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Malaysian Herbal Monograph
  • Written by Noorashikin Haleem
  • Updated on February 21, 2026

Jerangau rhizome

Acorus calamus Linn

Acoraceae

Figure 1 : A. calamus. (a) whole plant with adventitious root; (b) whole plant with rhizome; (c) leaves; (d) spike inflorescence; (e) adventitious root; (f) rhizome; (g) shredded rhizome; and (h) whole plant glasshouse establishment (Photos courtesy of MARDI, 2022).

Definition

Jerangau rhizome consists of the powder of dried rhizome of Acorus calamus Linn. (Acoraceae).

Synonym

Acorus elatus Salisb., Acorus undulates Stokes, Calamus aromaticus Garsault [1].

Vernacular names

Sweet flag, sweet root, calamus, sweet sedge, myrtle flag (English); jerangau, deringu, jerangoh, jeringau (Malay) [2, 3]; chang pu (Chinese) [4]; vasambu (Tamil) [5, 6].  

Character

Colour Light brown
Odour Aromatic
Taste Bitter and spicy

Identification

Plant Morphology

A perennial herb up to 80 cm tall, with a grass-like rhizome. Pseudostem erect, glabrous, grooved at one side, and ribbed at the opposite. Leaf simple, bright green, linear to sword-shaped, 40–95 cm long and 10–15 mm wide, thickened at the middle, distichous, acute, and with undulate margins. Inflorescence with a peduncle 20–25 cm long with a very narrow, unequal, short-acuminate spathe, and a green, cylindrical, obtuse spadix 5.0–6.5 cm long by 1.0–1.5 cm broad, densely flowered with bisexual flowers possessing a 6-lobed perianth, six stamens opposite the lobes, flattened filaments ca. 2 mm long, orbicular anthers less than 1 mm long, and a superior, conical, 2–3-loculed ovary. Fruits are small and berry-like, containing three or more seeds, indehiscent. Rootstock stout, with long fibrous roots, spreads horizontally or creeping below the surface of the soil. Seeds conical, 2 mm long [2, 3].

Microscopy

Powdered material consists of round-shaped to oval-shaped grain starches; elongated parenchyma; fragment and annular vessel; collenchyma cells; parenchyma cells, oil globules, and styloid crystal.

Figure 2 : Microscopic characters of A. calamus rhizome powder of 0.355 mm size. (a) Elongated parenchyma (blue arrow) (magnification 40x); (b) fragment vessel (purple arrow) (magnification 40x); (c) variation of starch grains  (oval shape: yellow arrow; round shape: red arrow) (magnification 40x); (d) collenchyma cells (orange arrow) (magnification 40x); (e) annular vessel (pink arrow) (magnification 40x);  (f) styloid crystal (green arrow) (magnification 40x); and (g) cluster of oil globules (yellow arrow) (magnification 40x). [Scale bars: a–f = 50 µm; g = 100 µm]

Chemical Tests

Observed colour of solution after treatment for the presence of

Test for the presence of triterpenesBluish green
Test for the presence of steroidsWhite precipitate
Test for the presence of saponinsRed

Thin Layer Chromatography (TLC)

Test solutionWeigh about 1.0 g of A. calamus dried rhizome powder of 0.355 mm size in a 20-mL glass vial. Add 10 mL of methanol and sonicate the mixture for 30 min. Filter the mixture solution with a 0.22-µm nylon membrane syringe filter into vials. Dilute 10 times by mixing 1 volume of filtrate with 9 volumes of methanol. Use the diluted filtrate as test solution.
Standard solutionDissolve β-asarone [CAS no.: 5273-86-9] in methanol to produce a standard concentration of 1.0 mg/mL.
Stationary PhaseHPTLC silica gel plate 60 F254, 10 x 10 cm
Mobile phaseHexane : ethyl acetate; (4 : 1) (v/v)
Application

(a) β-asarone solution (S); 3 µL, as a band

(b) Methanol extract of A. calamus dried rhizome powder (L); 3 µL, as a band

Development distance8 cm
DryingAir drying
Detection

(a)   UV at 254 nm before derivatisation;

(b)   UV at 366 nm before derivatisation;

(c)   Visible light after derivatisation with p-anisaldehyde reagent.

Figure 3 : TLC chromatogram of β-asarone (S) and methanol extract of A. calamus dried rhizome powder (L) observed under (a) UV at 254 nm before derivatisation, (b) UV at 366 nm before derivatisation, and (c) visible light after derivatisation with p-anisaldehyde reagent.

High Performance Liquid Chromatography (HPLC)

Test solutionWeigh about 1.0 g of A. calamus dried rhizome powder of 0.355 mm size in a 20-mL glass vial. Add 10 mL of methanol and sonicate the mixture for 30 min. Filter the mixture solution with a 0.22-µm nylon membrane syringe filter into vials. Dilute 10 times by mixing 1 volume of the filtrate with 9 volumes of methanol. Use the diluted filtrate as test solution.
Standard solutionDissolve β-asarone [CAS no.: 5273-86-9] in methanol to produce a standard concentration of 1.0 mg/mL.
Chromatographic system

Detector: 280 nm

Column: C18 (2.6 µm, 3 mm I.D x 150 mm)

Column oven temperature: 30°C

Flow rate: 0.6 mL/min

Mobile phase

(gradient mode)

Run Time (min)

A-

Water (%)

B-

Acetonitrile        (%)

07030
157030
202080
257030
Run time25 min
System suitability requirements

Perform at least five replicate injections of the β-asarone (1.0 mg/mL). The requirements of the system suitability parameters are as follow:

  1. Symmetry factor (As) for β-asarone is not more than 1.5.
  2. Percentage of relative standard deviation (RSD) of the retention time (tr) for β-asarone is not more than 2.0%.
Acceptance  criteria 
  1. Retention time (tr) of β-asarone in the test solution is similar to the tr of the standard solution.
  2. The ultraviolet (UV) spectrum of β-asarone in the test solution is similar to the UV spectrum of β-asarone in the standard solution (optional supportive data).

(b)

(a)

Figure 4 : Whole HPLC chromatogram of (a) β-asarone standard solution (1.0 mg/mL) at tr = 13.032 min and (b) methanol extract of A. calamus dried rhizome powder showing peak corresponding to β-asarone standard at tr = 13.031 min.

(b)

(a)

Figure 5 : HPLC chromatogram highlighting the elution region of (a) β-asarone standard solution (1.0 mg/mL) at tr = 13.032 min and (b) methanol extract of A. calamus dried rhizome powder showing peak corresponding to β-asarone standard at tr = 13.031 min.

Figure 6 : UV spectrum of β-asarone standard solution (1.0 mg/mL) and methanol extract of A. calamus dried rhizome powder.

Purity Test

The purity tests, except foreign matter test, are based on A. calamus dried rhizome powder of 0.355 mm particle size.

Foreign  Matter
 Not more than 2%
Ash Contents
Total ashNot more than 5%
Acid-insoluble ashNot more than 1%
Water-soluble ashNot more than 2%
Loss on Drying
 Not more than 14%
Extractive Values
 Water-soluble extracts
Hot methodNot less than 13%
Cold methodNot less than 7%
Ethanol-soluble extracts
Hot methodNot less than 5%
Cold methodNot less than 2%

Safety Test

The safety tests are based on G. species dried plant part powder of 0.355 mm particle size.

Heavy Metals
ArsenicNot More than 5.0mg/kg
MercuryNot More than 0.5 mg/kg
LeadNot More than 10.0 mg/kg
CadmiumNot More than 0.3 mg/kg
Microbial limits
Total bacterial countNot more than 105 cfu/g
Total yeast and mould countNot more than 104 cfu/g
Bile-tolerant gram negativeNot more than 104 cfu/g
Specific Pathogens
Salmonella spp.Absent in 25 g
Escherichia coliAbsent in 1 g
Staphylococcus aureusAbsent in 1 g
Pseudomonas aeruginosaAbsent in 1 g

Chemical Constituents

Ethanol extract of A. calamus dried rhizome was found to contain phenylpropanoid (e.g., β-asarone) [7] and sesquiterpenes (e.g., neo-acorane A, acoric acid, and calamusin D) [8]. The volatile oil of A. calamus dried rhizome contains phenylpropanoids (e.g., β-asarone, α-asarone, β-methyl isoeugenol, and β-isoelemicin) and sesquiterpenes (e.g., 6-epishyobunone, eudesma-4,7-dien-1-beta-ol, caryophyllene oxide, β-guaiene, and 3-(2-isopropyl-5-methyphenyl)-2-methyl-1-propanol) [9]. The volatile oil of A. calamus fresh rhizome contains phenylpropanoids (e.g., β-asarone, α-asarone, γ-asarone, β-methyl isoeugenol, α-methyl isoeugenol, methyleugenol, euasarone, cis-asarone, and trans-asarone), monoterpenes (e.g., limonene, 1,8-cineole, linalool, camphor, menthol, (E)-3,7-dimethyl-1,3,6-octatriene, trans-methyl-iso-eugenol, and α-calacorene), and sesquiterpenes (e.g., (E)-caryophyllene, β-gurjunene, δ-cadinene, kessane, elimicin, cis-calamenen-10-ol, shyobunol, asaraldehyde, isocalamendiol, aspidinol, α-cedrene, β-elemene, shyobunone, bicyclo-germacrene, and dehydroxy-iso-calamendiol) [10, 11, 12].

Medicinal Uses

Uses described in folk medicine, not supported by experimental or clinical data

Traditionally, the rhizome of this plant has been used to induce vomiting [13] and to relieve throat and digestive issues, including diarrhoea [14]. The dried rhizome is mixed with clay and water to make a paste, which is traditionally believed to protect against smallpox. A decoction of the rhizome, when boiled and sprayed around the patient’s bed, is thought to prevent the disease from spreading [15]. The root is used to treat intermittent fever [16].

Biological and pharmacological activities supported by experimental data

Anthelmintic activity Methanol extract of A. calamus dried rhizome (800 mg/kg) showed 62.30% reduction in faecal egg counts (EPG) and 83.25% reduction in worm counts at necropsy of rats on day 39 compared to praziquantel-control (85% reduction in EPG counts and 81% reduction in worm burden of animals) anthelmintic assay [17].
Insecticidal activity Compounds (α-asarone, methyleugenol, and (E)-methylisoeugenol) isolated from essential oil of A. calamus dried rhizome exhibited contact toxicity against the booklice, L. bostrychophila (half lethal dose 50% (LD50): 125.73, 103.22, and 55.32 µg/cm2) compared to pyrethrum-control (LD50: 18.99 µg/cm2) using insecticidal assay [8].
Anti-inflammatory and hepatoprotective activity Hydroethanolic extract of A. calamus rhizome were administered orally (125, 250, and 500 mg/kg body weight) once daily for 28 days to rheumatoid arthritis-associated liver injury in Wistar rats. Findings reported significant (p < 0.05) numerical improvements in liver function markers; at the 500 mg/kg dose, alanine aminotransferase (ALT) levels dropped from a diseased state of 95.42 U/L to 48.21 U/L, while aspartate aminotransferase (AST) levels decreased from 158.34 U/L to 82.15 U/L compared to methotrexate (ALT reduced to 45.18 U/L; AST to 79.44 U/L) [18].
Neuroprotection activity Powder of A. calamus mixed with water was administered orally (50 mg/kg) to socially isolated rats for 6 weeks. Findings showed significant (p < 0.01) behavioural changes, reducing the immobility time in the Forced Swim Test from a baseline of 148.5 seconds in the stressed group down to 82.3 seconds. Furthermore, the treatment significantly (p < 0.05) reversed oxidative stress by increasing superoxide dismutase (SOD) levels from 4.2 U/mg protein in isolated rats to 7.8 U/mg protein, demonstrating its efficacy compared to the normal saline control [19]. Ethanolic extract of A. calamus was administered orally (200 mg/kg) to valproate-induced autism in Wistar rat pups for 15 days. Findings reported significant (p < 0.001) histopathological improvements, specifically a 42% reduction in the number of degenerating (pyknotic) neurons in the cerebellar Purkinje cell layer compared to the untreated autistic group. The treatment effectively restored neuronal density to near-normal levels, providing numerical proof of its ability to mitigate structural brain damage [20].
Cardioprotective activity Ethanolic extract of A. calamus was administered orally (100 and 200 mg/kg) to isoproterenol-induced albino Wistar rats (male; 180-250 g) for 30 days. Findings reported significant decrease in nitric oxide serum (100 mg/kg: 26.53%, p < 0.05; 200 mg/kg: 28.52%, p < 0.01) compared to amlodipine (9 mg/kg: 29.75%) [21]. Ethanolic extract of A. calamus was administered orally (100 and 200 mg/kg) to isoproterenol-induced albino Wistar rats (male; 180-250 g) for 30 days. Findings reported significant decrease in lactate dehydrogenase serum (100 mg/kg: 17.82%, p < 0.05; 200 mg/kg: 20.49%, p < 0.01) compared to amlodipine (9 mg/kg: 22.30%) [21]. Ethanolic extract of A. calamus was administered orally (100 and 200 mg/kg) to isoproterenol-induced albino Wistar rats (male; 180-250 g) for 30 days. Findings reported significant decrease in thiobarbituric acid-reactive substance level (100 mg/kg: 13.79%, p < 0.05; 200 mg/kg: 16.14%, p < 0.01) compared to amlodipine (9 mg/kg: 16.82%) [21].

Clinical studies

A clinical trial evaluated the efficacy of A. calamus as a cognitive enhancer in 60 children aged 7-11 years through an oral intervention of 250 mg rhizome powder capsules administered twice daily (after breakfast and dinner) for a duration of 48 days. The study reported significant improvements in memory scores, which increased from a baseline mean of 11.00 to 14.33 post-intervention (p < 0.001), and academic performance, with school test scores rising from a mean of 12.50 up to 15.80 (p < 0.05). Furthermore, concentration levels and attention spans showed significant (p < 0.001) gains compared to the placebo group, which received 250 mg of Dextrin. Throughout the 48-day period, no clinical signs of toxicity or adverse events were observed, supporting the safety of the rhizome powder at this specific dosage [22].

Safety Information

Preclinical studies (Toxicology study)

14-day acute toxicity Ethanol (95%) extract of A. calamus dried rhizome (175, 550, 750, 1,750, and 5,000 mg/kg body weight) administered orally to Wistar albino rats (female; 8–10 weeks old; 150–200 g body weight) for 14 days showed no significant changes were observed in gross necropsy. Tremors, piloerection, and abdominal breathing were observed immediately after oral administration of 1,750 and 5,000 mg/kg body weight. The LD50 was reported to be greater than 5,000 mg/kg body weight [23]. Methanol extract of A. calamus dried rhizome (2,000 mg/kg) administered orally to Swiss albino mice (female; 180–200 g body weight) for 14 days did not showed any changes of body weight or reveal any signs of toxicity or mortality. The LD50 was found to be greater than 2,000 mg/kg body weight [24]. Raw A. calamus rhizome and shade-dried A. calamus rhizome (175, 550, and 2,000 mg/kg) administered orally to Charles Foster strain albino rats (female; nulliparous; non-pregnant; 10–12-week-old; 130–180 g) for 14 days did not produce any observable toxic effects. The LD50 was found to be greater than 2,000 mg/kg body weight [25]. 90-day chronic toxicity Ethanol (95%) extract of A. calamus dried rhizome (200, 400, and 600 mg/kg body weight) were administered daily, orally, to Wistar albino rats (female and male; 5–6 weeks old; 100–190 g body weight; n = 5 per sex per group) for a duration of 90 days. No clinical signs or mortality were observed, and body weight, feed intake, haematological, and biochemical parameters showed no significant changes (p > 0.05) compared with the untreated control group. Pathological examination revealed no significant differences (p > 0.05) in organ weights or histopathological findings between treated and control rats. The safety dose was determined to be 600 mg/kg body weight [23].

Others (Adverse reaction, contraindication, side effect, warning, precaution)

Warning Regulatory authorities and scientific committees have issued stringent warnings regarding the use of A. calamus (sweet flag) due to significant safety risks. The European Commission’s Scientific Committee on Food (SCF) has determined that β-asarone, a major constituent found in certain varieties of the plant, is genotoxic and carcinogenic, recommending that human exposure be kept as low as possible [24]. This assessment is supported by recent toxicological reviews confirming that the volatile oil of A. calamus contains various asarone isomers which exhibit mutagenic and hepatotoxic potential [26]. Consequently, the United States Food and Drug Administration (FDA) has classified calamus, including its oil and extracts, as a prohibited substance that is not permitted for use in human food [27]. Beyond its carcinogenic risks, clinical resources caution that oral consumption can lead to severe adverse effects, including kidney damage, liver toxicity, and seizures; it is specifically contraindicated during pregnancy and breastfeeding due to the risk of uterine contractions and potential harm to the developing fetus [28].

Dosage

Information and data have not been established.

Storage

Store below 30°C. Protect from light and moisture.

Reference

 

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  4. Chinese Pharmacopoeia Commission. Pharmacopoeia of the People’s Republic of China. 2015 ed. Vol. 1. Beijing: China Medical Science Press; 2015.
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  11. Liu XC, Zhou LG, Lin ZL and Du SS. Identification of insecticidal constituents of the essential oil of Acorus calamus rhizomes against Liposcelis bostrychophila Molecules. 2013;18:5684–5696.
  12. Rita WS, Kawuri R, Swantara IMD. The essential oil contents of jeringau (Acorus calamus) rhizomes and their antifungal activity against Candida albicans. Journal of Health Science and Medicine UNUD Journal. 2017;1(1):33–38.
  13. Srivastava TN, Rajasekharan S, Badola DP, Shah DC: An index of the available medicinal plants usedin Indian system of medicine from Jammu and Kashmirstate. Ancient Science of Life. 1986;6(1):49–63.
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  18. Bari MU, Aslam B, Muhammad Naeem F, Hussain A, Majeed W, Alhindary IA, Abdelrahman SH, Taricone S. The protective effects of Acorus calamus rhizome extracts against rheumatoid arthritis-associated dyslipidemia, oxidative stress, and liver injury in rats. Journal of Applied Animal Research. 2024;52(1).
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  21. Singh BK, Pillai KK, Kohli K, Haque SE. Isoproterenol-induced cardiomyopathy in rats: influence of Acorus calamus A. calamus attenuates cardiomyopathy. Cardiovascular Toxicology. 2011;11(3):263–271.
  22. Huddar S, Kumar EA. Clinical evaluation of vacha rhizome (Acorus calamus Linn) as Memory Booster in Children. Ayushdhara. 2023;10(5):67–73.
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