Bupleurum
Scientific Name(s): Bupleurum falcatum L.
Common Name(s): Beichaihu, Bupleuri Radix, Bupleurum root, Chai-hu, Chaihu, Hare's ear root, Radix Bupleuri, Saiko (Japanese), Thorow wax, Thorowax
Medically reviewed by Drugs.com. Last updated on Nov 21, 2024.
Clinical Overview
Use
Bupleurum has traditionally been used for various purposes, including analgesic, antipyretic, immunomodulatory, anti-inflammatory, and hepatoprotective effects; however, clinical trial data are lacking to recommend use for any indication.
Dosing
Clinical trial data are lacking to support specific dosing recommendations.
Contraindications
Contraindications have not been identified.
Pregnancy/Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
None well documented.
Adverse Reactions
Mild lassitude, sedation, and drowsiness have been reported. Large doses may increase flatulence and bowel movements. Allergy to injected bupleurum has been reported.
Toxicology
No data.
Scientific Family
- Apiaceae (carrot)
- Umbelliferae (carrot)
Botany
Bupleurum is a perennial herb that grows primarily in China but is also cultivated in other areas. Bupleurum grows to approximately 1 m in height and requires abundant sun to flourish. The leaves are long and sickle-shaped with parallel veining. Terminal clusters of small, yellow flowers appear in autumn. The long cone or column-shaped, single or branched root is 10 to 20 cm in length and 0.5 to 1.5 cm in diameter; the root is light brown to brown, may be wrinkled, and is easily broken.(Chevallier 1996, USDA 2022, WHO 1999) Synonyms of B. falcatum include Bupleurum chinense DC. and Bupleurum scorzonerifolium Willd.
More than 20 species of the genus Bupleurum have been described, including a toxic species, Bupleurum longiradiatum, found in northeast China and Bupleurum kaoi, which is indigenous to Taiwan.(WHO 1999, Yuan 2017) 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.(Tian 2009) Confusion exists regarding the species B. scorzonerifolium Willd., which may be the same as B. falcatum L. var scorzonerifolium.(Ashour 2011, WHO 1999)
History
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. It forms an integral part of many Kampo medicines (the Japanese adaptation of traditional Chinese medicine), including shosaikoto, daisaikoto, saikokeishito, hochuekkito, saibokuto, and saireito.(Ikegami 2006, Tian 2009) Bupleurum has been used as a liver tonic, with spleen and stomach toning properties. Bupleurum has also traditionally been used to promote perspiration and treat fever associated with influenza, the common cold, malaria, and pneumonia; flu; distending pain in the chest; and menstrual disorders.(Ikegami 2006, Tian 2009, WHO 1999)
Chemistry
The main chemical constituents identified include saponins, coumarins, polysaccharides, fatty acids, flavonoids, lignans, polyacetylenes, and steroids.(Ashour 2011, USDA 1992, WHO 1999, Yuan 2017)
Bupleurum contains triterpene saponins or saikosides, also known as saikosaponins. Levels of saikosaponins vary widely between species (ie, B. falcatum 2% to 8% and B. chinense 1.7%) and between wild and cultivated species. Levels also depend upon growing conditions.(Tian 2009) Root parts of bupleurum have been analyzed, resulting in the discovery of many saikosaponins. Saponins, along with flavonoid compounds and indole alkaloid glucosides, have been found in the aerial parts of some species. Saikogenins A, B, C, and D are also present in the plant. Spinasterol, stigmasterol, and rutin have been found, as well as pectin-like polysaccharides (bupleurans).(Ashour 2011) The essential oil contains various chemical compounds such as Li05b and long-chain unsaturated fatty acids.(Li 2005)
Uses and Pharmacology
Analgesic uses
Animal data
In vivo animal experiments suggest bupleurum extracts and sapogenin A possesses analgesic effects.(WHO 1999) In male mice, essential oil from B. falcatum roots demonstrated both anti-allodynic and antinociceptive effects. Data suggest antinociceptive activity may be due to activation of the L-arginine–NO–cGMP-KATP channel pathway as well as interaction of opioid, peroxisome proliferator-activated, and cannabinoid receptors.(Ahmadimoghaddam 2021)
Anti-addictive/Anorectic effects
Animal data
B. falcatum extracts may be a valuable source of pharmacological agents with anti-addictive and anorectic potential. The suppressing effect of a saikosaponin-enriched extract of B. falcatum on alcohol and chocolate self-administration in rats has been recorded.(Maccioni 2022)
Antidepressant effects
Animal data
In rats, B. chinense upregulated PRKACA and CREB expression and level of cAMP, the key metabolite in the cAMP/PKA/CREB pathway, while reducing the inflammatory response to depression treatment. These findings support future research on the potential antidepressant effects of B. chinense.(Chang 2022)
Antipyretic effects
Animal data
Oral decoctions of bupleurum, subcutaneous injection of the root extract, and oral saikosaponins have shown antipyretic effects in rats and rabbits.(WHO 1999) Nasal gel and nasal spray made from the essential oil of bupleurum reduced fever in rats and rabbits in a dose-dependent manner.(Cao 2007, Xie 2006)
Antiviral effects
In vitro data
In in vitro studies, bupleurum inactivated enveloped viruses, including measles and herpes, but had no effect on nonenveloped viruses (eg, polio).(Ushio 1992) Saikosaponins inhibited coxsackie B virus,(Cheng 2007) and saikosaponin B inhibited the human coronavirus, which is responsible for severe acute respiratory syndrome.(Cheng 2006) In vitro experiments have also shown that saikosaponin D suppresses enterovirus A71 infection by inhibiting autophagy.(Li 2019)
Asthma
Animal data
Saikosaponin A reduced antigen challenge–induced bronchoconstriction in experiments conducted on guinea pigs.(Park 2002)
Cancer
Animal and in vitro data
Limited animal experiments have been conducted. In studies in mice with lung adenocarcinoma, a dose-dependent antiproliferative effect on tumor growth was observed with B. scorzonerifolium extracts.(Chen 2006, Cheng 2005) Extracts from the roots of B. longiradiatum were antiangiogenic in vitro but were not effective against lung tumors in mice and were fatally toxic at higher dosages.(You 2002)
In in vitro experiments, bupleurum demonstrated cytotoxic effects on several human cell lines, including lung adenocarcinoma as well as breast, colon, hepatocellular, and ovarian cancers.(Cheng 2005, Hsu 2004, Kang 2008, Law 2014)
The saponin fraction of B. kaoi, the acetone extract of the roots of B. scorzonerifolium, a polysaccharide bupleuran from the roots of B. falcatum, a novel lignin (isochaihulactone), and the extract from the root of B. longiradiatum have all been evaluated for antiproliferative and apoptotic effects.(Cheng 2003, Cheng 2005, Cheng 2006, Hsu 2004, Kang 2008, Ohtsu 1997, You 2002)
In vitro experiments have also shown that total bupleurum saponin extracts can inhibit proliferation and induce apoptosis of colon cancer cells by regulating the PI3K/Akt/mTOR pathway.(Zhang 2022)
Gastric ulcer
Animal and in vitro data
In in vivo animal experiments, the polysaccharide bupleurans and saikosaponins reduced effects of induced gastric ulcers, increased healing rates, and were comparable with sucralfate. Suggested mechanisms of action include reinforcement of the gastric mucosal barrier and an antisecretory action on acid and pepsin.(Amagaya 1998, Hung 1993, Matsumoto 2002, WHO 1999) An ethanol extract of the aerial parts of the plant showed anti–Helicobacter pylori effects in vitro.(Li 2005)
Hepatoprotective effects
Animal and experimental data
Saikosaponins and root and leaf extracts have demonstrated protective effects on acetaminophen- and carbon tetrachloride–induced hepatic injury in rats. The majority of experiments showed positive effects on ALT and AST as well as histological changes (eg, cell membrane malfunctions, cell death), with effects attributed mainly to decreased oxidative stress.(Chiu 1988, Lin 1990a, Lin 1990b, Liu 2006, Wang 2004, WHO 1999, Wu 2008, Yen 1991)
Immunomodulatory/Anti-inflammatory effects
In vitro and animal data
In in vitro studies, root extracts, polysaccharide bupleurans, and individual saikosaponins (especially saikosaponin D) have demonstrated effects on the immune system (ie, upregulation, downregulation). Increased antibody response, induction of type 1 interferons, and upregulation of macrophages have been demonstrated.(Cheng 2007, Matsumoto 2003, Sun 2006, WHO 1999, Wong 2009) Bidirectional effects on T lymphocytes have also been demonstrated, possibly a dose-dependent effect.(Chang 2003, Leung 2005, Sun 2006, Sun 2009, WHO 1999, Wong 2009) Anticomplementary effects by polysaccharide extracts of Bupleurum smithii roots(Xu 2007) and inhibition of cyclooxygenase and lipoxygenase by aerial parts of the related species Bupleurum fruticescens have also been demonstrated.(Prieto 2004)
In vivo rat paw edema experiments have been conducted using crude extracts of B. falcatum, purified saponins 3 and 7, and some saikosaponins A and D. The anti-inflammatory effect was similar to that of prednisolone(WHO 1999) but not of dexamethasone.(Navarro 2001) Saikosaponin C prevented nephritis in mice treated with nephrotoxic serum but did not prevent the formation or deposition of immune complex, suggesting an upregulation of enzymes or mechanisms that digest and clear the immune complexes.(Chen 2008) A review of the anti-inflammatory mechanisms and studies has been published.(Yuan 2017)
Memory impairment
Animal data
In an Alzheimer's disease mouse model, administration of saikogenin F isolated from B. smithii significantly mitigated learning and cognitive impairment as well as neuroimflammation compared to controls.(Chen 2022)
Osteoporosis
Animal data
In rat experiments, high doses of B. falcatum partially prevented estrogen deficiency–induced bone loss via anti-osteoclastogenic activity, potentially due to enhanced iNOS/NO signaling.(Yeom 2018)
Vasorelaxant effects
Animal data
Chloroform extracts from the roots of the related species Bupleurum fruticosum exerted vasorelaxant effects on rat aorta.(Testai 2005)
Dosing
Clinical trial data are lacking to support specific dosing recommendations.
Pregnancy / Lactation
Avoid use. Information regarding safety and efficacy in pregnancy and lactation is lacking.
Interactions
Antiaggregating effects on platelets by the lactone bupleurumin (extracted from the aerial parts of B. falcatum) have been demonstrated in vitro.(Kim 2007) Therefore, potentiation of thrombolytic and antiaggregating medicines is theoretically possible. Saikosaponins antagonized the stimulatory effects of caffeine and methamphetamine in mice; synergism with CNS depressants is possible.(Chang 1987, WHO 1999) Inhibition of CYP3A4 by aqueous extracts has also been demonstrated.(Ashour 2017)
Bupleurum forms an integral part of many Kampo medicines (eg, shosaikoto, daisaikoto, saikokeishito, hochuekkito, saibokuto, saireito) for which interactions have been reported. Preparations include combinations of bupleurum with glycyrrhiza, scutellaria root, ginseng, jujube fruit, astragalus root, magnolia bark, alisma rhizome, and rhubarb.(Ikegami 2006) Assigning causality in reported drug interactions to individual plant components is difficult.
Adverse Reactions
Bupleurum has produced mild lassitude, sedation, and drowsiness in some individuals.(WHO 1999) Large doses have been reported to increase flatulence and bowel movements.(WHO 1999) Allergy to injected bupleurum has been reported.(Chang 1987)
Bupleurum root is an integral part of many combination preparations for which adverse reactions have been reported. In the case of reported drug interactions or adverse effects, assigning causality to individual plant components is difficult.(Aiba 2007) Adult respiratory distress syndrome has been reported, with at least 1 case attributed to bupleurum.(Shiota 1996)
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.(Yuan 2017)
Toxicology
Limited pharmacokinetic information is available in humans. Crude saikosaponins show low-medium toxicity in mice (oral median lethal dose of 4.7 g/kg and intramuscular median lethal dose of 112 mg/kg).(Sun 2009) Methanolic extracts of B. falcatum have not shown mutagenic effects in most modified Ames Salmonella tests; however, one report found enhanced mutagenic activity with a hot-water extract of B. falcatum.(WHO 1999) Concerns exist regarding hepatotoxicity due to saikosaponins and the essential oil of bupleurum root, particularly at high doses.(Yuan 2017)
Index Terms
- Bupleurum chinense DC.
- Bupleurum fruticescens
- Bupleurum fruticosum
- Bupleurum longiradiatum
- Bupleurum scorzonerifolium Willd.
- Bupleurum smithii
- Bei Chaihu
- Bupleurum kaoi
- Chaihu
- Nan Chaihu
- Umbelliferae
References
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