Chai Hu: Bupleurum Root

One of the more peculiar herbs found in Chinese Medicine is the seemingly contradictory herb, Bupleurum. It fits multiple categories, treats alternating symptoms, appears to work best in conjunction with other herbs but has been used in studies on its own with great results. The curious actions and benefits of Bupleurum may be difficult to grasp at first, but once understood can be used to alleviate a wide range of complex symptoms.

Having over 2,000 years of traceable usage, Bupleurum has an extensive medicinal history in Asian cultures. It is first mentioned in the original Chinese materia medica, the Shen Nong Ben Cao Jing. Bupleurum Root is known as “Chai Hu” in Chinese medicine, which translates to “Kindling of the Barbarians” (Chen, 2004). Little is known about the actual origin and meaning behind this name. The Latin name for Bupleurum is Bupleurum radix or Bupleurum falcatum, originating from the Latin word boupleuron: bous meaning ox and pleuron meaning ribs, comparing the shape of the root to ox ribs (Ashour & Wink, 2011). It is also known as Thorowax root, Asian Buplever root, and Hare’s Ear Root (Tierra, 1988). This herb is a part of the Umbelliferae family and has an estimated 190 species within its genus, mostly found in subtropical regions of the Northern hemisphere. It resembles other herbs in the Umbelliferae family such as fennel, anise, and caraway, growing tall shoots up to three feet tall with clusters of yellow flowers (Ashour & Wink, 2011). Although there are over 37 species of Bupleurum, it is mainly the Chinese Bupleurum that is used today (Yang et. Al, 2017). There are two distinctions of Chinese Bupleurum, Bei Chai Hu (Bupleurum chinensis), which is from Northern China, and Nan Chai Hu, which is from Southern China (Bupleurum scorzoneraefolium) (Penner, 2017). Bupleurum is popular in Korean and Japanese Medicine as well, although it is used in smaller amounts (Tierra, 1988). In Japan, Bupleurum is known as “Saiko”, and is used in a well-known formula called Sho-Saiko-To (which is the Xiao Chai Hu Tang formula in Chinese medicine). It is not commonly used in Ayurvedic Medicine but is considered anti-Kapha, anti-Pitta, and pro-Vata (Frawley, 1988).

The medicinal part of the plant used is the root, which is considered slightly toxic. It is often combined with other herbs and used in amounts of 3-15 grams, although there are records of using up to 60 grams of Bupleurum in formulas (Chen, 2004). It primarily enters the Gallbladder and Liver meridians but is said to enter the Pericardium and Triple Warmer meridians as well (Tierra, 1988). Its energetic flavor is Bitter and slightly Pungent according to the Shen Nong Ben Cao Jing. It is also considered slightly aromatic and is ascending and dispersing in action (Chen, 2004).

Since Bupleurum is Cold, Bitter, and Pungent, it is not recommended in cases of Liver Yin deficiency with Heat or Liver Wind or Yang Rising. This is because prolonged use of Bupleurum is said to “injure the Yin” (Tierra, 1988).  Due to Bupleurum’s rising and dispersing energy, it can cause excess Liver energy to go to the head and cause headaches and anger outbursts. It is also not recommended for pregnancy or breast-feeding due to a lack of research.

About 74 constituents have been isolated from Bupleurum over the past few decades. The active constituents in Bupleurum that have been discovered include triterpene glycosides, saikosides, essential oils r-heptalactone and r-decalactone, flavone, coumarin, and organic acids (Yang et. Al, 2017). The active principles of Bupleurum are the triterpene glycosides, specifically saikosides or saikosaponins (Chen, 2004). Bupleurum’s volatile compounds such as essential oils are believed to be the primary compounds responsible for its anti-fungal and anti-inflammatory activities (Yang et. Al, 2017).

In regard to Chinese herbal categorization, Bupleurum is listed as an Herb that can Release Exterior Wind-Heat, although usually not the first herb that a Chinese herbal practitioner would select to release the Exterior. Signs of Exterior Wind-Heat are primarily that of an exogenous pathogenic factor and can include symptoms of a common cold or flu such as chills, fever, sore throat, runny nose, possible sweating, achy body and limbs, and fatigue. Modern studies are proving that Bupleurum has antibiotic activity against bacterial infections such as b-hemolytic streptococcus, vibrio cholera, mycobacterium tuberculosis, leptospira, some forms of influenza, and poliomyelitis. In a Western study of 666 patients, a formula consisting of Bupleurum, Fang Feng (Shaposhnikova root), Sheng Jiang (Fresh Ginger root), Chen Pi (Tangerine Peel), and Gan Cao (Licorice root) was found to have a 79% effective rate against colds and flus. In another study involving 1,005 patients, Bupleurum was used alone to treat cough, with an 85.5% effective rate. One study shows that Bupleurum stimulates humoral and cellular immunity in mice, which supports that Bupleurum is effective in building immunity against External pathogenic factors (Chen, 2004). Bupleurum’s effect on Exterior pathogenic factors become clearer through the isolation and active research of its active constituents. Saikosaponins A and D were isolated in water and found to stimulate B and T cells as well as macrophage activity in mice, with Saikosaponin A having stronger activity (Yang et. Al, 2017). Despite not being primarily used to Release Exterior Wind-Heat, modern studies give Bupleurum promising results for antibacterial and antiviral use.

A more common use of Bupleurum in Chinese Medicine is to regulate Liver Qi, especially in cases of Liver Qi Stagnation (Chen, 2004). Bupleurum enters both the Liver and Gallbladder channels, which are a husband-wife pair according to the Zang-Fu Organ theory of Chinese Medicine. Some symptoms of Liver/Gallbladder imbalances include anger, irritability, depression, hypochondriac pain, chest constriction, irregular menses, stress, sighing, tight neck and shoulders, and jaundice (Cannon, 2016). These symptoms are common results of Liver Qi Stagnation, since the Liver oversees regulation of the free flow of Qi. Bupleurum disperses Liver Qi by promoting blood circulation of the Liver (Chen, 2004). A term often used to describe Bupleurum’s action is “dredging” the Liver, which means to excavate and remove sediment and debris from the area. This dredging can open the patient to emotional outbursts; this is because the Liver is highly susceptible to emotional imbalances which can either cause or lead to Liver Qi Stagnation. Once dredged, the “flood gates” open and the Stagnation clears, moving old pent-up emotions that may have been stored in the organs and tissues of the body (Tierra, 1988).

One formula that is specifically indicated for Liver Qi Stagnation with emotional distress is Xiao Yan San, also known as Free and Easy Wanderer formula, a formula from the Taiping Huimin Heji Jufang c.1000-1120 (Welden, 2021). This formula uses Bupleurum as the primary herb to move Liver Qi Stagnation. Bupleurum and Bai Shao Yao (White Peony root) are used as a Dui Yao to move Liver Qi; Bai Shao Yao balances the actions of Bupleurum as it protects the Yin of the Liver and is more nourishing than Bupleurum (Chen, 2004).

Another formula for Liver Qi Stagnation is Si Ni San, which also uses Bupleurum and Bai Shao Yao as a Dui Yao combination. This formula is useful when the extremities are cold because the Liver Qi is stagnant, trapping the Heat in the Liver and not extending it to the extremities. Since Bupleurum has an ascending and dispersing energy, it helps to free the Liver Qi to warm the extremities, along with other dispersing herbs in the formula.

The formula Long Dan Xie Gan Wan, also known as “Gentiana Drain the Liver Pill” is used to clear Liver Heat. Bupleurum is one of the chief herbs in this formula because of its ability to dredge the Liver. It is also in the Shu Gan Wan formula for the same reason.

Western biomedicine confirms that Bupleurum produces beneficial effects on the liver as described in Chinese Medicine. Entering the Liver and Gallbladder channels and moving Liver Qi Stagnation can be scientifically compared to Bupleurum’s choleretic and hepatoprotective abilities (Wang, 2003). Being choleretic means that Bupleurum can stimulate bile flow; both the liver and gallbladder are anatomically responsible for bile production and flow. Li Dan Pian is a formula with Bupleurum as a chief herb to increase bile flow, used specifically for Gallbladder disorders such as gallstones and gallbladder inflammation (Tierra, 1988).

Chang et. Al outlines the positive effects of saikosaponins in protecting against liver injury, increasing antioxidant levels of glutathione and superoxide dismutase, and decreasing high liver enzymes such as ALT, AST, ALP, and bilirubin in laboratory mice (Chang et. Al, Oct. 2021). In an earlier study, two flavonoids of Bupleurum, Rutin and Narcissin, were isolated and specifically shown to have hepatoprotective action (Gevrenova, 2015). Narcissin, a flavonoid found in Bupleurum, shows antioxidant activity in liver cells similar or even stronger than silymarin, another hepatoprotective substance derived from Milk Thistle seeds (Gevrenova, 2015).

In another rat study, Bupleurum’s ability to reduce liver fibroids are claimed to be due to its anti-hyperlipidemic action (Yang et. Al, 2017). Being anti-hyperlipidemic also means that Bupleurum can positively effect triglyceride levels and moderately reduce high cholesterol and possibly fatty liver disease (Chen, 2004).

Furthermore, Bupleurum’s liver-protective benefits show promise against viral infections such as hepatitis, which tend to affect the liver. Saikosaponins A, B, C, and D are credited with immunomodulating effects which have been shown to inhibit hepatitis viruses in the early stages of their life cycle (Lin et. Al, 2015). Saikosaponin B has particularly been shown to “inhibit viral particles and prevent viral attachment and cellular entry in cultured human hepatocytes” (Lin et. Al, 2015).

Another one of Bupleurum’s main uses in Chinese Medicine is to Harmonize the Interior and Exterior. The Gallbladder channel is associated with the Shao Yang level of the Six Levels in which a disease may be present as discussed in the Shang Han Lun. The Shao Yang level is indicated by “alternating” symptoms such as alternating chills and fever, diarrhea and constipation, and chronic, lingering diseases that come and go (Tierra, 1988). This level indicates that an Exterior pathogen has lodged its way into the body, wavering between the Exterior and Interior of the body. The Shang Han Lun confirms this with the saying, “Tai Yang opens, Yang Ming closes, and Shao Yang is the pivot between Tai Yang and Yang Ming” (Wiseman et. Al, 1998). Bupleurum is most often used when a disease is moving between the Yang levels (Tai Yang, Yang Ming, and Shao Yang). Even though Bupleurum is classified as an herb that Releases Exterior Wind-Heat, it is more commonly used to Harmonize the Exterior and Interior. One study defines this Harmonizing aspect as the saikosaponin’s ability to support autophagic regulation, therefore maintaining cellular homeostasis and genome stability (Law et. Al, 2014).

One Classic Chinese formula used to Harmonize the Exterior and Interior is called Xiao Chai Hu Tang (Minor Bupleurum Formula), which contains Bupleurum as one of the chief herbs.  This formula was presented by Cheng Wuji in the Shang Han Mingli Lun, published around 1144 (Welden, 2021). Bupleurum and Huang Qin (Scutellaria root) are combined as a Dui Yao to Harmonize the Exterior and Interior: Bupleurum releases the Exterior while Huang Qin clears Heat from the Interior (Chen, 2004). Xiao Chai Hu Tang also addresses cases that appear both Excess and Deficient, since it has Clearing and Dispersing herbs along with Tonifying herbs such as Ren Shen (Asian Ginseng root) and Da Zao (Jujube date). On the other hand, Da Chai Hu Tang (Major Bupleurum Formula) works to treat Exterior Pathogens wavering between the Shao Yang and Yang Ming levels, manifesting as excessive Heat in the body. Its anti-pyretic action has been confirmed in studies exploring Bupleurum’s pharmacological effects (Law et. Al, 2014).

Another formula useful for Shao Yang syndromes is Chai Ge Jie Ji Tang, which is used to eliminate a lingering external pathogen such as a cold or flu (Chen, 2004). This formula also has the Dui Yao combination of Bupleurum and Huang Qin along with the Exterior-releasing herb, Ge Gen (Kudzu root). In addition, Bupleurum appears to combine well with Qiang Huo (Notopterygium Incisum root) in treating malaria and febrile diseases, which often display Shao Yang symptoms of alternating fever and chills, diarrhea and constipation, and lingering between an acute and chronic condition.

Bupleurum also has anti-inflammatory and analgesic properties. It was first shown by Ma et al. that saikosides from Bupleurum have powerful anti-inflammatory effects (Ma et. Al, 2016). Saikosaponins have sedative actions and Bupleurum can be used as smooth muscle relaxant (Teegarden, 1988). An antispasmodic Chinese herbal formula, Yi Gan San, is said to calm “Liver Wind” (observed clinically as tremors, spasms, and tics) and tonify Liver Blood and Qi (Tierra, 1988).

Another condition Bupleurum is used for is in cases of organ prolapse due to sinking Central Qi. For this purpose, Bupleurum is only needed in small amounts such as 3 grams and is used for its ascending and dispersing direction (Chen, 2004). One formula used to tonify Spleen Qi and Raise Sinking Qi is Bu Zhong Yi Qi Wan (Tonify the Middle and Augment the Qi Pill), which appears in Piwei Lun (Treatise on the Spleen & Stomach) written by Li Dongyuan sometime during 1180-1251 (Welden, 2021). In Chinese Tonic Herbs, Bupleurum is said to pull fresh Qi to the upper part of the body, which is another way to describe its ability to raise the Yang Qi (Teegarden, 1985). In Bu Zhong Yi Qi wan, Bupleurum is used with another Yang-raising herb, Sheng Ma (Chinese Black Cohosh) to raise sinking Qi which can present as prolapsed organs or hemorrhoids.

Bupleurum is included in several formulas that act on the Blood, although by itself Bupleurum is not considered a Blood tonic. In Chinese Medicine, the Liver plays a key role in menstruation since it is said to store the Blood. Therefore, Bupleurum helps to regulate menstrual irregularities through its action on the Liver. It is best combined with Blood tonic herbs such as Dang Gui and Bai Shao Yao, along with Blood-invigorating herbs like Xiang Fu (Chen, 2004). One may also wish to include Mu Dan Pi in these combinations for its ability to Clear Heat and Cool the Blood, which may be necessary depending on the pattern presented (Chen, 2004).

Xue Fu Zhu Yu Tang, Dispel Stasis in the Blood Palace Decoction, is a formula that works to Invigorate Blood. Chai Hu is included because of its ability to regulate Liver Qi since Qi moves the Blood.

            Although not listed as a classical formula, Dr. Chen recommends using Bupleurum with Chuan Xiong, Xiang Fu, and Bai Shao for migraine headaches affecting the Shao Yang (Gallbladder and Triple Warmer) regions of the head (Chen, 2004). He also reports that Bupleurum can be used for eye problems due to Liver Fire Rising, since the Liver opens to the Eyes through the Blood. These issues would present as red, swollen, and painful eyes. For this purpose, Chen suggests using Bupleurum, Huang Qin, Fang Feng, Zhi Zi and Jue Ming Zi (Chen, 2004).

Some less common uses of Bupleurum include strengthening the Stomach and Intestines and strengthening the Lungs, head, sense organs of the face, and limbs. Modern studies support these ideas; for example, one study examined the apoptotic effects of Saikosaponin D in human lung cancer cells (Hsu et. Al, 2004). This suggests promise for further studies on Bupleurum’s anti-cancer benefits. Another study gives truth to the notion that Bupleurum can strengthen the intestines: polysaccharides present in Bupleurum were extracted for use on lab mice to study Bupleurum’s effects on gut microbiota and inflammation. Although the mechanisms are unclear, Bupleurum-extracted polysaccharides supported higher diversity of gut protective microflora (Feng et. Al, 2019). Bupleurum is not primarily used to strengthen the Stomach and Intestines, but studies like these show promise in expanding our knowledge of Bupleurum’s medicinal properties.

As noticeable in the formulas above, Bupleurum is often used with other herbs: when used on its own, Bupleurum can be very drying to the body’s Yin or stimulate emotional flare-ups when the Liver is dredged. It works well as a Chief herb in formulas for Liver Qi Stagnation. It also can work as a Minister herb to help Clear Heat, though not its main function, due to its Cool energy. Lastly, Bupleurum can work as an Assistant herb to direct the herbs upward and outward and/or to the Liver.

There are several different preparation methods for Bupleurum. When fried in vinegar, Bupleurum is more effective in regulating Liver Qi for hypochondriac pain, abdominal pain, and menstrual cramps since vinegar has a particular action on the Liver. One study of using raw and vinegar-fried Chai Hu on liver injury-induced mice showed that the vinegar-fried Chai Hu had better hepatoprotective action than its raw form (Yang et. Al, 2017). Dry-roasted Bupleurum is less cooling than its raw form, but supposedly works better on raising the Yang Qi in cases of prolapse (Penner, 2017). Raw Bupleurum has an ascending and dispersing action, which is better used in Releasing the Exterior and reducing fever (Chen, 2004). Although not particular to Bupleurum itself, the Long Dan Xie Gan Dan formula (which contains Bupleurum) was traditionally rolled in a cinnabar coating, with the idea that the cinnabar would help to calm the Shen (Welden, 2021).

Even though herbs are considered natural, there is good reason to use caution with any herbal substance and Bupleurum is no exception.  An interesting trait of Bupleurum’s dual-sided nature is in its capacity to treat or harm the Liver. In small amounts, it is medicinal for the Liver, yet in large amounts can be hepatotoxic (Yang et al., 2017). The adage “the poison is in the dosage” applies here, if not to all medicinal substances.

When treating illness, it is essential not to trap the disease inside or vent the body to the point of injury, which are two issues that should be treated differently based on whether the disease is more Internal or External. Therefore, it is cautioned not to use Bupleurum for conditions presenting with only External symptoms, since it may end up bringing the disease more inward and become more difficult to treat.

Bupleurum is an essential ally in the practice of Chinese Herbal Medicine and there is no herb quite like it. Curiously, Bupleurum entertains a variety of medicinal applications that can be hard to peg into one definite action. This is what gives Bupleurum its strength: not only its wide range of applicability, but its ability to harmonize contradicting characteristics of disease. With more clinical studies and research being done, Bupleurum is earning the respect and understanding it deserves.  Bupleurum continues to hold an essential role in Chinese herbal medicine, just as it has for thousands of years.  

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