ISATIS ROOT & LEAF (Isatis tinctoria)

Latin: Isatis tinctoria, Isatis  indigotica
Chinese: Ban lan gen (root)  Da qing ye (leaves)

WHAT IT DOES: Isatis root and leaf are bitter in taste and cold in action.  They reduce fever and heat, cool the blood and throat, and reduce activity of virulent virus’ and microbes.  

RATING: red, due to safety issues.

SAFETY ISSUES: This herb is very strong, and should not be used for extended periods of time, or in patients with severe weakness.  Long-term use of pure Isatis can reduce beneficial intestinal bacteria.  Use only under the guidance of a trained professional.  However, adverse reactions are much less if given with other herbs in a combination herbal formula.
Note: In 1990, there were 38 reports in China and 16 in Taiwan of adverse reactions to isatis (Ko, 1999).

• Dried powder: two to three grams per day
• Concentrated dried decoction extract: one to four grams per day.

Isatis is one of the most effective TCM herbs used as an herbal antibiotic, antiseptic and anti-viral.  TCM doctors use it whenever there are signs of fever or toxic heat from viral illness, blood poisoning, leukemia, hepatitis, meningitis, scarlet fever, sinus infections, laryngitis, tonsillitis, mumps, and other similar ailments.  It is an effective alternative to Western prescription antibiotics in some cases.  Although the root is used most commonly, the leaves are useful as well.  TCM doctors say isatis leaves “go to the upper part of the body” more than the root, so leaves are used for upper respiratory infections along with the root.
I find it very safe for short-term use, less than three weeks.  Long-term use can weaken digestion, and sometimes can induce a very interesting but reversible feeling of internal coldness, to the point of shivering.  I have experienced this phenomenon, and it was a truly enlightening sensory introduction to the concept of “coldness.” I always use this herb with caution, as it can induce nausea in sensitive individuals and weaken digestion over time.  Isatis contains several potent dark pigments, including blue indigo and red-colored indirubin.

Research Highlights

• Indirubin (found in Isatis) binds to and blocks enzymes that govern cell division, thus stopping the proliferation of blood cancer cells.  An article in Nature Cell Biology reported the results of a study examining the effects of indirubin extract on chronic myelocytic and chronic granulocytic leukemia.  According to the report, 26 percent of the chronic myelocytic leukemia patients showed complete remission and 33 percent showed partial remission.  Remissions lasted up to several years.  The toxicity of the extract was relatively mild (Hoessel et al., 1999).

• The Experimental Pharmaceutical Factory at the Beijing College of TCM found alcohol to be superior to water for extracting indigotin and indirubin (Zhang et al., 1990).  Additionally, meisoindigo, an indirubin derivative, seems to inhibit cancer cell replication more effectively due to its superior absorption (Ji et al., 1991).  From an herbalist’s point of view, these two studies might argue for the treatment of leukemia with alcohol extracts of herbs containing indigo and indirubin, such as isatis, combined with digestion improving herbs such as black pepper or long pepper.  Other herbs which have shown anti-leukemic action in the laboratory include boswellia gum and turmeric root.

• In a controlled rat model of chronic Pseudomonas aeruginosa lung infection mimicking cystic fibrosis, isatis and genkwa flower (Daphne giraldii / yuan hua) were each able to reduce the incidence of lung abscess and to decrease the severity of lung pathology (Song et al., 1996).  We now know that alterations in fatty acid metabolism are responsible for many of the symptoms of cystic fibrosis symptoms, and that DHA (docosahexaenoic acid) derived from marine algae or fish is effective therapy for reversing these symptoms (Freedman et al., 1999).  Consequently, I wonder if the combination of these TCM herbs and DHA would provide even greater benefit for this disease.

• In laboratory studies of mice, isatis root polysaccharides increased the weight of the spleen and number of white blood cells and lymphocytes significantly, as well as neutralizing some of the immune suppression caused by hydrocortisone (Xu and Lu, 1991).

• A number of studies of acute viral respiratory tract infections and infections normally requiring antibiotic therapy have demonstrated the efficacy of a combination of echinacea root, white cedar leaf tips and wild indigo root, which contains similar compounds to isatis (Wustenberg et al., 1999).