- Ban Lan Gen
- indigo wood
- Chinese indigo
- woad root
For Patients & Caregivers
Bottom Line: 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. However, this botanical has not yet been evaluated in clinical trials and therefore it remains uncertain whether these effects occur in the human body.
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 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.
A total of 20 patients receiving radiation therapy for head and neck cancer were randomly divided into control or treatment groups. The treatment group gargled with an indigowood root powder solution dissolved in double-distilled water for 3 minutes, and then swallowed it, before meals daily for 7 weeks. Researchers found this treatment significantly reduced the severity of radiation mucositis, anorexia, and difficulty in swallowing in treated patients compared with the control group.
Acute bacterial conjunctivitis
A study was conducted in 200 patients with acute bacterial conjunctivitis. Participants were randomly divided into either of two treatment groups: isatis root or levofloxacin eyedrops, 6 times daily for 7 days. Both researchers and patients did not know which eyedrops they received. Isatis root was found to be comparably effective to levofloxacin treatment. Two patients experienced minor effects: one reported the feeling of a foreign substance, while another experienced irritating pain in the eyes. Symptoms resolved after both patients closed their eyes and rested for 3 minutes. Investigators concluded that isatis root eyedrops may be useful to treat acute bacterial conjunctivitis.
- 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.
For Healthcare Professionals
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 clinical study demonstrated its utility for reducing the severity of radiation mucositis (15).
Isatis leaf has both overlapping and different properties from isatis root.
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).
You WC, et al. Effect of extracts from indigowood root (Isatis indigotica Fort.) on immune responses in radiation-induced mucositis. J Altern Complement Med. 2009;15:771-778.
This study investigated the effect of indirubin taken as isatis root powder on acute radiation-induced mucositis. A total of 20 patients who received radiation therapy for head and neck cancer were enrolled and randomized into a control or treatment group. The treatment group gargled with a solution made from indigowood root powder dissolved in double-distilled water for 3 minutes, and then swallowed it, before meals daily for 7 weeks. Results suggested that indigowood root significantly reduced severity of radiation mucositis (P=0.01), anorexia (P=0.002), and swallowing difficulty (P=0.002) in treated patients compared with the control group. The authors concluded that indirubin may play a therapeutic role to improve radiation-induced mucositis, anorexia, and difficulty swallowing, but that exact mechanisms and pathways should be further studied.
Qi CX , et al. [Clinical research of isatis root eyedrops on the acute bacterial conjunctivitis]. Zhong Yao Cai. 2007;30:120-122.
This randomized, double-blind parallel study evaluated the efficacy and safety of isatis root eyedrops on 200 cases of acute bacterial conjunctivitis. Patients received either isatis root or levofloxacin eyedrops (test and control agent, respectively), 6 times daily for 7 days. Efficacy rates in the isatis root vs levofloxacin groups were 90% and 93%, respectively, a difference that was not statistically significant. Two patients experienced side effects: one reported the feeling of a foreign substance, while another experienced irritating pain in the eyes. Symptoms resolved after both patients closed their eyes and rested for 3 minutes. The investigators concluded that isatis root eyedrops exhibited an excellent efficacy and safety profile in the treatment of acute bacterial conjunctivitis.