Asarum sieboldii: A Comprehensive Encyclopedic Reference
1. Identity, Taxonomy, and Natural Source
Asarum sieboldii Miq. is the accepted botanical name for a low-growing, shade-loving perennial medicinal plant belonging to the family Aristolochiaceae (the birthwort family), genus Asarum. It is a low-growing, shade-loving perennial belonging to the Aristolochiaceae family, genus Asarum, that grows to a height of approximately 12 cm above the ground and has a short stem.
Asarum sieboldii, a species of wild ginger native to East Asia, has long been recognised as an important herb in Asian traditional medicine. It is widely distributed across China, Korea, and Japan. The genus Asarum encompasses approximately 90 species, but A. sieboldii and its varieties hold a uniquely prominent position in official pharmacopoeias.
Taxonomic Complexity and Recognised Varieties
The drug known commercially and pharmacopoeially as Xixin (Chinese) or Saishin (Japanese) is derived from three closely related taxa. Three major species — A. heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag., A. sieboldii Miq. f. sieboldii, and A. sieboldii Miq. f. seoulense (Nakai) C. Y. Cheng et C. S. Yang — are designated as the official sources of Asari Radix et Rhizoma (ARR) in the Chinese Pharmacopoeia. The crude drug ARR, also commonly known as Xixin (Chinese) and Saishin (Japanese), is the dried roots and rhizomes of these three species.
Key synonyms and names for A. sieboldii var. seoulense in the literature include: Asiasarum sieboldii F. Maekawa; and it is known popularly as Korean wild ginger, Japanese wild ginger, or, in Korea, Seshin. The plant is popularly known as Seshin in the Republic of Korea and has been well known throughout South-East Asia for more than 2,000 years as one of the most versatile medicinal plants with a wide spectrum of biological activity.
Asarum drugs originate from the dry roots and rhizomes of Aristolochiaceae plants, including Asarum heterotropoides var. mandshuricum, A. sieboldii var. seoulense, or A. sieboldii, with rich chemical composition structure types in the roots and rhizomes, including volatile oils, lignans, flavonoids, alkaloids, amides, and more. It is widely believed that the main active components of Asarum plants are volatile oils, including safrole, methyleugenol, and kakuol.
Common Forms and Preparations
In ancient prescriptions containing Asarum, the dosage forms were mainly Zhu San (powder suspended in decoctions), pills, decoctions, and powders; it was widely used as an anodyne and anti-allergic remedy in many countries of Asia, and also as herbal medicine in many parts of Europe.
The medicinal material is obtained by drying the root of Asarum sieboldii, a perennial plant belonging to the Aristolochiaceae family. The root is gathered between spring and summer, washed clean with water, and dried in shade.
Modern preparations include:
- Dried root and rhizome (crude drug): The pharmacopoeial standard form, used in decoctions.
- Decoctions: The traditional and currently preferred preparation, particularly because boiling reduces concentrations of certain toxic volatile constituents (see Safety section).
- Powders: Used historically, though now viewed with additional caution given the higher content of volatile toxicants compared to decoctions.
- Ethanol/methanol extracts: Used in research settings for isolation of active constituents.
- Essential oils: Obtained by steam distillation of the roots and rhizomes; studied extensively in pharmacological research.
- Multi-herb formulas: ARR was often prescribed together with other Chinese medicines, taken by decoctions or powders, for the purpose of dispelling wind and cold, relieving headache and toothache, stuffy nose, nasosinusitis, rheumatic arthralgia, and phlegm and asthma cough.
2. Traditional and Historical Use
China
Herba Asari and Asiasari Radix (AR) have a centuries-old history as a folk medicine in China, Korea, and Japan. AR has long been used in combination with other herbs to treat cough, toothache, headache, neuralgia, aphthous stomatitis, and gingivitis. AR has long been used in combination with other herbs to treat cough, toothache, headache, neuralgia, aphthous stomatitis, gingivitis, chronic bronchitis, asthma, and allergies.
Asarum was widely utilised in the Shanghan Lun (Treatise on Cold Damage Diseases), the earliest existing formula guide of the Chinese tradition, and it occurs in many traditional formulas that have been passed down.
The Compendium of Materia Medica (Bencao Gangmu), authored by Li Shizhen during the Ming dynasty, included explicit warnings about the herb's dose-dependent toxicity. The famous Chinese medicinal classic work, the Compendium of Materia Medica, states that "Asarum cannot use more than 5 g for a single powder, or people will be suffocated to death," and up until the Qing Dynasty, there are other records stating that "if it can be used in the proper combination with other herbs, its usage limitation will not be so obvious."
Within Traditional Chinese Medicine (TCM) theory, the theory of TCM believes that ARR has the effect of dispelling wind and removing dampness, unblocking the stuffy orifice and relieving pain, and warming the lung to reduce watery phlegm.
Korea
The radix of Asarum sieboldii Miq. has been used to treat pain and inflammation in Korea. It is known in Korean medicine as Seshin and was employed within the broader East Asian classical medicine framework, sharing many uses with the Chinese tradition.
Japan
In Japanese traditional medicine (Kampo), the herb is known as Saishin. The crude drug ARR is also commonly known as Saishin (Japanese) and is widely used as herbal medicine based on the theory of TCM treatment in China, Japan, Korea, Europe, North America, and other countries or regions with a very long history.
Traditional Indications and Preparations
In traditional medicine, the roots of A. sieboldii are used as treatment for all types of colds, fever, chills, headaches, acute toothaches, sinusitis, cough, and dyspnoea due to retention of phlegm, pharyngitis, chronic gastritis, and rheumatoid arthritis.
The herb was historically characterised in TCM as pungent and warm in nature, and was rarely administered alone. ARR is considered to be slightly toxic according to its medication experience, so it is customarily not used alone. Classical compound formulas incorporating Xixin include the well-known Mahuang Fuzi Xixin Decoction (also romanised as Mahuang-Fuzi-Xixin Tang), used classically for conditions presenting with simultaneous exterior wind-cold and interior yang deficiency, and Mahuang Tang (Ephedra Decoction). The Mahuang Fuzi Xixin decoction (MFXD) is widely used to treat allergic rhinitis in China.
3. Key Constituents and Active Compounds
Research has identified a large and chemically diverse range of compounds in A. sieboldii roots and rhizomes. More than 277 chemical ingredients have been discovered. Among them, lignans and volatile oils were found to be the principal sources of active ingredients with a great deal of content in crude drugs and became the indicating ingredients of the quality control of ARR in the Chinese Pharmacopoeia.
Volatile Oils (Essential Oils)
It is widely believed that the main active components of Asarum plants are volatile oils, including safrole, methyleugenol, kakuol, and others. Detailed analysis has further identified additional volatile constituents.
- Methyleugenol: One of the most abundant volatile oil components; also one of the primary toxicological concerns (see Safety section). Analyses showed that the content of methyleugenol in dried herbal drugs ranged from 1.94–16.04 mg/g.
- Safrole: A phenylpropanoid constituent present as a major volatile oil component. The content of safrole in dried herbal drugs tested ranged from 0.14–2.78 mg/g.
- 3,4,5-Trimethoxytoluene (also called 3,5-dimethoxytoluene): The plant contains several chemical constituents, including methyleugenol, 3,4,5-trimethoxytoluene, and safrole, which contribute to its medicinal benefits.
- Myristicin: A phenylpropanoid; comparative studies have found that A. sieboldii has a higher myristicin content than A. heterotropoides.
- Eucarvone and other terpenes: Among the six major essential oil components, eucarvone, 3,5-dimethoxytoluene, and methyleugenol were higher in A. heterotropoides than in A. sieboldii.
Lignans
Lignans are major non-volatile active constituents and key quality-control markers. Notable examples include:
- (−)-Asarinin: A tetrahydrofurofurano-type lignan. Research has shown significant cytotoxic activity in human cancer cell lines (see Anticancer section below).
- (−)-Sesamin: Another lignan documented from this species.
- Asarinin (also known as episesamin): An important indicator constituent for quality control of ARR per the Chinese Pharmacopoeia. When the ratio of characteristic peaks of sarisan to kakuol was greater than 5, the material was identified as A. sieboldii; when the ratio was less than 2, it was identified as A. heterotropoides.
Isobutylamides (Alkamides)
NMR-guided chemical investigation of A. sieboldii var. seoulense yielded twenty secondary metabolites belonging to isobutylamides, lignans, and phenolics. Researchers have focused attention on studying asarinin and essential oils as the indicating ingredients of ARR, but paid less attention to another characteristic component, alkamides, and the role of alkamides in the major efficacy of ARR medication remains to be elucidated.
Phenanthrene Derivatives
Fourteen compounds were isolated from the 95% ethanol reflux extract of Asarum sieboldii Miq. var. seoulense Nakai, including five phenanthrene derivatives, three isobutyl amides, three phenylpropanoids, and three lignins.
Kakuol
Kakuol is a propiophenone derivative specific to the rhizome of Asarum sieboldii and is used as a chromatographic marker for species differentiation. Research has confirmed antifungal activity for this compound (see Antimicrobial section below).
Additional Constituents
Various toxins were found in different parts of the Asarum plant, including major toxins such as aristolochic acids, safrole, terpinolene, methyleugenol, sarisan, 3,5-dimethoxy nutmeg, and other minor toxins including lignans, ketones, vinyl compounds, benzene derivatives, and phenanthrene derivatives.
Previous phytochemical investigations on the roots of A. sieboldii resulted in the isolation of essential oils, alkamides, lignans, and alkaloids.
4. Established and Proposed Mechanisms of Action
Analgesia and Antinociception
Preclinical evidence (animal models) has provided insight into analgesic mechanisms. Administration of methanol extract of Asarum radix caused dramatic anti-nociceptive effects based on acetic acid writhing and tail-flick assays. When naloxone was pre-treated, the extract failed to exert such anti-nociceptive effect in the tail-flick assays, suggesting that the extract has opioid-like activity.
The extract caused inhibition in the bradykinin/histamine-mediated ileum contractions of guinea pig. Together, these results provide evidence that the methanol extract of Asarum radix exerts anti-nociceptive and anti-inflammatory effects by activating opioid receptors as well as by inhibiting bradykinin- and histamine-mediated actions.
Anti-inflammatory Mechanisms
Asarum extract was found to significantly reduce the severity of arthritis by decreasing hind paw swelling, the arthritis index, the spleen index, and TNF-α, IL-1β, and IL-6 expression levels in plasma. In vitro, Asarum extract inhibited the nuclear factor NF-κB and mitogen-activated protein kinase (MAPK) signalling pathways.
Network pharmacological analysis of ARR constituents has proposed further anti-inflammatory targets. Analysis of 119 constituents of Asari Radix et Rhizoma suggested that the anti-inflammatory effect might be related to COX-2, COX-1, iNOS, MAPK14, NR3C1, PPARG, and TNF.
Local Anesthesia
The numbing, pungent quality of the root — noted historically and described as making the tongue numb — has a biochemical basis. Several volatile components and alkamides are thought to interact with ion channels and nociceptors, contributing to local anesthetic effects that underpin the herb's traditional use in toothache and oral pain.
Respiratory and Antitussive Effects
Modern pharmacological studies have shown that Asarum species exhibit anti-inflammatory, antitussive, anti-allergic, anti-hyperlipidaemic, and anti-myocardial ischaemia properties by enhancing myocardial contractility, antiarrhythmic activities, and other mechanisms. Multiple studies have documented that Asarum essential oil exhibits a significant anti-inflammatory effect both in vivo and in vitro, which indicates that it is helpful for relieving cough and asthma, relieving bronchospasm, and reducing inflammation in the lungs.
Neurological Mechanisms
Sarisan can lead to carcinogenesis through liver metabolism and to respiratory disorders by inhibiting nerve transfer in medullary neural networks. Separately, neuroprotective effects have been attributed to certain lignans and phenolic constituents.
5. Scientific Evidence by Area of Use
5.1 Pain and Analgesia
Evidence level: Preclinical (animal and in vitro); no human clinical trials specifically on A. sieboldii monotherapy identified.
The analgesic effects of Asarum radix have been studied in animal models. As noted above, methanol extracts produced robust anti-nociceptive effects in rodent acetic acid writhing and tail-flick tests, with these effects partially reversed by the opioid antagonist naloxone, implicating opioid receptor involvement. Additional mechanisms include inhibition of bradykinin- and histamine-mediated smooth muscle contractions in guinea pig ileum preparations, and inhibition of prostaglandin pathways via COX enzymes. Essential oil and ethanol extract showed a dose-dependent reduction in the degree of swelling and an increase in the inhibition rate on acetic acid writhing in mice; Asarum essential oil proved to be more effective than ethanol extract in the pharmacodynamic study.
Studies on alkamides — a constituent class that had historically received less attention — have begun to characterise their contribution to antinociception. For a long time, researchers focused attention on studying asarinin and essential oils, the indicating ingredients of ARR, but paid less attention to another characteristic component, alkamides, and the role of alkamides in the major efficacy of ARR medication remains to be elucidated.
No rigorous, controlled clinical trials on A. sieboldii alone for pain endpoints in humans have been identified in the peer-reviewed literature. Evidence remains preclinical.
5.2 Anti-inflammatory Activity
Evidence level: Preclinical (animal and cell culture); limited clinical data for combination formulas only.
A published animal study using a Freund's complete adjuvant-induced arthritis model in rats evaluated Asarum extract. The aim of the study was to investigate the protective effect of Asarum extract on rats with adjuvant arthritis and to determine the underlying mechanism. An adjuvant arthritis model was established by injecting Freund's complete adjuvant into the rats, and the degree of toe swelling, arthritis index, spleen index, and the expression levels of TNF-α, IL-1β, and IL-6 were measured. The extract demonstrated significant anti-arthritic effects. Inhibition of NF-κB and MAPK pathways was confirmed in macrophage cell lines.
In modern pharmacological studies, in vivo and in vitro research showed that ARR has multiple pharmacological activities, including antinociceptive, anti-inflammatory, neuroprotective, anti-depressive, anti-ischaemic, antithrombotic, antitussive, suppression of immune rejection, anti-allergic, antitumor, and antimicrobial activities. However, all of these activities in the context of A. sieboldii specifically are supported predominantly by preclinical data.
5.3 Respiratory Conditions (Cough, Asthma, Allergic Rhinitis)
Evidence level: Preclinical and limited combination-formula clinical evidence; no standalone human trials for A. sieboldii.
Ginger and Asarum application by acupoint sticking therapy have been suggested to improve the clinical symptoms of bronchial asthma. This represents an area where limited clinical application data exist, but these concern combination treatments using acupoint sticking (a form of topical application), not oral monotherapy with A. sieboldii.
The well-known classical formula Mahuang Fuzi Xixin Decoction (containing Xixin as one of three herbs alongside Ephedra and prepared Aconite) has received more targeted study. The Mahuang Fuzi Xixin decoction is widely used to treat allergic rhinitis in China; however, its active compounds and therapeutic mechanisms are not fully clarified. Mechanistic studies using LC-MS/MS and network pharmacology have been conducted, but rigorous randomised controlled trials isolating the contribution of A. sieboldii are lacking.
5.4 Antimicrobial and Antifungal Activity
Evidence level: In vitro only.
The plant is renowned for its anti-inflammatory, analgesic, antimicrobial, antifungal, and antioxidant properties. Specific research has identified the propiophenone derivative kakuol, isolated from the rhizome, as having antifungal activity. Additional in vitro studies have found antibacterial activity. Research has revealed plant species with potent antimicrobial properties effective primarily against gram-positive organisms, including Staphylococcus aureus and S. epidermidis.
Antifungal activity has also been demonstrated for essential oil fractions in cell-based assays. No human clinical trials evaluating A. sieboldii for infectious conditions have been identified. All antimicrobial evidence is currently limited to in vitro experiments.
5.5 Oral Health and Dentistry
Evidence level: Preclinical and in vitro; no controlled human dental trials identified.
Whereas literature search highlights the potential application of A. sieboldii in herbal medicine, to date its application in dentistry remains largely unexplored, with the existing literature vastly fragmented in various sources. Its ability to inhibit nitric oxide release, along with its neuroprotective effects, further enhances its potential for relieving pain and inflammation. With these therapeutic benefits, A. sieboldii presents a promising natural alternative or complementary option to conventional dental treatments capable of addressing a wide range of oral health conditions. This assessment, however, is based on the aggregation of in vitro and animal data rather than clinical trials.
5.6 Anticancer / Cytotoxic Activity
Evidence level: In vitro and early preclinical; no human clinical trials.
A PMC-published study investigated the cytotoxic potential of compounds isolated from A. sieboldii roots against human ovarian cancer cell lines. The isolates were evaluated for their cytotoxicity against human ovarian cancer cells (A2780 and SKOV3) using an MTT assay. Of the isolates, (−)-asarinin (1) exhibited the most potent cytotoxicity to both A2780 and SKOV3 cells. A propidium iodide/annexin V-FITC double staining assay showed that (−)-asarinin induces apoptotic cell death in ovarian cancer cells.
The findings show that (−)-asarinin from the roots of A. sieboldii may induce caspase-dependent apoptotic cell death in human cancer cells. Additionally, a 70% EtOH extract from Asiasari radix induced apoptosis preceded by a tight cell cycle arrest in the G2/M phase, suggesting that the extract prevented the growth of HCT-116 human colon cancer cells. All anticancer findings are in vitro and no translation to human trials has been established.
5.7 Neuroprotective and Neurological Effects
Evidence level: In vitro and early preclinical; traditional-use-supported hypothesis.
The plant has been used for centuries as an ingredient in a well-known Traditional Chinese medicine, "Xixin," to treat symptoms of the neurodegenerative condition Parkinson's Disease. Compounds from A. sieboldii var. seoulense were evaluated against an olfactory cell line derived from a Parkinson's Disease patient using a phenotypic assay. Several isolates were found to induce moderate perturbation to the staining of mitochondria, autophagosome, and α-tubulin of the cells. Considering that PD pathogenesis is closely related to these cellular compartments, the results provided a rationale for the traditional application of Xixin in the treatment of PD. These findings are preliminary, limited to a cell-based assay, and require further investigation.
In vitro research showed ARR has multiple pharmacological activities, including neuroprotective and anti-depressive activities. However, the mechanistic basis and clinical relevance of these neuroprotective effects require substantially more research to validate.
5.8 Cardiovascular Effects
Evidence level: Preclinical; no human trials specifically for A. sieboldii.
Modern pharmacological studies have shown that Asarum species exhibit anti-hyperlipidaemic and anti-myocardial ischaemia properties by enhancing myocardial contractility and antiarrhythmic activities. These effects have been characterised in animal studies. In vitro and in vivo research showed that ARR has pharmacological activities including anti-ischaemic and antithrombotic effects. No human cardiovascular clinical trials for A. sieboldii have been identified.
6. Body Systems Associated with Asarum sieboldii
- Nervous system: Analgesic, local anaesthetic, and proposed neuroprotective effects; traditional use for headache, neuralgia, and toothache.
- Respiratory system: Antitussive, anti-asthmatic, and expectorant uses; traditional application for cough, asthma, sinusitis, and allergic rhinitis.
- Musculoskeletal system: Anti-arthritic and anti-inflammatory applications, including traditional use for rheumatic arthralgia.
- Immune system: Anti-allergic and immunomodulatory (including immunosuppressive) effects documented preclinically.
- Cardiovascular system: Antiarrhythmic, antithrombotic, and cardioprotective effects documented preclinically.
- Oral / dental: Historically prominent use for toothache, gingivitis, and aphthous stomatitis; antimicrobial properties relevant to oral pathogens.
- Oncological (preclinical only): Cytotoxic and pro-apoptotic effects on cancer cell lines in vitro.
- Renal / hepatic (safety concern): Certain constituents are associated with nephrotoxic and hepatotoxic risk, representing a safety dimension rather than a therapeutic target.
7. Dosage Forms and Reported Dosages
The recommended daily dosage according to the Chinese Pharmacopoeia 2020 is not more than 3 g.
The China Pharmacopoeia (2015 edition) recommends the dosage of Asarum that should be used is 1–3 g and suggests that the risk of nephrotoxicity should be noted.
In the Advanced Textbook of Traditional Chinese Medicine and Pharmacology, where asarum is classified with herbs to warm the interior rather than with herbs to relieve the surface, it is stated that "large doses should be avoided." The dosage range indicated is 1–3 grams, which, compared to many Chinese herbs, is already quite low.
Decoction processing substantially reduces the content of toxic volatile constituents. A study examining this effect found that boiling significantly reduced safrole and methyleugenol levels in the final preparation, which is cited as a pharmacological and safety rationale for preferring the decoction form over raw powder. Many species of Asarum contain safrole and methyleugenol as the main components of their volatile oils; toxicological studies have shown that safrole and methyleugenol may be hepatocarcinogens and/or genotoxic agents, leading to concerns regarding habitual consumption of this herbal drug.
For research experiments, decoctions were prepared by soaking the herb in 10 times the volume of water for 30 minutes, then boiling for half an hour, filtering with gauze, and repeating the extraction once more with the residue.
8. Safety Considerations and Interactions
Toxic Constituents — Overview
The usage of asarum is generally not recommended without caution due to its toxicity. Previous studies have detected a number of potentially toxic components in asarum, including safrole, methyleugenol, aristolochic acids, asarone, 3,5-dimethoxytoluene, and benzene derivatives. These components are associated with toxicity in multiple organs, including the central nervous system, kidneys, and liver.
Aristolochic Acids (AAs) and Nephrotoxicity
Like the related genus Aristolochia, Asarum species contain aristolochic acids and aristolactams. These nitrophenanthrene derivatives have nephrotoxic and carcinogenic effects.
A critical pharmacopoeial revision occurred as a direct result of this concern. Before 2005, the whole Asarum herb was recorded as the medicine in the Chinese Pharmacopoeia. The overground part of the Asarum plant contains AA-I, which has been proven to cause aristolochic acid nephropathy. However, AA-I content is very low in the underground part (roots on the rhizome) of Asarum. Therefore, the revised Chinese Pharmacopoeia in 2005 recommended only the root and rhizome as the medicinal part of Asarum.
The flower of Asarum sieboldii contains a relatively high amount of aristolochic acid, which may induce nephrotoxicity.
A long-term study on the closely related species A. heterotropoides decoction concluded: Consumption of Asarum heterotropoides F. Schmidt (Xixin) with controlled doses and periods is relatively safe as the contents of AA analogues in Xixin and its formulations were far below those causing acute toxicity; but the long-term toxicity of Xixin still needs further study.
The clinical safety record, while imperfect, provides context: Asarum also contains aristolochic acids; however, from the literature evaluation, there have been only eight cases of Asarum-related aristolochic acid toxicity reported over approximately 45 years, which relates to overdose of the herbs. Preclinical chemical study evaluation also concluded that the amount of aristolochic acid in the patent form of the herbs was negligible, and the decoction of the root part of Asarum is recommended for use, which agrees with TCM usage.
Safrole and Methyleugenol — Hepatotoxicity and Genotoxicity
Safrole has been revealed to be associated with the pathogenesis of hepatocellular carcinoma and to lead to respiratory paralysis. Safrole may inhibit cytochrome P450 enzymes and result in the production of reactive metabolites, leading to the inhibition of enzyme activity and increasing the risk of hepatocellular carcinoma progression.
Toxicological studies have shown that both safrole and methyleugenol may act as hepatocarcinogens and/or genotoxic agents, raising concerns about the potential risks associated with regular consumption of this herbal remedy.
Asarone — Cytotoxicity and Genotoxicity
α-Asarone exhibits higher cytotoxicity due to its enhanced metabolism. β-Asarone is also cytotoxic, albeit less so than α-asarone. β-Asarone, due to its increased metabolism and epoxide formation, exhibits genotoxicity.
Respiratory and CNS Toxicity
Adverse events associated with Asarum include hepatotoxicity, nephrotoxicity, and neurologic reactions. According to clinical reports, Asarum essential oil could cause respiratory excitation at low doses and respiratory depression at high doses. Because of the two-way modulation of the nervous system by Asarum essential oil, it is vital to find the threshold between the therapeutic effect and toxicity and determine a safe therapeutic window.
Dose-Dependent Toxicity and Overdose
The main problem with use of asarum, as understood by Chinese herbalists, is related to overdosing. Classical Chinese pharmacopoeial sources warn explicitly against high doses, particularly when the drug is given as a powder. The decoction form is considered safer, as boiling volatilises and degrades both safrole and methyleugenol, reducing concentrations in the final preparation.
Herb-Drug Interactions (Traditional Sources)
Some traditional sources suggest this herb may antagonise Fructus Corni Officinalis (Shan Zhu Yu) and Radix Astragali Membranacei (Huang Qi) and counteract Talcum (Hua Shi). These potential interactions are derived from traditional texts; pharmacokinetic or mechanistic data from controlled studies are not available for these specific pairings.
Given that safrole inhibits cytochrome P450 enzymes, there is a theoretical basis for interactions with drugs that are substrates of these enzymes, though this has not been systematically studied in clinical populations.
Precautions Regarding Plant Part and Sourcing
Three species — A. heterotropoides Fr. Schmidt var. mandshuricum, A. sieboldii Miq. var. seoulense Nakai, and A. sieboldii Miq. — are recognised as original "Asiasari Radix et Rhizoma." These species do not contain aristolochic acids (the nephrotoxins present in other Asarum species) and therefore the roots of AR are recommended for use.
In the normal practice of traditional Chinese medicine, about a dozen species of Asarum are used as sources of Xixin, making the presence of aristolochic acid in some of the raw materials, and the formulas produced with them, a possibility. Also, as detection methods improve, minute amounts of aristolochic acid might be found in most, or even all, Asarum species.
The majority of Asarum samples studied contained potentially nephrotoxic aristolochic acid analogues, including 9-methoxy aristolactam IV, aristolactam I, and aristolactam IV. These compounds were present in methanol as well as water extracts, and were detected in all parts of the plant.
References
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