Calamus

Other Names

Acore aromatiqueAcore calameAcore odorantAcore roseauAcore vraiAcoro aromaticoAcoro verdaderoAcorus americanusAcorus angustatusAcorus angustifoliusAcorus aromaticusAcorus belangeriAcorus calamusAcorus calamus L.Acorus calamus subsp. vulgarisAcorus calamus var. americanusAcorus calamus var. angustatusAcorus calamus var. angustifoliusAcorus calamus var. belangeriAcorus calamus var. calamusAcorus calamus var. europeusAcorus calamus var. vulgarisAcorus calamus-aromaticusAcorus casiaAcorus commersoniiAcorus europaeusAcorus flexuosusAcorus floridanusAcorus odoratusAcorus terrestrisAcorus undulatusAcorus verusAcorus vulgarisAjil-i-turkiAkoronAksir-i-turkiAsian sweet flagBachBachaBajBajaiBajeBeewortBelle-AngéliqueBhadraBhutanashiniBitter pepper rootBitterrootBodhaniyaBojhoCalamoCálamoCalamo aromaticoCálamo aromáticoCalamus aromaticusCalamus rootCanna odoriferaCh'angCh'ang-p'uChang puCinnamon sedgeEurasian sweet flagFlag rootGalaniGhorabachGhorbachGladdonGolomiGora-bachGorbachGrass myrtleGrass-leaf sweetflagHaimdvatiIkshuparniJatilaJerangauJunco-de-cobraKalmoesKalmoeswortelKalmusKangaKshudrapatriLomashaLubiganMangalyaMashaMeethibachMuskrat rootMusquashMyrtle flagMyrtle grassMyrtle rootMyrtle sedgeNi chang puPine rootRakshoghniRat rootRoseau odorantSadgranthaSafed bachSchleshmaghniSea sedgeShadagranthaShadgranthaShataparvikaShi chang puShoubuSmaraniSwaySweet calamusSweet caneSweet cinnamonSweet flagSweet grassSweet myrtleSweet rootSweet rushSweet sedgeTikshnaUgraUgragandhaUgragranthiVachVachaVachhaVadajaVajVasa bachVasambuVashVashambuVashampaVayambhuVayambuVayamburVayampuVekhandVekhandaVijayaWada kahaXiang puYe chang pu

Synopsis

Calamus (Acorus calamus L.): A Comprehensive Reference

1. Identity and Botanical Classification

Scientific name: Acorus calamus L. Family: Acoraceae. Common names: Sweet flag, calamus root, muskrat root, sway. Traditional names: Vacha (Sanskrit, Ayurveda), Shi Chang Pu (Traditional Chinese Medicine), Rat Root (several North American Indigenous traditions), Bach (Unani medicine).

Acorus calamus — also called sweet flag, sway, or muskrat root — is a species of flowering plant containing psychoactive chemicals; it is a tall wetland monocot of the family Acoraceae, in the genus Acorus. Calamus is a semi-evergreen, perennial, hairless herb native to much of Asia and also found throughout North America and Eastern Europe, found in damp, swampy areas. The leaves are bright green and sword-shaped, with wavy margins that thicken in the middle; the plant grows to approximately 2 m in height. The creeping rhizome is pale yellow to pinkish brown on the outside and white to pinkish on the inside.

The genus name Acorus is derived from the Greek words ákoros, meaning a plant with aromatic rhizomes or iris, and kálamos, meaning cane or reed. According to the International Union for Conservation of Nature and Natural Resources, the plant is native to India, China, Japan, Korea, southeastern and central Asia, Mongolia, Russia, and North America.

1.1 Ploidy Varieties and Their Significance

One of the most pharmacologically and toxicologically important features of Acorus calamus is the existence of distinct cytotypes (chromosome-number variants) whose chemical compositions differ markedly.

Acorus calamus L. yields different races depending upon the number of chromosomes in the plant cells and consequently different drug types with varying content of beta-asarone. The phenylpropane derivative beta-asarone proved to be carcinogenic in several animal tests. The diploid drug does not contain traceable amounts of beta-asarone; the triploid variety contains 0.3 per cent in the rhizome; the tetraploid yielded two races with (a) 2 per cent and (b) between 4 and 8 per cent beta-asarone.

There are four different types of calamus; some contain a cancer-causing chemical called beta-asarone. The North American and European varieties contain little to no beta-asarone, but others contain up to 96%. The tetraploid variety used predominantly in Asian traditional medicine — and exported widely — is the variety of greatest toxicological concern.

1.2 Common Forms and Preparations

The primary plant part used medicinally is the dried rhizome. When the rhizome is dried, it loses 70–75 percent of its weight, but drying enhances the aroma. The rhizome can be stored for up to three years before it loses its aromatic oil. Common preparation forms documented in the ethnobotanical and pharmacological literature include:

Crude dried rhizome powder (churna): The most traditional Ayurvedic form, used in fixed-dose powders and capsule preparations.
Decoctions and aqueous infusions: Rhizome pieces boiled or steeped in water, used orally for digestive and neurological complaints.
Hydroalcoholic extracts: Standardized tinctures and extracts used in both traditional and modern research contexts.
Essential oil: The fragrant oil from the rhizome is used as a flavoring agent in alcoholic beverages, fragrances, perfumes, and sacred oils.
Shodhita (purified) rhizome: In Ayurveda, the rhizome is used only after a purification step (shodhana), in which it is boiled in media such as cow's milk. Analytical studies have reported that this processing significantly reduces the rhizome's beta-asarone content, an effect attributed largely to volatilization of the heat-labile compound during prolonged boiling.
Chewed fresh rhizome: Chewing the rhizome has been said to relieve irritated throats and remove the odor of tobacco.

2. Historical and Traditional Use

Acorus calamus (Sweet flag) has a long history of use and has numerous traditional and ethnomedicinal applications. Since ancient times, it has been used in various systems of medicine such as Ayurveda, Unani, Siddha, and Chinese medicine for the treatment of various ailments including nervous disorders, appetite loss, bronchitis, chest pain, colic, cramps, diarrhea, digestive disorders, flatulence, gas, indigestion, rheumatism, cough, fever, inflammation, depression, tumors, hemorrhoids, skin diseases, numbness, general debility, and vascular disorders.

2.1 Ancient and Classical World

Acorus calamus has been used as a hallucinogen since ancient times and has several uses in folk medicine. It may have been one of the constituents of the Holy Oil that God commanded Moses to make (Exodus 30) and is mentioned by ancient writers on medicine, such as Hippocrates, Theophrastus, Dioscorides, and Celsus.

Acorus calamus was discovered in the tomb of Pharaoh Tutankhamen of Egypt. Egyptian records place calamus among the aromatic ingredients used in kyphi, the sacred incense burnt in temples along the Nile. Theophrastus, the ancient Greek botanist writing in the fourth century BC, described it as among the most aromatic of roots and noted its use in perfumery. Dioscorides listed it in his first-century materia medica as a treatment for digestive complaints, respiratory congestion, and inflammation.

2.2 Ayurveda (India)

Acorus calamus Linn. (Acoraceae), also known as Vacha in Sanskrit, is a mid-term, perennial, fragrant herb which is practiced in the Ayurvedic (Indian traditional) and the Chinese system of medicine. In Sanskrit, the Ayurvedic name Vacha literally translates to "speaking," referencing the herb's traditional use for improving speech clarity and cognitive expression.

Vacha was classified in Ayurveda as a Medhya Rasayana (brain tonic), as well as a Deepana (digestive stimulant) and Lekhana (fat-reducing agent). The Ayurvedic literature, including the Sushruta Samhita, lists two species of Acorus in the family Acoraceae as medicinal plants: A. calamus and A. gramineus.

The plant has been used to cure several diseases including asthma, fever, cough, epilepsy, hysteria, skin diseases, depression, hemorrhoids, diarrhea, insomnia, dysentery, kidney and liver problems, mental retardation, bronchitis, and as a sedative. The external application of the paste of A. calamus on rheumatism, inflamed joints, and rheumatic fever improves the pain and swelling in people.

2.3 Traditional Chinese Medicine (TCM)

Traditional Chinese Medicine knows calamus as Shi Chang Pu, where "chang" originally signified "splendid expression," linking the plant to mental clarity and communication. It has been used as traditional Chinese and Indian prescriptions for its beneficial effects on memory disorder, learning performance, lipid peroxide content, and anti-aging and anticholinergic activity.

2.4 Unani Medicine

In the Unani system of medicine, according to Ahmedullah bin Abdullah (1652), Jalinoos (Galen) described it as smelling like a horse and having a mild tingling effect on the tongue. Arabians placed this drug under the "mobehayat" (aphrodisiacs).

2.5 North American Indigenous Use

The natives of Alberta use A. calamus for the prevention of headache, toothache, hangover, and as a disinfectant for teeth. Sweet flag has a long history of use in Chinese, Nepalese, and Indian herbal traditions; sweet flag was and is used in herbalism by the Chipewyan people.

2.6 European History

Acorus calamus has been introduced in many European nations; for example, the Tatars introduced it to Poland in the 14th century AD. The famous botanist Clusius first cultivated it in Vienna in 1574 from a root obtained from Asia Minor. Leaves were used for thatching roofs and weaving baskets. From there, it expanded to France, Germany, and England around the end of the 16th century. Popular European books on medicinal plants tout calamus as a "wonder drug."

3. Phytochemistry: Key Constituents and Active Compounds

To date, 145 constituents have been isolated from this herb and identified, including phenylpropanoids, sesquiterpenoids, and monoterpenes.

3.1 Asarone Isomers (Principal Bioactives)

A number of active constituents from leaves, rhizomes, and essential oils of A. calamus have been isolated and characterized. Of the constituents, alpha- and beta-asarone are the predominant bioactive components.

α-Asarone, β-asarone ((E)-/(Z)-1,2,4-trimethoxy-5-prop-1-enylbenzene, CAS number: 2883-98-9/5273-86-9), and γ-asarone (1,2,4-trimethoxy-5-prop-2-enylbenzene, CAS number: 5353-15-1) are phenylpropenes which are biosynthesized via the shikimate pathway in several herbs, spices, and medicinal plants.

Major components of the essential oil are beta-asarone (as much as 75%), methyl isoeugenol (as much as 40%), and alpha-asarone, along with saponins, lectins, sesquiterpenoids, lignans, and steroids. Phytochemicals in the plant vary according to geographic location, plant age, climate, species variety, and plant component extracted.

In a published in vitro study, GC/MS analysis of the essential oil revealed that the major constituents were beta-asarone (79.54%) and alpha-asarone (8.47%).

3.2 Sesquiterpenes and Other Volatiles

The root essential oil contains monoterpene hydrocarbons, sesquiterpene ketones, trans (or α) asarone (2,4,5-trimethoxy-1-propenylbenzene), and β-asarone (the cis-isomer). Additional sesquiterpene components identified in the literature include shyobunone, isoshyobunone, calamusenone, and acorenone, compounds that contribute to the plant's characteristic aromatic profile.

3.3 Other Phytochemical Classes

The rhizome and leaves contain several phytochemical compounds, including phenylpropanoids, sesquiterpenoids, and monoterpenes, with α- and β-asarone and eugenol being predominantly present in the rhizome. The broader phytochemical inventory encompasses saponins, tannins, flavonoids, and various alkaloids.

4. Established and Proposed Mechanisms of Action

4.1 Acetylcholinesterase (AChE) Inhibition

The in vitro acetylcholinesterase inhibitory potential of the hydroalcoholic extract and of the essential oil from Acorus calamus rhizomes, and that of its major constituents, were evaluated using Ellman's method. GC/MS analysis of the oil revealed that the major constituents were beta-asarone (79.54%) and alpha-asarone (8.47%). The IC₅₀ values were obtained for the hydroalcoholic extract, the essential oil, beta-asarone, and alpha-asarone, and were 182.31±16.78 μg/mL, 10.67±0.81 μg/mL, 3.33±0.02 μM, and 46.38±2.69 μM, respectively. Physostigmine was used as the standard inhibitor with an IC₅₀ value of 0.28±0.015 μM. The experimental observations revealed that the AC essential oil and its constituents have significant AChE inhibitory potential, with beta-asarone showing the maximum inhibitory potential.

This mechanism is directly relevant to calamus's classical reputation as a memory- and cognition-enhancing herb, as AChE inhibition is the same pharmacological strategy used by approved pharmaceutical treatments for Alzheimer's disease such as donepezil.

4.2 Neuroprotection via NMDA Receptor Blockade and Antioxidant Activity

α-Asarone exhibits neuroprotective action through the blockade of the N-methyl-D-aspartate (NMDA) receptor and also has antioxidant properties. Administration of α-asarone has been shown to exert protective roles in various brain regions, such as the cerebral cortex, cerebellum, midbrain, hippocampus, and hypothalamus, particularly in noise-stressed rats, by normalizing increased superoxide dismutase and lipid peroxidation, and restoring decreased catalase, glutathione peroxidase, reduced glutathione, and vitamins C and E. Furthermore, α-asarone significantly ameliorated memory impairment in rats exposed to noise by inhibiting acetylcholinesterase activity in the hippocampus.

4.3 GABAergic Anticonvulsant Mechanism

Pre-inhalation of the essential oil of Acorus markedly delayed the appearance of pentylenetetrazole-induced convulsion by inhibiting the activity of gamma-amino butyric acid (GABA) transaminase. The same mechanism may be involved in the observed anticonvulsant activity profile.

4.4 Serotonergic Activity

The main objective of one experimental study on animal models was to evaluate the antidepressant action of Vacha (Acorus calamus). The behavioral study was conducted, and at the same time serotonin (5-HT) receptor involvement was evaluated. The experimental study was done in rats to evaluate Open Field Behavior (OFB), High Plus Maze (HPM) activity, and 5-hydroxytryptamine (5-HT) receptor syndrome, before and after feeding Vacha.

4.5 Anti-Inflammatory Activity

The A. calamus DMSO extract exhibited significant anti-inflammatory properties in BSA (bovine serum albumin) and EA (egg albumin) denaturation assays, similar to the standard diclofenac sodium. The anti-inflammatory potential of the A. calamus DMSO extract was further confirmed through the membrane stabilization assay.

4.6 Antimicrobial Activity

Acorus calamus L. rhizome hexane extract demonstrated broad-spectrum antibacterial activity against all isolates tested. India's ancient texts, the Charak Samhita and Sushruta Samhita, make reference to the traditional medicinal usage of A. calamus; in India and China, it has long been used to cure stomach aches, cuts, diarrhea, and skin conditions. The DMSO extract of A. calamus exhibited a significant inhibition zone against the pathogens Streptococcus mutans and Pseudomonas aeruginosa during the antimicrobial evaluation, surpassing the efficacy of the standard antibiotic; the time-kill curve assay validated the antibacterial efficacy, which was concentration-dependent.

4.7 Endoplasmic Reticulum (ER) Stress Suppression

The Asian traditional medicinal plant Acorus calamus and its component α-asarone exhibited various biological activities, including anti-inflammatory and antioxidant effects. In vitro effects of A. calamus extract and α-asarone on oxidative stress- and endoplasmic reticulum (ER) stress-induced cell death in hippocampal HT22 cells were investigated. Both A. calamus extract and α-asarone significantly suppressed cell death induced by the oxidative stress inducer l-glutamate and ER stress inducer tunicamycin. A. calamus extract and α-asarone also significantly reduced reactive oxygen species (ROS) production induced by l-glutamate.

5. Scientific Evidence by Area of Use

A critical review of the literature reveals that the overwhelming majority of evidence for Acorus calamus is preclinical — derived from animal models and in vitro (cell culture) studies. Human clinical trials are rare, generally small in scale, and often methodologically limited. Efficacy and safety in humans are still not known; preclinical evidence has not been systematically studied, and several pharmacological effects have been reported for extracts of Acorus calamus and propenylic asarone isomers.

5.1 Neurological and Cognitive Function

Traditional claim: Enhancement of memory, intellect, and speech; treatment of epilepsy, depression, and anxiety.

Preclinical (animal/in vitro) evidence: This is the best-studied area. Compelling evidence is suggestive of the biopotential of its various extracts and active constituents in several metabolic and neurological disorders, such as anticonvulsant, antidepressant, antihypertensive, anti-inflammatory, immunomodulatory, neuroprotective, cardioprotective, and anti-obesity effects.

In a rodent model of neuroinflammation, researchers assessed the effect of Acorus calamus on memory loss, anxiety, and antioxidant indices on neuroinflammation rat models. Different fractions of A. calamus were prepared; the subject rats were grouped in 11 groups of 10 each. In the nine treated groups, the extract gavage began 1 week before intraperitoneal injection of lipopolysaccharide (LPS) and continued for 2 weeks after the last injection of LPS. Behavioral tests, including passive avoidance and elevated plus-maze (EPM) tests, were run on days 24, 25, and 26. The oral administration of different fractions of A. calamus, especially the aqueous fraction, prevented memory deficits and stress through controlling oxidative stress and inflammatory processes.

In a separate rodent study examining social isolation stress, the study aimed to determine the antidepressant and antioxidative effects of AC on rats subjected to long-term social isolation-induced stress. The study involved 2-month-old male rats (24) weighing approximately 180–200 g bred in-house. The rats were divided into four groups (n = 6): Group 1 received saline, Group 2 received SIS, Group 3 received only 50 mg/kg AC, and Group 4 received 50 mg/kg AC and SIS for 6 weeks. After this, behavioral, biochemical, and neuronal assays were conducted. Behavioral experiments showed significantly higher activity levels (p < 0.001) in AC-treated rats than in the SIS group.

Human clinical evidence: There is one notable, small, uncontrolled clinical study. The investigation evaluated the role of 70% hydro-ethanolic extract of Vaca (Acorus calamus) on generalized anxiety disorder (GAD) in humans. Hamilton's Brief Psychiatric Rating Scale (BPRS) and thorough clinical investigations were used to screen the subjects. Thirty-three participants (20 male and 13 female; average age 36.2 years) were medicated with the extract in a fixed dose regime of 500 mg per capsule, twice daily, orally after meals. This study lacked a placebo control group and was small, making its conclusions preliminary.

A separate earlier clinical study referenced in the neuropharmacology literature (Tripathi AK, Singh RH. Clinical study on an indigenous drug vaca (Acorus calamus) in the treatment of depressive illness. J Res Ayur Siddha. 1995;16:24–34) reported on calamus in depression, but the study design details and outcomes are not fully accessible in modern indexed databases.

Evidence strength: Preliminary and largely preclinical. Animal and cell studies consistently show neuroprotective, anxiolytic, anticonvulsant, and memory-enhancing signals, but these cannot be extrapolated directly to humans. The one available human study on GAD is small and uncontrolled. No randomized controlled trials meeting modern standards have been completed.

5.2 Anticonvulsant Effects

Traditional claim: Treatment of epilepsy (Apasmara in Ayurveda) and seizure disorders.

Preclinical evidence: The rhizome of Vacha (Acorus calamus) has been used in Ayurvedic medicine for the treatment of various ailments such as epilepsy, headache, eye disorders, insomnia, and loss of memory. Previous studies demonstrated that Vacha rhizome has significant anticonvulsant activity against various induced seizure models in experimental animals. The anticonvulsant effect in animal models is proposed to operate via GABAergic pathways, specifically through inhibition of GABA transaminase.

Evidence strength: Preclinical only. No controlled human trials on calamus as an anticonvulsant have been published in indexed literature.

5.3 Digestive System

Traditional claim: Calamus has been used in traditional medicine for the treatment of digestive disorders and childhood colic.

Acorus calamus also shows antispasmodic, antidiarrheal, and cytoprotective properties in preclinical models. The volatile oil's antispasmodic activity on smooth muscle has been reported in in vitro studies.

Evidence strength: Traditional use backed by limited in vitro and animal evidence; no human clinical trials.

5.4 Cardiovascular System

Traditional claim: Treatment of vascular disorders, hypertension.

Various parts, especially the rhizome and roots, are sources of a range of bioactive phenolic compounds with beneficial effects on the cardiovascular system. A review article summarizing the current knowledge of the chemical composition of different parts of A. calamus and their roles in the prevention and treatment of cardiovascular diseases was published, but as no human studies have been performed, the review includes only in vitro and animal studies.

Evidence strength: In vitro and animal studies only; no human data.

5.5 Antimicrobial and Anti-Inflammatory Activity

Traditional claim: Treatment of infections, skin diseases, wound healing.

The A. calamus DMSO extract exhibited promising antioxidant, anti-inflammatory, and antimicrobial properties, supporting its traditional use in alternative medicine. A. calamus also has antimicrobial activity against bacteria and fungi, making it a candidate natural antibiotic.

Evidence strength: In vitro only. While multiple studies have consistently demonstrated antibacterial and anti-inflammatory activity in cell and biochemical assays, there are no human clinical trials in this area.

5.6 Metabolic Disorders (Hyperlipidemia, Obesity)

A small clinical Ayurvedic study examined Vacha in metabolic parameters: A clinical study was designed as a randomised single group open interventional trial. A total of 41 consenting patients of either sex were registered after screening for the trial, but 30 patients completed the course. Vacha Churna capsules of 500 mg were given twice daily with water before meals for 30 days. The results shown were described as highly significant. This study, however, lacked a control arm, was small and single-group, and results require confirmation in properly controlled trials.

Evidence strength: Very preliminary; single-arm uncontrolled design precludes firm conclusions.

5.7 Antitumor / Chemopreventive Activity

In recent years, phytochemicals from natural sources have been found to be important therapeutic targets for treatment of cancer and neurodegeneration. Acorus calamus (Sweet flag), and/or its bioactive phytochemical alpha- and beta-asarone, is a well-known drug in the traditional system of medicine which possesses anti-tumor and chemo-preventive activities as evident from numerous pre-clinical studies both in vitro and in vivo. Available scientific evidence for A. calamus and/or asarone for cancer chemoprevention is based on preclinical in vitro and in vivo models.

Extensive in-vivo studies are still necessary using various animal models to understand the molecular mechanisms. Critically, beta-asarone — one of the principal compounds — is itself associated with carcinogenicity in rodent models, which paradoxically complicates any anti-cancer development pathway.

Evidence strength: Preclinical only and deeply complicated by the established genotoxicity of the primary bioactive compound; no human evidence exists.

6. Body Systems and Health Areas Associated with Calamus

Vacha (Acorus calamus Linn.) is a traditional Indian medicinal herb practiced to treat a wide range of health ailments, including neurological, gastrointestinal, respiratory, metabolic, kidney, and liver disorders. The following body systems are represented in the pharmacological literature:

Central Nervous System: Memory, cognition, anxiety, depression, epilepsy, and general neurological health are the most extensively studied areas.
Gastrointestinal System: Digestive stimulation, antispasmodic effects, antidiarrheal activity, and treatment of colic.
Cardiovascular System: Antihypertensive, hypolipidemic, and cardioprotective effects, studied exclusively in preclinical models.
Respiratory System: Traditional use for asthma, bronchitis, and congestion.
Musculoskeletal System: External use for rheumatism and joint inflammation.
Integumentary System: Traditional use for skin diseases and wound healing.
Immune System: Immunomodulatory activity reported in animal studies.
Metabolic: Antidiabetic, anti-obesity, and hypolipidemic properties in preclinical models.

7. Dosage Forms and Dosages Reported in Studies

The following dosages are reported specifically in the research literature and are provided for reference purposes only, as reported by the cited sources:

Human clinical study (GAD): A 70% hydro-ethanolic extract of Acorus calamus at 500 mg per capsule, twice daily, orally after meals, in 33 adult participants.
Human clinical study (hyperlipidemia): Vacha Churna capsules of 500 mg given twice daily with water before meals for 30 days.
Animal study (antidepressant, rats): A dosage of 18 mg/kg of Vacha extract was used in rats; the rat dose was fixed as 8 times that of the human adult dose, also considering the percentage yield of Vacha extract after extraction.
Animal study (social isolation stress, rats): Rats weighing approximately 180–200 g were administered 50 mg/kg AC for 6 weeks.
Animal study (motor activity/CNS, mice): Dosages of 10, 25, and 50 mg/kg intraperitoneally of herbal extract antagonized spontaneous motor activity and also amphetamine-induced hyperactivity in mice.
In vitro (AChE inhibition): IC₅₀ values were 182.31±16.78 μg/mL for the hydroalcoholic extract, 10.67±0.81 μg/mL for the essential oil, 3.33±0.02 μM for beta-asarone, and 46.38±2.69 μM for alpha-asarone.

No standardized or consensus human dosage has been established in the peer-reviewed or regulatory literature. Efficacy and safety in humans are still not known.

8. Safety Considerations and Regulatory Status

8.1 The Beta-Asarone Problem: Genotoxicity and Carcinogenicity

The most critical and well-documented safety concern with Acorus calamus centers on beta-asarone, its primary bioactive constituent in most commercially available (Asian and European) varieties.

A comprehensive toxicological assessment revealed that cardiotoxicity, hepatotoxicity, reproductive toxicity, and mutagenicity as well as carcinogenicity were described for propenylic asarone isomers with varying levels of reliability.

Acorus is considered unsafe for human consumption by the Food and Drug Administration (FDA) because massive doses given to laboratory rats over extended time periods proved to be carcinogenic. Increased incidence of hepatomas was also observed in rats treated with β-asarone.

One study showed that β-asarone could cause duodenal cancer, inhibit the central nervous system, and cause hepatotoxicity, but the mechanism is unclear. Evidence demonstrates that asarone-mediated carcinogenicity has a direct interaction with DNA. An acceptable daily intake (ADI) for nutritional exposure cannot be derived for β-asarone because it causes genotoxicity.

8.2 Regulatory Bans and Restrictions

A. calamus and products derived from A. calamus (such as its oil) were banned from use as human food or as a food additive in 1968 by the United States Food and Drug Administration.

Regulatory bodies and expert committees have restricted or advised limits on the use of calamus/asarone-containing preparations. European scientific reviews have concluded that β-asarone is carcinogenic in rodents and should be minimised in flavouring and food uses, and fragrance-industry guidance (IFRA) sets conservative maximum levels for cis/trans-asarone in finished consumer products, with reported guidance for finished product concentrations of approximately 100 ppm/0.01%.

In the European Union, β-asarone and calamus oil are prohibited for seasoning purposes.

8.3 Skin Sensitization (Topical Use)

A comprehensive in vitro toxicological evaluation of A. calamus rhizome oil, using OECD-compliant new approach methods, classified the oil as a GHS Category 1B skin sensitiser and a Category 2 irritant, while demonstrating a non-corrosive profile.

8.4 Acute Toxicity: Nausea and Vomiting

Although calamus has been used for its fragrance and ingested, it has not been studied by rigorous clinical research. Individual medical reports of toxicity mention severe nausea and prolonged vomiting over many hours following oral uses. Laboratory studies of its extracts indicate other forms of toxicity, due mainly to the emetic compound β-asarone.

8.5 Reproductive Toxicity and Pediatric Reports

Mutagenicity attributed to various extracts and chemical constituents has been reported. Moderate reproductive toxicity has been reported. One study reports 3 neonates died following complications of vasambu (calamus) consumption.

8.6 Chemotype-Dependence of Toxicological Risk

Despite the number of ethnobotanical uses and reported bioactivities, the toxicological profile of A. calamus is heterogeneous and chemotype-dependent, and its toxicological profile remains insufficiently studied. The pharmacological and toxicological impacts of these plant materials suggest the overall toxicity profile of the extract of A. calamus has demonstrated cardiotoxic, hepatotoxic, reproductive toxic, mutagenic, and carcinogenic potential for propenyl asarone isomers.

The diploid North American variety is consistently reported to be free of detectable beta-asarone: The American variety is consistently tested free of the carcinogenic β-asarone, whereas the Asian varieties contain varying amounts of β-asarone. However, this variety may not be available in most commercial preparations, and buyers cannot readily verify ploidy or beta-asarone content without laboratory analysis.

8.7 Ayurvedic Shodhana Processing and Beta-Asarone Reduction

In Ayurveda, the rhizome is used only after a purification step (shodhana), in which it is boiled in media such as cow's milk. Analytical studies have reported that this processing significantly reduces the rhizome's β-asarone content, an effect attributed largely to volatilization of the heat-labile compound during prolonged boiling. The critical next step for calamus research is not more animal studies, but the development of a pharmaceutically standardized, quality-controlled, detoxified (Shodhita) Vacha product with a quantified, verifiably low level of β-asarone. Such a product could then be safely and ethically tested in well-designed, randomized controlled trials in humans to definitively establish its efficacy and safety for its primary indications, particularly in the realm of cognitive function.

References

Health Conditions

Health conditions that Calamus may help support.

No conditions available.

Body Systems

Body systems that Calamus may help support.

No body systems available.