Chinese thoroughwax

Other Names

Bei Chai HuBeichaihuBeichaihu (Northern Chinese Thorowax Root)BupleuriBupleuri RadixBupleurumBupleurum chinenseBupleurum chinense DC.Bupleurum chinense f. chiliosciadiumBupleurum chinense f. octoradiatumBupleurum chinense f. pekinenseBupleurum chinense f. vanheurckiiBupleurum chinense var. octoradiatumBupleurum chinense var. vanheurckiiBupleurum chinensisBupleurum falcatumBupleurum falcatum L.Bupleurum falcatum subsp. scorzonerifoliumBupleurum falcatum var. ensifoliumBupleurum falcatum var. scorzonerifoliumBupleurum rootBupleurum scorzonerifoliumBupleurum scorzonerifolium Willd.Bupleurum sinensiumBupleurum togasiiBupleurum vanheurckiiBuplèvreBuplèvre à Feuilles de ScorsonèreBuplèvre à Longues FeuillesBuplèvre ChinoisBuplèvre LigneuxChai HuChaicaoChaihuChi HuChinese BupleurumDixunFuhuGucaoHare's EarHare's Ear RootNan ChaihuNanchaihuNanchaihu (Southern Chinese Thorowax Root)North BupleurumRadix BupleuriSaikoShancaiShihoShrubby Hare's EarSi HoSickle-leaf Hare's EarSickle-leaved Hare's EarSickleleaf Hare's EarSouth BupleurumThoroughwaxThorow WaxThorowax

Synopsis

Chinese Thoroughwax (Bupleurum chinense DC.): A Comprehensive Reference

1. Identity and Botanical Characterization

Names and Taxonomy

Bupleurum chinense (Chai Hu; Chinese: 柴胡; pinyin: chaí hú; also known as Thorowax) is a plant of the family Apiaceae. English vernacular names include Chinese thoroughwax and hare's ear root, the latter evoking the plant's leaf shape resembling a hare's ear. In Japanese it is referred to as saiko, reflecting its role in Kampo formulations such as sho-saiko-to. The Korean name is si ho, similarly tied to East Asian medicinal traditions.

The genus name Bupleurum originates from the Greek terms bous (ox) and pleuron (rib), alluding to the ribbed structure of the plant's roots or stems. The Chinese name chai hu translates to "kindling of the barbarians," with the exact origin remaining unclear despite its long-standing use in traditional contexts. The plant belongs to the Apiaceae (the carrot or parsley family), a botanical family famous for its aromatic and medicinal members like angelica, fennel, and lovage.

Chinese thoroughwax is often called bupleurum, referring to the scientific naming of the species Bupleurum chinense and Bupleurum falcatum. As described in the Chinese Pharmacopoeia, the roots of Bupleurum chinense DC. and B. scorzonerifolium Willd. are the herbal materials that compose Chaihu (Radix Bupleuri), a well-known TCM herb. The root of B. chinense DC. is considered the genuine Chaihu, but other species have been included in the Pharmacopoeia of the People's Republic of China since 1963, including bei Chaihu and nan Chaihu (referring to northern and southern thorowax root). B. falcatum is used in Japan.

Botanical Description

Bupleurum chinense DC. is a perennial herbaceous plant characterized by erect stems up to 85 cm tall, broadly linear-lanceolate leaves measuring 4–7 cm in length, and compound umbels with bright yellow flowers that bloom from July to September. The plant features a conical, taupe-colored root, 6–20 cm long, which serves as the primary medicinal part, known as Radix Bupleuri. Native to East Asia, particularly China, it thrives in grasslands, sunny slopes, and stream banks at altitudes of 100–2700 m, and is widely cultivated in China, Japan, and Korea for its therapeutic properties.

The genus Bupleurum includes approximately 200 species that are widely distributed in the Northern Hemisphere, Eurasia, and North Africa. There were approximately 36 Bupleurum species and varieties in different districts and markets due to the slightly different morphological appearance of Bupleurum plants, including B. longiradiatum Turcz. with toxic ingredients and B. hamiltonii Balak with very little active constituents.

Pharmacopoeial Recognition and Quality Standards

The total amounts of saikosaponins a and d are used as the indicator compounds to characterize the quality of this plant, with minimum contents of 0.3% in the Pharmacopoeia of the People's Republic of China. Saikosaponin a (SSa) and saikosaponin d (SSd) serve as the chemical standards used in the Chinese Pharmacopoeia 2020 edition to evaluate the quality of Radix Bupleuri. Studies have shown significant variation in saikosaponin content, the key bioactive components of Radix Bupleuri, with levels differing up to tenfold among plants from different origins.

Common Forms and Preparations

The roots, known as Radix Bupleuri, are harvested for medicinal use after the plant is a few years old. Harvesting occurs in spring and autumn, removing stems, leaves, and silt, and drying. For general use, many practitioners recommend 1.5–6 grams of dried bupleurum root in a decoction, or 3–12 ml of a 1:2 extract; the herb is also available in capsule and tincture forms. Generally 500–2,000 mg bupleurum dry root are taken three times daily in capsules; traditionally, and in some clinical studies, bupleurum was prepared as a tea in which the root is decocted or cooked for hours before use.

2. Traditional and Historical Use

Origins in Chinese Medicine

Bupleurum is a traditional Chinese herb dating back to the first century BC and is one of the most commonly used herbs in traditional Chinese medicine. The dried root of Bupleurum chinense DC. is initially recorded in "Shennong's Classic of Materia Medica" around 200 AD. With a 2,000-year medicinal history, Radix Bupleuri (Chai Hu in Chinese) is believed to be one of the most important herbal medicines in China.

Only the roots of the Bupleurum were used in medicine before the Ming Dynasty. The effect of "robbing liver yin" of Bupleuri Radix had been widely reported since the Ming and Qing Dynasties. The first recorded medicinal use of Bupleurum appeared in a Chinese medical text that dates to the close of the Eastern Han Dynasty in the 3rd century AD; this volume, regarded as the "Father of Formula," contains 269 herbal formulas, one of which is Xiao Chai Hu Tang.

Traditional Therapeutic Indications

In traditional Chinese medicine, Bupleurum chinense has been utilized for over 2,000 years to treat a range of conditions including fever, inflammation, hepatitis, malaria, menstrual disorders, and emotional imbalances such as depression, often as a liver tonic that harmonizes qi and yang. Bupleurum has been used in Traditional Chinese Medicine for thousands of years to help relieve numerous conditions, most particularly infections with fever, liver problems, indigestion, hemorrhoids, and uterine prolapse.

Radix Bupleuri has been used in traditional Chinese medicine for over 2,000 years with functions of relieving exterior syndrome, clearing heat, regulating liver-qi, and lifting yang-qi. The main pharmacological effects of Bupleuri Radix are soothing the liver and relieving depression, evacuating fever, and elevating "Yang Qi." B. chinense DC., commonly known as Bupleuri Chinense Radix, is often used to treat typhoid fever, while B. scorzonerifolium Willd. is often used to clear liver heat, so they exhibit distinct clinical uses.

Key Traditional Formulas

Xiao Chai Hu Tang (also called XCHT, Sho-saiko-to, or minor Bupleurum decoction), a herbal formula, was first recorded in the Treatise on Febrile Disease (Shang Han Lun) in about 280 AD. The ingredients of the Xiao Chai Hu Tang formula are Chai Hu (Bupleuri Radix), Ban Xia (Pinelliae Tuber), Sheng Jiang (Zingiberis Rhizoma), Da Zao (Zizyphi Fructus), Ren Shen (Ginseng Radix Rubra), Huang Qin (Scutellariae Radix), and Gan Cao (Glycyrrhizae Radix). Sho-saiko-to is a Japanese kampo or traditional herbal medicine formula based on the traditional Chinese formula xiao-chai-hu-tang, in English called minor bupleurum formula; bupleurum makes up 16% of the formula.

Bupleurum chinense DC.–Paeonia lactiflora Pall. (Chaihu-Baishao) as a classic herb pair were frequently used to enhance therapeutic efficacy in many anti-depression TCM prescriptions such as Xiaoyao San, Sini San, and Chaihu Shugan San. Bupleurum forms an integral part of many Kampo medicines (the Japanese adaptation of traditional Chinese medicine), including shosaikoto, daisaikoto, saikokeishito, hochuekkito, saibokuto, and others.

Use in Japan and Korea

Bupleurum is also a staple in Japanese Kampo medicine in the formula "Sho-Saiko-To," used to address liver concerns. Radix Bupleuri has been used as a traditional medicine for more than 2,000 years in China, Japan, Korea, and other Asian countries. Bupleurum has been used as a Jie Yu (depression-relieving) medicine in China, Japan, the Republic of Korea, and other Asian countries for centuries.

3. Key Constituents and Active Compounds

Overview of Phytochemical Classes

In the past few decades, approximately 74 compounds have been isolated from Radix Bupleuri, including essential oils, triterpenoid saponins, polyacetylenes, flavonoids, lignans, fatty acids, and sterols. In addition to saikosaponins, Radix Bupleuri contains volatile oils, polysaccharides, polyacetylenes, lignans, flavonoids, fatty acids, sterols, coumarins, alkaloids, and many other active components, which exert various effects such as anti-inflammatory, antioxidant, anti-tumor, anticancer, antidepressant, antimicrobial, antifungal, hepatoprotective, and immunomodulatory activities by modulating multiple signaling pathways.

Triterpenoid Saponins (Saikosaponins)

In recent years, over 100 different triterpenoid saponins have been isolated from Radix Bupleuri; among them saikosaponin a (SSa), saikosaponin d (SSd), saikosaponin c (SSc) and saikosaponin b2 (SSb2) are believed to be responsible for the most pharmacological activities of Radix Bupleuri. Saikosaponins are oleanane-type triterpenoid saponins and divided into seven types according to different aglycones. Saikosaponins are the major bioactive constituents of B. chinense DC., and their biosynthesis has been more intensively studied than any other metabolic process or bioactive constituent in Bupleurum.

Pharmacokinetic studies have demonstrated that the major bioactive compounds (saikosaponins a, b2, c, and d) were absorbed rapidly in rats after oral administration of the extract of Radix Bupleuri. Levels of saikosaponins vary widely between species (i.e., B. falcatum 2–8% and B. chinense 1.7 [percent range] according to published pharmacological data).

Flavonoids

Flavonoids in Bupleurum are credited with hepatoprotective actions and include rutin and narcissin; narcissin displays an antioxidant action in liver cells that is similar or stronger than that of silymarin, and it is capable of reducing elevated lactate dehydrogenase and malondialdehyde.

Polysaccharides and Other Constituents

After chemical profiling, several groups of secondary metabolites have been characterized with relevant biological activity: triterpene saponins (saikosaponins), lignans, essential oils, and polysaccharides. The polysaccharides are linked to immunomodulatory and anti-inflammatory activity, while the volatile oil components contribute to the herb's documented antipyretic properties.

4. Established Mechanisms of Action

Anti-inflammatory Mechanisms

Bupleurum contains constituents known as saikosaponins that appear to account for much of the medicinal activity of the plant; test tube studies have shown that the sho-saiko-to combination can increase production of various chemicals (cytokines) that immune cells use to signal one another, and test tube studies have also found that saikosaponins are anti-inflammatory. In screening for in vitro effects of saikosaponins on cellular systems generating cyclooxygenase (COX) and lipoxygenase (LOX) metabolites, most saikosaponins showed a significant effect, with the action being more marked on LOX metabolite LTC4; these data support the inhibition of arachidonic acid metabolism as one of the biochemical mechanisms underlying the putative anti-inflammatory activity of saikosaponins.

Saikosaponin A mediates the inflammatory response by inhibiting the MAPK and NF-κB pathways in LPS-stimulated macrophage cells; saikosaponin-d suppresses the expression of cyclooxygenase-2 through the phospho-STAT3/HIF-1α pathway in hepatocellular carcinoma cells.

Membrane-Targeting Effects of Saikosaponins

Some of the isolated secondary metabolites from Bupleurum act directly on the biomembrane; both saikosaponins and sterol glycosides are amphiphilic molecules that function as detergents and exist mostly in their monodesmosidic forms; the monodesmosides are anchored with their lipophilic moiety in the membrane bilayer after complexing with cholesterol, resulting in loss of membrane integrity and fluidity with subsequent leakage of polar molecules out of cells; many saponins are therefore cytotoxic against a wide range of cells, including cancer cells, bacteria, and fungi.

Hepatoprotective Mechanisms

Animal research suggests that Bupleurum can protect the liver from carbon tetrachloride, tert-butyl hydroperoxide, and acetaminophen, and may reduce fibrotic changes in the liver, improve obstructive jaundice, and decrease hepatocarcinogenesis in chronic liver inflammation; bupleurum exerts a hepatoprotective effect in galactosamine-induced liver inflammation in mice, significantly reducing aspartate transaminase (AST) and alanine transaminase (ALT).

Antidepressant Mechanisms

The antidepressant potential of the herbal combination of Bupleurum chinense DC. (Chaihu) and Paeonia lactiflora Pall. (Baishao) has been extensively studied; it works mainly through relieving oxidative stress, regulating the HPA axis, and protecting neurons.

Immunomodulatory Mechanisms

Saikosaponin D (SSD), a triterpenoid saponin extracted from Bupleurum, exhibits extensive pharmacological properties, including anti-inflammatory, antioxidant, anti-apoptotic, anti-fibrotic, and anti-cancer effects. The mechanisms underlying these pharmacological actions involve inflammation, oxidative stress, immune modulation, autophagy, and apoptosis, thereby influencing the progression of numerous diseases.

5. Scientific Evidence by Area of Use

5.1 Liver Disease and Hepatoprotection

Although bupleurum is used in traditional Chinese medicine to treat liver diseases, human data are largely lacking. The most extensively studied preparation in clinical settings is the multi-herb formula Xiao Chai Hu Tang / Sho-saiko-to rather than bupleurum as a single ingredient.

Chronic Hepatitis B — Cochrane Review: A Cochrane review includes 10 randomised clinical trials with 934 participants; these trials did not provide data on patient-centred outcomes including all-cause mortality, proportion of participants with serious adverse events, health-related quality of life, or hepatitis B-related morbidity. The evidence showed a beneficial effect of Xiao Chai Hu Tang formula on the proportion of participants with detectable HBV-DNA, but this surrogate outcome is not validated and the certainty of the evidence was very low.

Hepatocellular Carcinoma Prevention: Sho-saiko-to has been shown in animal models to prevent liver injury and promote liver regeneration by inhibiting oxidative stress on lipid peroxidation in hepatocytes and hepatic stellate cells, and in human trials to prevent the progression of cirrhosis to hepatocellular carcinoma (HCC); one prospective study of 260 patients also found that it increased the survival of those with chronic viral hepatitis by reducing progression to HCC.

Phase II Trial in Hepatitis C: A Phase II trial at Memorial Sloan Kettering Cancer Center showed that sho-saiko-to may improve liver pathology in patients with HCV who are unable or choose not to receive interferon therapy; in this open-label trial, 24 subjects were given 2.5 g granulated powder, three times daily, for 12 months.

Pediatric Hepatitis B: A study of the effect of Sho-saiko-to on HBeAg clearance rate in fourteen children with chronic hepatitis B virus infection found that seven of fourteen patients (50.0%) became HBeAg negative in an average observation period of 0.47 years (0.2–0.9 years); the annual seroconversion rate in the Sho-saiko-to treated group was apparently higher than the natural annual rate of 22.7% in 22 untreated patients, suggesting that Sho-saiko-to may promote clearance of HBeAg.

Evidence assessment: The human evidence for bupleurum-containing formulas in hepatitis is preliminary and methodologically limited. The Cochrane review characterizes available RCT evidence for Xiao Chai Hu Tang as very low certainty. Single-arm and prospective observational studies show signals of potential benefit but cannot establish causality. Studies generally examine multi-herb formulas, not bupleurum as an isolated agent.

5.2 Depression and Mood

The incidence of depression has been steadily rising; Chaihu (Bupleurum) has been traditionally used for liver conditions such as hepatitis, liver inflammation, liver fibrosis, and liver cancer, as well as for depression-relieving purposes in Asia for centuries. Bupleurum chinense serves as the sovereign medicinal in many antidepressant compound preparations.

Although a meta-analysis suggests Bupleurum chinense herbal formulas may help reduce depression severity, the evidence was considered to be of low quality. The evidence on Bupleurum chinense for depression is considered low quality by Memorial Sloan Kettering Cancer Center's integrative medicine service. In animal studies, Bupleuri Radix improved depression-like behaviors in chronic unpredictable mild stress (CUMS) rats, and the lower polar fraction of Bupleuri Radix had the strongest antidepressant activity compared to other fractions.

Evidence assessment: Current evidence for bupleurum (whether alone or in formulas) for depression consists primarily of animal models and low-quality RCTs, almost all of which test multi-herb formulations rather than bupleurum as a single agent. Independent human RCT evidence is insufficient.

5.3 Antipyretic (Fever Reduction)

Oral decoctions of bupleurum, subcutaneous injection of the root extract, and oral saikosaponins have shown antipyretic effects in rats and rabbits; nasal gel and nasal spray made from the essential oil of bupleurum reduced fever in rats and rabbits in a dose-dependent manner. Although bupleurum is used in traditional Chinese medicine to reduce fever, there are no clinical data to back this claim.

Evidence assessment: Preclinical (animal) evidence supports an antipyretic effect; human clinical evidence is absent.

5.4 Anti-inflammatory Effects

Laboratory studies show that components of bupleurum interfere with the processes that cause inflammation; human studies are needed. Multiple in vitro and animal studies demonstrate inhibition of NF-κB, MAPK, and COX/LOX pathways. No adequately powered human RCTs have specifically tested the anti-inflammatory effects of bupleurum root as a single ingredient.

5.5 Antiviral Activity

In in vitro studies, bupleurum inactivated enveloped viruses, including measles and herpes, but had no effect on nonenveloped viruses (e.g., polio); saikosaponins inhibited coxsackie B virus, and saikosaponin b2 inhibited the human coronavirus responsible for SARS; in vitro experiments have also shown that saikosaponin D suppresses enterovirus A71 infection by inhibiting autophagy.

One human study compared the effectiveness of an herbal preparation containing Bupleurum saponin with the common antiviral flu drug Tamiflu, finding the bupleurum decoction to be 93.3% effective at treating influenza A (H1N1) with no adverse effects; however, more human research is needed. Bupleurum may have antiviral activity, but clinical trials have not been conducted for the common cold.

Evidence assessment: Antiviral activity is supported by laboratory and cell-culture studies. The single human influenza study is preliminary and does not meet current standards for robust clinical evidence. Further controlled trials are required.

5.6 Immune Modulation

Clinical studies have shown that Bupleuri Radix has also been used for anti-virus infection, anti-acute radiation injury, anti-ulcer effects, reducing blood lipids, inducing serum interferon, and enhancing immune function. Peripheral blood mononuclear cells from both HBeAg- and anti-HBe-positive patients generated significantly increased IFN-gamma and antibody production in culture containing Sho-saiko-to (TJ-9) in a dose-dependent manner; these results indicate that TJ-9 is able to modulate both cellular and humoral immune responses specific for HBV-associated antigens.

Evidence assessment: Immune modulation evidence is largely mechanistic (in vitro, ex vivo) or derived from multi-herb formula studies. Isolated bupleurum's effects on human immunity remain incompletely characterized.

5.7 Antitumor / Anticancer

Test tube studies have found that saikosaponins can inhibit growth of liver cancer cells. Crude extracts and pure compounds isolated from Radix Bupleuri exhibited anti-inflammatory, anticancer, antipyretic, antimicrobial, antiviral, hepatoprotective, neuroprotective, and immunomodulatory effects in preclinical settings.

Evidence assessment: All anticancer evidence is currently preclinical (cell-culture and animal studies). There are no published human clinical trials establishing that bupleurum root or saikosaponins treat or prevent cancer in humans.

5.8 Hashimoto's Thyroiditis

A placebo-controlled randomized trial cited in the WebMD/Drugs.com literature (Meng X, Liu S, Deng X, et al., "Clinical efficacy of Bupleurum inula flower soup for immune damage intervention in Hashimoto's thyroiditis: A placebo-controlled randomized trial," Frontiers in Pharmacology 2022;13:1049618) investigated bupleurum-containing preparations in thyroid autoimmunity, but this study tested a multi-herb formula and conclusions about bupleurum alone cannot be drawn from it.

6. Body Systems and Health Areas

Hepatobiliary system: The root of B. chinense, known as Radix Bupleuri, is used in traditional Chinese medicine and has a large number of uses including application for liver issues. Preclinical evidence suggests hepatoprotective activity; clinical evidence (primarily for multi-herb formulas) is limited and of low to very low certainty.
Immune system: Certain species of the genus have long been used as antiphlogistic, antipyretic, and analgesic agents in traditional folk medicine. Saikosaponins have demonstrated immunomodulatory effects in preclinical studies.
Central nervous system / Mood: It is commonly used to treat depression by soothing the liver and resolving melancholia. Evidence in humans is preliminary and of low quality.
Cardiovascular / Metabolic: Among the saikosaponins isolated from Bupleurum falcatum L., saikosaponins a and d had metabolic actions as well as anti-inflammatory action, including elevation reduction of plasma levels of cholesterol, triglycerides, and phospholipids by cholesterol feeding.
Respiratory system: Saikosaponin A reduced antigen challenge-induced bronchoconstriction in experiments conducted on guinea pigs. No human respiratory trial data are available.

7. Dosage Forms and Dosages Reported in Studies

Traditional and clinical doses of bupleurum in decoction range from 1–4 grams per cup of water, three times daily; 500–2,000 mg dry root taken three times daily in capsule form has also been reported. Sho-saiko-to formula is typically given in capsules (1.8–2.5 grams) three times per day in clinical use.

In the Memorial Sloan Kettering Phase II open-label trial of sho-saiko-to in HCV patients, 24 subjects were given 2.5 g granulated powder, three times daily, for 12 months.

For general use, many practitioners recommend 1.5–6 grams of dried bupleurum root in a decoction, or 3–12 ml of a 1:2 liquid extract.

In toxicological animal studies, dose-dependent hepatic effects have been observed at various doses: a rat toxicity study investigated three dosages of B. chinense—50, 150, and 300 mg/kg—on hepatic function, renal function, and the metabolism of lipids and carbohydrates. A dose-dependent hepatic tissue damage was associated with increased liver enzymes and visible hepatic tissue damage; bupleurum at a dose of 1 mg/kg for 4 or 8 weeks was also shown to increase liver enzymes (AST and ALT), immunoglobulins, and antinuclear antibody in the blood.

No standardized, clinically validated dosing regimen for bupleurum as a single ingredient has been established in Western regulatory contexts, and doses in available published studies primarily refer to traditional multi-herb decoctions.

8. Safety Considerations and Interactions

General Tolerability

When taken by mouth, bupleurum is possibly safe; it has been used as part of a Japanese herbal formula called Sho-saiko-to for up to 5 years and is usually well-tolerated; side effects might include nausea.

Hepatotoxicity

Phytochemical studies demonstrated that crude extracts and pure compounds isolated from Radix Bupleuri exhibited anti-inflammatory, anticancer, antipyretic, antimicrobial, antiviral, hepatoprotective, neuroprotective, and immunomodulatory effects; however, Radix Bupleuri could also lead to hepatotoxicity, particularly in high doses and with long-term use. Concerns exist regarding hepatotoxicity due to saikosaponins and the essential oil of bupleurum root, particularly at high doses. The main adverse effect associated with bupleurum root is liver damage, particularly with high doses, which indicates that an established maximum tolerated dose is critical for clinical use of bupleurum root extract and purified compounds.

Modern studies have shown that Bupleuri Radix caused acute liver injury, hepatocyte apoptosis, and acute hepatitis following overdose or long-term, unrestricted, and unjustified use. There have been a few case reports of liver damage with excess doses of bupleurum.

Alcohol extractions of Bupleurum have shown greater hepatotoxicity than water extracts; possible liver injury in humans has been reported from B. chinense with anecdotal reports of inducing fibrosis, even though research has shown the plant to prevent liver fibrosis.

Reported Serious Adverse Events

There were reports of renal and liver injury associated with the use of an injectable Bupleurum preparation in Japan in the 1980s that combined the herb with interferon and other compounds; the adverse effects were proposed to be the result of hypersensitivity reactions and included two cases of hypokalemia and renal failure associated with the use of an intravenous preparation, one of which was fatal via hypersensitivity shock.

Sho-saiko-to treatment is contraindicated with interferon drug therapy because there is an increased risk of pneumonitis; Sho-saiko-to has also been reported to cause acute hepatitis.

Neurotoxicity Risk and Species Adulteration

Some components in sibling species of Bupleuri Radix, including bupleurotoxin, acetylbupleurotoxin, and saikosaponin D, have been reported to have neurotoxic effects and hepatotoxicity, respectively. There were approximately 36 Bupleurum species and varieties in different districts and markets due to slightly different morphological appearances; B. longiradiatum Turcz. contains toxic ingredients, and this situation may compromise the values of Radix Bupleuri and even imperil the safety of consumers. A published case report noted the discovery of the nephrotoxic adulterant Aristolochia manshuriensis roots in a commercial sample of Chaihu, underscoring the importance of source authentication.

Drug Interactions — Cytochrome P450

Laboratory studies suggest bupleurum extracts may increase the risk of side effects of drugs that are substrates of CYP2C9; clinical relevance has yet to be determined. Animal studies suggest that bupleurum can induce CYP2E1, CYP2D6, and CYP3A4 enzymes, but herb-drug interactions are more likely at higher doses.

CNS Depressant Interaction

Saikosaponins antagonized the stimulatory effects of caffeine and methamphetamine in mice; synergism with CNS depressants is therefore possible.

Pregnancy and Breastfeeding

There is not enough reliable information to know if bupleurum is safe to use when pregnant or breastfeeding; staying on the safe side and avoiding use is recommended.

Interferon Combination Caution

Data suggest caution and close monitoring in patients with hepatitis B who concomitantly use interferon and bupleurum, given documented increases in liver enzymes, necroinflammatory changes, and elevated cytokine levels observed in animal models of this combination.

9. Summary of Evidence Quality

The scientific evidence base for Chinese thoroughwax (Bupleurum chinense) is dominated by preclinical studies — cell-culture and animal models — with a smaller body of human clinical research that applies mainly to multi-herb formulas rather than bupleurum as a single agent. The highest-quality systematic assessment available, a 2019 Cochrane review of Xiao Chai Hu Tang for chronic hepatitis B, rated the certainty of the evidence as very low. Although bupleurum is used along with other herbs in traditional formulas to treat many conditions, studies in humans are largely lacking. Areas such as antiviral, antipyretic, anti-inflammatory, antidepressant, and anticancer activity all require adequately powered, well-controlled human trials before clinical recommendations can be made. The herb's dual profile — potential hepatoprotective activity at moderate doses, hepatotoxic potential at high doses and with long-term use — is a central safety consideration that warrants attention in both research and practice.

References

Health Conditions

Health conditions that Chinese thoroughwax may help support.

No conditions available.

Body Systems

Body systems that Chinese thoroughwax may help support.

No body systems available.