Acorus calamus, commonly known as sweet flag or calamus, is a perennial wetland plant belonging to the Acoraceae family. Originally from Asia and Europe, this plant is now widespread across North America and other regions. It is recognized for its aromatic, sword-shaped leaves and a creeping rhizome that is highly valued in traditional medicine.

Botanical Classification

Kingdom: Plantae
Clade: Monocots
Order: Acorales
Family: Acoraceae
Genus: Acorus
Species: A. calamus

Plant Characteristics

Acorus calamus typically grows to about 1 meter in height. It features long, green, and sword-like leaves that emit a distinctive, sweet aroma when crushed. The plant produces small, greenish-yellow flowers on a spadix, enclosed by a leaf-like bract, during the late spring and early summer.

Chemical Composition and Structure

The rhizome of Acorus calamus contains several bioactive compounds, including asarone, eugenol, and methyl isoeugenol. These components are known for their neuroprotective, anti-inflammatory, and antimicrobial properties. Asarone, in particular, has been the subject of much pharmacological interest due to its sedative and psychotropic effects.

How to Cultivate It

1. Soil: Prefers wet, marshy soil conditions.
2. Light: Thrives in full sun to partial shade.
3. Water: Requires consistent moisture and can even grow in shallow water.
4. Temperature: Hardy in temperate climates, but can also tolerate colder conditions if the rhizomes are submerged or adequately mulched.

Uses and Benefits

Acorus calamus is extensively used in traditional medicine systems such as Ayurveda and Chinese medicine to treat digestive problems, respiratory issues, and nervous disorders. It is also utilized in the flavoring industry, particularly in the production of bitters and liqueurs, and as a natural insect repellent.

Applications

• Medicinal: Employed in various forms, including powders, tinctures, and teas, to treat an array of health conditions.
• Culinary: Used as a flavoring agent in certain traditional dishes and beverages.
• Aromatherapy and Perfumery: Essential oils derived from calamus are used in perfumes and as a part of aromatherapy for their calming effects.

Environmental and Safety Considerations

Acorus calamus is generally safe for cultivation and does not pose significant environmental threats. 

However, the use of its components, particularly asarone, should be cautious as it has been found to have neurotoxic effects at high doses. Therefore, regulatory limits are set in many countries regarding its use in food and medicine. 

Sustainable harvesting and cultivation practices are encouraged to maintain natural populations and ensure ecological balance.

References__________________________________________________________________________

Joshi RK. Acorus calamus Linn.: phytoconstituents and bactericidal property. World J Microbiol Biotechnol. 2016 Oct;32(10):164. doi: 10.1007/s11274-016-2124-2.

Abstract. Acorus calamus Linn. of the family Araceae (Acoraceae), commonly known as Sweet Flag and Vacha. The rhizome of this plant has medicinal properties against bugs, moths, lice and emetic stomach in dyspepsia. Chemical composition of the hydro-distilled essential oil obtained from the rhizomes of A. calamus was analyzed by gas chromatography equipped with flame ionization detector and gas chromatography coupled with mass spectrometry. The essential oil of A. calamus and its major compound β-asarone were tested against five Gram-positive, eight Gram-negative bacteria, and three fungi by the tube-dilution method at a concentration rang of 5.0-0.009 mg/mL. Forty constituents were identified which comprised 98.3 % of the total oil. The major compound β-asarone (80.6 %) was identified and confirm by NMR ((1)H- & (13)C-) in rhizome oil of A. calamus. The organism Micrococcus luteus was found to be more susceptible to the oil with minimum bactericidal concentration (MBC) value of 0.032 ± 0.004 mg/mL, followed by Aspergillus fumigatus, Aspergillus niger and Micrococcus flavus with MBC values of 0.104 ± 0.016, 0.117 ± 0.017 and 0.143 ± 0.013 mg/mL, respectively. The compound β-asarone was susceptible to the microorganism A. niger with MBC value 0.416 ± 0.065 mg/mL. The present study revealed that tetraploid variety of A. calamus is growing in this region with substantial amount of β-asarone. The oil showed bactericidal property against tested bacteria and fungi. The β-asarone exhibited poorer bactericidal activity against test microorganisms.

Uebel T, Hermes L, Haupenthal S, Müller L, Esselen M. α-Asarone, β-asarone, and γ-asarone: Current status of toxicological evaluation. J Appl Toxicol. 2021 Aug;41(8):1166-1179. doi: 10.1002/jat.4112.

 Khwairakpam AD, Damayenti YD, Deka A, Monisha J, Roy NK, Padmavathi G, Kunnumakkara AB. Acorus calamus: a bio-reserve of medicinal values. J Basic Clin Physiol Pharmacol. 2018 Mar 28;29(2):107-122. doi: 10.1515/jbcpp-2016-0132.

Abstract. Many plants are found to possess reliable pharmacological properties and have started to attract the attention of researchers. One such holistic plant is Acorus calamus, commonly known as sweet flag, belonging to the rhizomatous family Acoraceae. The different parts of this plant, such as the leaves and rhizomes, are used traditionally in different medicinal preparations for the treatment of various ailments including arthritis, neuralgia, diarrhoea, dyspepsia, kidney and liver troubles, eczema, sinusitis, asthma, fevers, bronchitis, hair loss, and other disorders. Many reports have also appeared in mainstream scientific journals confirming its nutritional and medicinal properties. Biochemical analysis of the plant has revealed a large number of secondary metabolites that may be responsible for its rich medicinal properties. Basic scientific research has uncovered the mechanisms by which itexerts its therapeutic effects. Medicinal herbs such as A. calamus are quite promising in the recent therapeutic scenario, with a large number of people favouring remedies and health approaches that are free from the side effects often associated with synthetic chemicals. In this review, we try to summarise the ethno-medicinal uses, botanical descriptions, phytochemical constituents, and biological activity of the plant parts, as well as the molecular targets of A. calamus, which we hope will serve as a good base for further work on this plant.

Sharma V, Singh I, Chaudhary P. Acorus calamus (The Healing Plant): a review on its medicinal potential, micropropagation and conservation. Nat Prod Res. 2014;28(18):1454-66. doi: 10.1080/14786419.2014.915827.

Abstract. Acorus calamus L., a tall, perennial, grass-like monocot plant from the Acoraceae family, is a well-known plant in Indian traditional medicines for centuries. It is a highly valued herb as it acts as a rejuvenator for brain and nervous system. It is a main medhya drug, which has the property of improving the memory power and intellect. Rhizomes of the plant are widely used in the treatment of number of ailments such as epilepsy, mental ailments, chronic diarrhoea, dysentery, fever, abdominal tumours, kidney and liver troubles, and rheumatism. A. calamus leaves, rhizomes and its essential oil possess many biological activities such as antispasmodic, carminative and are compiled in a simple approach in this review. This review presents a pragmatic description that deals with chemical constituents, toxicology, ethnobotany and pharmacological properties of A. calamus for easy and better understanding of the outstanding medicinal potential of this very special plant and sirens for its conservation.

Manikandan S, Srikumar R, Jeya Parthasarathy N, Sheela Devi R. Protective effect of Acorus calamus LINN on free radical scavengers and lipid peroxidation in discrete regions of brain against noise stress exposed rat. Biol Pharm Bull. 2005 Dec;28(12):2327-30. doi: 10.1248/bpb.28.2327.

Abstract. Exposure to continuous loud noise is a serious health problem due to excess production of oxygen free radicals. In medical research, more attention is paid to the antioxidant properties of medicinal plants to minimize the harmful effects of radicals. The aim of this study was to evaluate the protective effect of both ethyl acetate and methanolic extract of Acorus calamus LINN against noise stress (30 d, 100 dBA/4h/d) induced changes in the rat brain. We measured the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and the levels of reduced glutathione (GSH), vitamin C, vitamin E, protein thiols and lipid peroxidation (LPO) for the evaluation of oxidative stress status in discrete regions of the rat brain like cerebral cortex, cerebellum, pons-medulla, midbrain, hippocampus and hypothalamus. The results indicated that during exposure of noisy environment ROS generation led to increase in corticosterone, LPO and SOD, but decrease in CAT, GPx, GSH, protein thiols, vitamins C and E levels. Both the ethyl acetate and methanolic extract of Acorus calamus protected most of the changes in the rat brain induced by noise-stress.