- Dyer’s woad leaf
- Da Qing Ye
- Qing Dai
For Patients & Caregivers
How It Works
Isatis leaf has not been shown to treat or prevent cancer.
Isatis leaf extract is derived from the same plant from which indigo dye is made. It is used in combination with isatis root and other herbs both in Traditional Chinese Medicine and in Ayurveda to treat the common cold, sore throat, mumps, respiratory ailments, other febrile diseases, hepatitis, and malignant tumors. Isatis root has both similar and different properties from isatis leaf.
Isatis leaf has anti-inflammatory properties. 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. Qing Dai, the pulverised form of isatis leaf, has been shown useful for the treatment of psoriasis. It was also found effective against ulcerative colitis, but its use has been associated with pulmonary arterial hypertension. However, the symptoms resolved after discontinuing Qing Dai.
- 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 treat diarrhea or gastrointestinal disorders Isatis extracts have anti-inflammatory activity in the laboratory setting. A pulverized version of the extract is used in China to treat ulcerative colitis.
- To treat hepatitis Isatis extracts have anti-inflammatory effects.
- To treat HIV and AIDS There is no scientific evidence to support this claim.
- To treat respiratory infections Although isatis has antiviral activity, there is no evidence from clinical trials that it can effectively treat infections.
- Pulmonary arterial hypertension has been associated with use of Qing Dai in patients with ulcerative colitis. Symptoms improved after discontinuing use.
- Colitis involving wall thickening and edema that affected the large bowel, abdominal pain and bloody diarrhea were associated with use of Qing Dai in patients with ulcerative colitis. Symptoms improved after stopping use.
For Healthcare Professionals
Isatis leaf 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 root and other herbs to treat the common cold, sore throat, mumps, respiratory ailments, other febrile diseases, hepatitis, and malignant tumors (1) (2). Isatis root has both overlapping and different properties from isatis leaf.
Isatis leaf is one of the ingredients used in PC-SPES, an herbal formula used to treat prostate cancer. It is also used in Danggui Longhui Wan, a formula used to treat chronic myelocytic leukemia (CML) in China (4). In vitro and in vivo studies indicate that isatis has antimicrobial, antiendotoxic (5), antiviral (6) (7) (8), immunostimulatory (9), anti-inflammatory (10) (11), and chemotherapeutic (12) properties. In several instances, the pharmacologic effects of isatis leaves were found to be greater than that of the roots (5) (8). A preliminary study in healthy volunteers reported anti-inflammatory (13) effects with use of topical isatis leaf.
The pulverized form of isatis leaf, known as Qing Dai, has been used in small studies for the treatment of ulcerative colitis that showed benefit (3) (20). A randomized controlled trial also reported effectiveness (21); however, the study was terminated following a report of pulmonary arterial hypertension (PAH) in a patient (not a study participant) who self-medicated with Qing Dai. Additional cases of Qing Dai-associated PAH have been reported in patients with ulcerative colitis, but symptoms improved after discontinuing use (22) (23).
In other studies, topical use of Qing Dai was found useful for the treatment of psoriasis (24) (25) (26).
Mechanism of Action
Isatis leaf inhibits cyclooxygenase-2 (COX-2) with preferential effects on COX-2–catalysed prostaglandin synthesis, in vitro (10). The alkaloid tryptanthrin has been identified as the inhibitor of COX-2 (10) and 5-lipoxygenase (5-LOX) (13) (18). Indirubin, another active component, inhibits cyclin-dependent kinases (CDKs) and prevents proliferation by arresting cells in the G2/M phase (4). Other alkaloids isolated from isatis inhibit leukocyte function and attenuate the production of mediators related to inflammatory responses (11). A compound derived from isatisine A showed moderate anti-HIV-1 activity (7). But better virucidal activity has been reported with leaf, not root extracts using a swine pseudorabies model (8).
Animal models suggest that isatis leaf can reduce allergic airway inflammation and hyper-responsiveness by inhibiting production of Th2 cytokines IL-4 and IL-5, and RANTES (9). And when used as postexposure prophylaxis, isatis leaf attenuated lung tissue damage and reduce lung virus titers (6). Findings also showed induction of hepatocellular cancer cell death by isatis via a caspase-independent apoptotic pathway (12).
In other mechanistic studies, Qing Dai was shown to prevent bisphosphonate-induced gastrointestinal injury by suppressing mitochondrial ROS production, the main cause of cellular lipid peroxidation (27). Its anti-psoriatic effects are believed to be mediated by modulating the proliferation and differentiation of keratinocytes (28), and by down regulating the IL-17 pathway (29).
- Pulmonary arterial hypertension has been associated with use of Qing Dai in patients with ulcerative colitis (22) (23). Symptoms improved after discontinuing use.
- Colitis involving wall thickening and edema that affected the large bowel, abdominal pain and bloody diarrhea were associated with use of Qing Dai in patients with ulcerative colitis. Cessation of use resulted in symptom resolution (30).