English: Sweet flag, myrtle flag, sweet sedge

Hindi: Vacha

Sanskrit: Vacha, ugragandha

Sweet flag has long been known for its medicinal value. It originated in Europe but has been extensively used in Ayurveda, particularly to enhance memory. Vacha powder mixed with ghee is given ritually in India to newborn babies on the seventh day to improve the intellect and speech development. In China it is used in a similar way, to improve speech and aid recovery from stroke. The powder is sometimes blown into the nose of a patient in a coma to help regain consciousness. There are several polypoid varieties to be found, some of which do not contain the toxic constituent p-asarone, and these are preferable for medicinal use.

Habitat

A semi-aquatic plant growing in damp, marshy places throughout the world.

Botanical description

A perennial, aromatic herb with creeping rhizomes (Plate 3). The leaves are long, slender, sword-shaped and simple, arising alternately from the horizontal rhizomes.

These are longitudinally fissured with nodes, somewhat vertically compressed and spongy internally. Flowers small, fragrant, pale green in a spadix; fruits are a three-celled fleshy capsule.

Parts used

Rhizomes, rootstock.
Traditional and modem use

The rhizome is used in many different disorders, mainly as a nerve stimulant, to enhance memory and as an aromatic digestive. It is considered to be thermogenic, rejuvenative and sedative. Other uses for the plant include as a diuretic, expectorant, decongestant, antiinflammatory, aphrodisiac, anticonvulsant and antibacterial. It has also been used in the treatment of epilepsy, chronic diarrhoea, dysentery, bronchial catarrh, intermittent fever and certain tumours. Ayurveda recommends the use of vacha in the kidney and liver diseases, rheumatism and eczema. A poultice made of vacha is applied to paralysed limbs.

Ethnoveterinary usage

It is used in birds to get rid of lice; dusting the birds with dry powdered rhizomes kills lice within 12 hours. An infusion of the rhizome is used to wash newborn calves as a protection against vermin. It is also helpful in killing houseflies, repelling ticks and treating eye diseases in ruminants.

Major chemical constituents
Essential oil

ß-Asarone (isoasarone) is usually the major constituent but is present in highly variable proportions and occasionally absent. a-As arone, elemicine, cis-isoelemicine, cis and trans isoeugenol and their methyl ethers, camphene, P-cymene, ß -gurjunene, a-selin ene, ß -cadinene, camphor, terpinen-4-01, a-terpineol and a-calacorene, acorone, acorenone, acoragermacrone, 2-deca-4,7-dieno1, shyobunones, isoshyobunones, calamusenone, linalool and pre-isocalamendiol are also present.1,6,7,B

Others

Acoradin, galangin, 2,4,5-trimethoxy benzaldehyde, 2,5-dimethoxybenzoquinone, calamendiol, spathulenol and sitosterol have been isolated from Acorus calamusy,6

Medicinal and pharmacological activities

Antiulcer and cytoprotective activity: The ethanolic extract of the rhizome was studied in rats, for protection of the gastroduodenal mucosa against injuries caused by indomethacin, reserpine and cysteamine, and also in a pyloric ligation model. The extract produced a marked reduction in the volume and acidity of basal gastric secretions and ulcer index and helped to protect against chemically induced lesions. Antispasmodic activity: Experiments on the ileum, uterus, bronchial muscles, tracheal chain and blood vasculature showed the relaxant and antispasmodic activity of ß -asarone and the essential oil of the rhizome. The rhizome is useful in the treatment of diarrhoea and dysentery, combined with ginger for relief in flatulent colic.

Analgesic activity: The essential oil and alcoholic extract of the rhizome were shown to possess analgesic properties and also mild hypotensive and sedative action.

Antiinflammatory activity: An extract of the rhizome was studied in acute, chronic and immunological models of inflammation, including carrageenan-induced rat paw oedema, and compared with the activity of hydrocortisone. The extract showed significant antiinflammatory activity with a reduction of up to 44%. The essential oil is also an effective antiinflammatory agent and a coconut oil extract of the rhizome produced a 45% inhibition of carrageenan-induced rat paw oedema and 61 % inhibition using the granuloma pouch method.

Anticonvulsant activity: A polyherbal compound containing rhizome of Acorus calamus as one of the ingrediwts has been reported clinically to reduce epileptic attacks in patients by up to 50%. Treatment continued for 6 months resulted in cure in 66 out of 88 patients and no repeat episodes were reported after 2 years of the treatment. The isolated constituents of the rhizomes, asarone and ß-asarone, showed anticonvulsant activity in experimental models. There was a decrease in sociability scores with a reduction in anticholinergic action. Experiment on animal models also revealed the depressant action of the essential oils and the crude alcoholic and aqueous extracts of the rhizomes.

Antibacterial activity: Growth of cultured Gram-positive and Gram-negative organisms was inhibited significantly by an extract of the rhizome. A consistent and gradual decrease in replication of standard cultures of Staphylococcus aureus, Escherichia coli and Shigella flexneri was observed after treatment with the essential oil.

Safety profile

No health hazards or side effects are known with the administration of designated therapeutic dose, although ß-asarone is known to be carcinogenic in animals. It also induces vomiting in large doses.