active constituent of a Chinese antileukaemia medicine, inhibits cyclin-dependent kinases. Nat Cell Biol. May 1999;1(1):60-67.

  3. Wu Y, Zhang ZX, Hu H, et al. Novel indole C-glycosides from Isatis indigotica and their potential cytotoxic activity. Fitoterapia. Mar 2011;82(2):288-292.

  4. Qi CX, Wu XM, Wang XL. [Clinical research of isatis root eyedrops on the acute bacterial conjunctivitis]. Zhong Yao Cai. Jan 2007;30(1):120-122.

  5. Wang Y, Qiao CZ, Liu S, et al. [Evaluation on antiendotoxic action and antiviral action in vitro of tetraploid Isatis indigotica]. Zhongguo Zhong Yao Za Zhi. Jun 2000;25(6):327-329.

  6. Hsuan SL, Chang SC, Wang SY, et al. The cytotoxicity to leukemia cells and antiviral effects of Isatis indigotica extracts on pseudorabies virus. J Ethnopharmacol. May 4 2009;123(1):61-67.

  7. Li J, Liu Y, Fang J, et al. Effect of Radix Isatidis on the expression of moesin mRNA induced by LPS in the tissues of mice. J Huazhong Univ Sci Technolog Med Sci. Apr 2007;27(2):135-137.

  8. Xu YM, Lu PC. [Experimental studies on immunostimulatory effects of the Isatis indigotica polysaccharide]. Zhong Xi Yi Jie He Za Zhi. Jun 1991;11(6):357-359, 325-356.

  9. You WC, Hsieh CC, Huang JT. Effect of extracts from indigowood root (Isatis indigotica Fort.) on immune responses in radiation-induced mucositis. J Altern Complement Med. Jul 2009;15(7):771-778.

  10. Molina P, Tarraga A, Gonzalez-Tejero A, et al. Inhibition of leukocyte functions by the alkaloid isaindigotone from Isatis indigotica and some new synthetic derivatives. J Nat Prod. Oct 2001;64(10):1297-1300.

  11. Centers for Disease Control and Prevention. Public Health Guidance for Community-Level Preparedness and Response to Severe Acute Respiratory Syndrome (SARS) Version 2/3. 2014; Accessed March 11, 2014.

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