What is bupleurum?
Also known as radix bupleuri, it refers to the dried root of Bupleurum chinense DC. or Bupleurum scorzonerifolium Willd., which are perennial umbelliferous plants. Else, it is also being called thorowax root. They are usually collected in spring and winter for medicinal purpose, stems, leaves, and dirt removed, and then dried in the sun.
Modern pharmacological actions
Bupleurum contains A, B, C, D types of saikosapoins, sterol, essential oils like bupleurumol and eugenol, fatty acids like oleic acid, linoleic acid, palmitic acid, and stearic acid, and polysaccharide, etc. And it has the typical actions as follows:
1. Aritipyretic effect. Early studies found that large dose of bupleurum decoction, 5 grams/kg, could bring down a fever on rabbits that were induced fever artificially;
2. Sedation and analgesia. Taking saikosaponins orally could calm down mice and prolong the sleep induced by benzodiazepines. In addition, sailkosaponins could ease pain while relieving a cough;
3. Anti-inflammation. Saikosaponin at the dose of 600mg/kg could dramatically lower paw swelling induced by dextran and serotonin (5-HT) in rats;
4. Antiviral effect. Reportedly Injection Bupleuri could inhibit influenza virus effectively;
5. Effects on the liver. Fed on bupleurum, the rats, with acute liver dysfunction induced by moldy rice, have a much lower level of ALT and AST.
Related Chinese herbal formulas
This herb is considered bitter, acrid, and slightly cold in nature and covers meridians of liver and gallbladder.
Main functions are to resolve superficies for clearing heat, disperse entangled liver qi for relieving qi stagnation, and promote spleen yang. Main benefits and indications are fever due to cold or influenza, malaria, alternating chills and fever, fullness and pain in chest and rib cage, irregular menstruation, and prolapses of rectum and uterus.
Usual dosage is 3 to 10 grams in decoction.
Potential side effects and contraindications
Bupleurum is considered nontoxic in TCM wise if only taken properly. However, beware of the dried root of bupleurum longibrachiatum Turcz., which can’t be used for medicinal purpose due to its poisonousness.
Else, it should be avoided by those suffering from hyperaction of liver Yang, liver wind agitation, fire excess from Yin deficiency, and reversed flow of qi, etc.