Keywords

13.1 Introduction

Acorus calamus Linn. – often called as sweet flag – belongs to the family Acoraceae. It is also called as Acorus odoratus. The name of genus Acorus is derived from Acoron (coreon means the pupil of the eye) and the species name calamus is derived from the Greek word calamus (a reed). There are 110 genera in the family Acoraceae and beyond 1800 species. The family comprises bulbous or rhizomatous herbs. In Kashmir, it is locally known by the name Vai-gander. Its rhizome is cut into small circular pieces, dried and made into a garland and is as such sold in market. Traditionally the rhizome portion is used for the treatment of cough, stomachache, swellings, fever, toothache diarrhea and Joint pain etc. (Rather and Baba 2015). The rhizome is also used as abortifacient, carminative, diaphoretic, febrifuge, stimulant and vermifuge (Devi et al. 2014). In commerce it occurs in both peeled and unpeeled forms. It produces flowers during summer season depending on the latitude, in the Himalayas, Manipur, and Naga Hills and in some parts of south India. The other species in this genus is Acorus gramineus native to Eastern Asia commonly called as Japanese sweet flag, Japanese rush, dwarf sweet flag is a wetland perennial with grass like foliage. However, A. calamus is a semi aquatic plant species, grows in a specific area only. The species is close to extinction because of excessive exploitation and loss of habitat (due to filling of wetlands) (Barbhutiya et al. 2009) and un-favored reproductive system.

13.2 Taxonomic Position

A. calamus belongs to a genus of monocot flowering plants. This genus was formerly set down in the Araceae family. However, the latest classifications have placed it in its own recognized family Acoraceae and order Acorales. This is the only genus of the ancient live line of monocots. Presently Acorus is regarded as “colleague” to all other monocots. Lilloposida stands for one cotyledon and the cotyledon is having two prominent vascular bundles. Leaf venation is mostly parallel, and closed at the apex. Vascular bundles are usually without cambium. So these species are usually herbs. Their flowers are usually tri-merous, sometimes tetra-merous. Liliopsida most probably originated from some very ancient vesselless herbaceous member of Magnoliopsida that had atactostelic vascular system means a highly developed stele (Takhtajan 2009).

  • Class: Liliopsida; Order; Acorales; Family: Acoraceae; Genus: Acorus; Species: calamus

  • English name: Sweet Flag, Local name: Vai-gander

13.3 Morphological Characteristics

It is a perennial wetland, liliopsid plant, with creeping and divided, scented rhizome, circular, with thickness of 2.5 cm, light brown to brown from external surface and white from interior side. The leaf of A. calamus has a single eminent mid-vein and moderately elevated secondary and tertiary veins (Bentley and Trimen 1983). This feature makes it different from A. americanus. The leaves are sword-shaped, 0.7 to 1.7 cm wide. The margin of the leaf is clearly edged. During the late spring numerous tiny, greenish yellow flowers are borne on 5–10 cm long spadex which grows from the sympodial leaf of A. calamus (Fig. 13.1). The sympodial leaf is somewhat shorter than the vegetative leaves. The fruits are small and berry-like, containing few seeds.

Fig. 13.1
figure 1

Summer and autumn view of Acorus calamus

Full size image

13.4 Geographic Distribution

A. calamus L. is a semi-aquatic plant found throughout the temperate to sub-temperate regions of Eurasia and America. The plant has an ethnobotanical history dating back possibly to the time of Moses in the Old Testament of the Bible and was used in early Greek and Roman medicine. A. calamus, which is supposed to be native to India and have roll out through trade routes to other countries Motley et al. (1994). It grows in wet lands of Kashmir valley particularly in Hokhersar and Shalbug wetlands (Ganderbal), Manasbal Lake, Anchar Lake Srinagar and other marshy tracts in huge quantities (Sharma et al. 1985). A. calamus has a great geographical distribution in India from Kashmir to the North-East with an altitudinal range of 1500–2200 m in the Himalayas. Therefore, presence of distinct A. calamus varieties in various habitats, provides the expectations or chances of elevated population disparity particularly with regard to ploidy level and active component β-asarone (Ogra et al. 2009). Various varieties of A. calamus have been recognized on the bases of poloidy level and geographical or topographical distribution. These varieties are (i) diploid (2n = 2x = 24; North America), (ii) triploid (2n = 3x = 36; Europe), (iii) the tetraploid (2n = 4x = 48; East Asia, India and Japan) and (iv) hexaploid (2n = 6x = 72; Kashmir area) (Ogra et al. 2009; Ginwal et al. 2011). Ginwal et al. (2011) studied a good number of populations of A. calamus from discrete areas of India and reported that populations from Kashmir valley were all hexaploids (2n = 6x = 72) and the one population A-44 from Khaziar lake (Himachal Pradesh) was diploid (2n = 2x = 24). All other populations were triploid and tetraploids.

The striking feature is that only diploid and hexaploids varieties are known to have low concentration of β-asarone, a carcinogenic agent. Some authors have reported contrasting chromosome number in this plant species and corresponded its ploidy status with the amount of active component β-asarone. For instance: A. calamus variety from Jammu region possesses a tetraploid 2n = 48 = 4x number of chromosomes and about 80% β – asarone, 13% α-asarone level in their oil. In contrast A. calamus variety from the Kashmir region is having the hexaploids 2n = 54 = 6x number of chromosomes and very little quantity i.e. 5.2% of the asarone level in their oils. Similarly, the cylindrical root as well as the leaves of the diploid variety 2n = 24 = 2x is known by the absenteeism of β-asarone and the triploid populations 2n = 36 = 3x identified by the appearance of 3–19% β-asarone in the rhizome oil and 31–44% in the leaf top oil; however, the tetraploids accommodate up to 96% of β-asarone in their rhizome oils and 60–70% in their leaf-top oils and 60.92–8.0%.

The tetraploids from Japan and far-east Russian are characterized by the presence of 10–40% of β –asarone in rhizomes and 20–50% β –asarone in their leaf top oils. The populations of A. calamus from Kashmir are genetically distinct as well as possess the low concentration of carcinogenic β-asarone in their essential oil. The germ plasm of A. calamus from Kashmir is having good potential for huge augmentation for commercial cultivation. There is very less flow of genes in between the populations of A. calamus (diploid variety) of Kashmir region, which is a great tool in retaining of the genetic variations in the populations (Ginwal et al. 2011). It is a famous endangered aromatic and medicinal herbaceous plant species mostly found in Kashmir region of Jammu and Kashmir, India and also in China. (Avadhani et al. 2016). This plant species due to habit loss caused by drying up of wet lands have become rare in various pockets of the world (Dusek et al. 2007). It is a customary commodity in the world wide drug trade and the basic material is procured from the natural resource. In an International report conveyed by McAlpine Thorpe and Warrier Limited (1996), A. calamus is amidst the endangered therapeutic plant species whose population has been reported to decrease drastically.

13.5 Chemical Composition

So far nearly 145 compounds have been isolated from A. calamus rhizomes and leaves, viz. sterols, phenylpropanoids, glycosides, triterpene, triterpenoid sesquiterpenoids, saponins, alkaloids and monoterpenes. Amidst these, sesquiterpenoids and phenylpropanoids (chiefly, asarone and eugenol) have been reported as the primary efficient compounds (Sharma et al. 2020). Phenylpropanoids of A. calamus are with a skeletally divergent group of phenylalanine- derived secondary plant metabolites, like eugenol, α-asarone, β-asarone, isoeugenol, etc. (Soledade et al. 2010). A number of phenylpropanoids have been identified from A. calamus rhizome and leaves. α and β-asarone isolated from the rhizome are the prominent compounds present in this plant. A good number of aromatic oils with different structures have also been communicated from the rhizome part of the plant (Kumar et al. 2010; Kim et al. 2011; Haghighi et al. 2017).

The major chemical constituents of the essential oils of sweet flag are thermolabile squiterpenoids, phenylpropanes, mono-terpenesandphenylpropanes (Rost 1979; Bos 1979). Methyleugenol, cis- methylisoeugenol, geranylacetate, 3-asarone, f-farnesene, epishyobunone, shyobunone, isoshyobunone are the most prominent chemical constituents comprising approximately 20% of the volatile oil (Rost 1979; Bos 1979). The rhizomes oil of A. calamus contain β-Asarone (83.2%) and α-asarone (9.7%) as the major constituents, while as the leaf oil contain β-asarone (85.6%) and linalool (4.7%) as the major constituents (Oprean et al. 2001; Raina et al. 2003).

The oil from rhizome was found to contain varying concentrations of camphor, a-asarone, b-asarone, c-asarone, calamene, calamenenol, calameone, a-pinene b-pinene, camphene, p-cymene, eugenyl acetate, eugenol, isoeugenol, methyl isoeugenol, calamol, azulene, eugenol methylether, 1,8-cineole, dipentene, terpinolene, methyleugenol, saronaldehyde, hydrocarbonsanda-caryophyllene (Nigam et al. 1990; Srivastava et al. 1997; Mukherjee 2002). The oil also contains fatty acids such as heptylic acid, an ester of butyric acid, palmitic acid and its ester (Chaudhury et al. 1957). A lignin called as acoradin was isolated from the rhizomatous portion of the plant species (Raja et al. 2009). Imam et al. (2013) took studies of photochemistry of rhizome and revealed the existence of flavonoids, glycosides, saponins, tannins, mucilage, volatile oil, polyphenolic compounds and pungent principle. The plant also contains glycoside, alkaloid and essential oil containing calamen, clamenol, calameon, asarone and sesquiterpenes and a bitter glycoside named acorine along with eugenol, pinene and camphene. Satyal et al. (2013) in Nepal reported (Z) asarone (78.1–86.9%), (E)-asarone (1.9–9.9%), (Z)-methyl isoeugenol (1.5–2.0%), linalool (0.2–4.3%) and small amounts of gamma-asarone (2.0–2.3%), in the essential oil of rhizome extract of the mentioned plant species.

13.6 Contribution of A. calamus L. to a Rural Livelihood-Based Cottage Industry in Kashmir

Of the all off-farm and on-farm income sources in District Ganderbal of Kashmir, in district Ganderbal of Kashmir, the total average collection/household/annum of A. calamus was 67.3 kg. From this a total average of 61.7 kgs, were processed and an average of 5.1 kgs were consumed by per family household providing a total average employment of 68.66 man days to the single sample household or an average income/household/annum as Rs. 2152.00 in the district. So the Acorus based cottage industry has been found as the fifth major source for generation income in the District Ganderbal of Kashmir. Usually of marginal landholders living in the vicinity of wetlands go for collection and sold it at the rate of Rs. 34 kg−1 (Bhat et al. 2020).

13.6.1 Ethnomedicinal Uses

Locally all parts of the plant are used for treatment of one or other ailment. Mostly rhizome is dried and grounded into powder and the powder is utilized for treatment of skin diseases, wounds, urinary infections, deworming, gastrointestinal disorders, joints pains, stomachache, gout, burns and cough etc. In Ayurveda medicine, A. calamus, an excellent herbaceous plant species, is regarded as refresher or renovator for the brain and nervous system and also used for treatment of various digestive disorders. The cylindrical roots of A. calamus are utilized for a number of medicinal purposes particularly loss of appetite, stomachache, fever as well as toothache (Divya et al. 2011). This plant species is utilized generally in the Indian Ayurvedic tradition, as well as in the Chinese system of medicine for anodyne, febrifuge, tonic, anti-depressant, anti-obesity, and analeptic purposes; it is highly therapeutic for skin diseases. It is also utilized for treatment of neurological, respiratory, gastrointestinal, and various other health ailments. Rhizomes and leaves are found to be profusely practiced in the form of infusion, powder, paste, or decoction (Kingston et al. 2009; Napagoda et al. 2019). All these properties are due to the presence of active components like glycosides, saponins, resins and steroids.

Sharma et al. (2020) reported that A. calamus is a conventional Indian scented medicinal herb that is used to cure a large range of health disorders, like gastrointestinal, neurological, metabolic, respiratory, kidney, and liver diseases. They also reported that about 145 components are present the herb and have been isolated and identified. They include sesquiterpenoids, phenyl propanoids, and monoterpenes as well. A large number of evidence supports the bio-potential nature of its various extracts and active constituents in many neurological and metabolic diseases. The scented rhizomes of A. calamus are utilized considerably in conventional medicine internationally. These are regarded to hold anthelmintic and anti-bacterial properties and also utilized for cure of tumors, persistent diarrhea, stomach pain, dysentery acute rhinitis, chest diseases and fevers (Rani et al. 2003).

The phenylpropanoid β-Asarone, one of the power full components isolated from the roots and rhizomes of A. calamus was found to have antibacterial and anthelmintic activity (McGaw et al. 2002). The anticonvulsant property exhibited by volatile oil from rhizomes of A. calamus has also been attributed to the presence of β-Asarone in significant amounts (Mittal et al. 2009; Ponrasu et al. 2014). β-asarone easily passes through the blood-brain-barrier (BBB) and shows significant pharmacological effects on the cardiovascular and central nervous systems (Sadati et al. 2016).

13.6.2 Anti-bacterial Activities

The plant extract has antibacterial properties on all gram negative and gram positive bacteria and thus is convenient for the development of potent treatment for the eradication of contagious diseases. The ethanolic extract of rhizomes possesses very strong antibacterial activity against different strains of bacteria like A. hydrophila, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa (Bhuvaneswari and Balasundaram 2006).

13.6.3 Hypolipidemic Properties

The saponins found in the ethanolic extract of A. calamus demonstrate hypolipidemic properties. The concentrated aqueous extract of A. calamus has also demonstrated hypolipidemic activity (Sharma et al. 2014).

13.6.4 Hyperglycemia

According to Si et al. (2010), A. calamus improves post prandial hyperglycemia and cardiovascular complications.

13.6.5 Allelopathy

The aqueous extract of A. calamus has been observed to demonstrate allelopathic effects on the development of Microcystis aeruginosa and Chlorella pyrenoidosa, the two water bloom-forming algal species (Hur et al. 2004).

13.6.6 Anticancer Activity

Gaidhani et al. (2009), evaluated anticancer activity of A. calamus rhizomes by preparing concentrates of root of Glycyrrhiza glabra, rhizome of A. calamus, and Terminalia chebula. The β-asarone, has cancer causing property. It has shown anti carcinogenic activation of α-asarone on the human carcinoma cells as has been reported in some experimental findings (Das et al. 2019).

13.6.7 Antifungal Activity

A. calamus rhizome crude methanol extract shows strong antimicrobial action on numerous microorganisms including filamentous fungi, yeasts and bacteria. These crude methanolic extracts of rhizome of A.calamus exhibited high activity against filamentous fungi like Trichophyton rubrum, Microsporum gypseum and Penicillium marneffei, average action against yeast particularly Cryptococcus neoformans, Saccharomyces cerevisiae and Candida albicans, and less action against bacteria (Phongpaichit et al. 2005). Kumar (2014) reported that the antimicrobial activity of Acorus calamus is due to the presence of flavonoids, glycosides, saponins, resins and steroids in its rhizome.

Rhizome and leaf ethyl acetate extracts exhibited pronounced antifungal activity as well as anti-yeast activity. Further, bothα- and β-Asarones possesses a strong antimicrobial property against the yeasts as well as fungi than leaf and rhizome extracts (Devi and Ganjewala 2009). The ethanolic crude extract of rhizome of A. calamus, Tinospora cordifolia and Celestrus paniculatus showed anti-fungal activity against Alternaria solani, Curvularia lunata, Fusarium sp., Bipolaris sp. and Helminthosporium sp. at different concentrations. It also possesses antioxidant, antibacterial and anti-inflammatory property as well. (Singh et al. 2010). Dhiman et al. (2018) studied the effect of A. calamus extract on fungal growth on wooden samples of Pinus roxburghii and Bombax ceiba at different concentrations and found that wood samples treated with A. calamus L. extract were able to inhibit the fungal growth significantly. Dethoupa et al. (2019) studied the efficacy of A. calamus crude ethanol extract against eight plant pathogenic fungi: Alternaria brassicicola, Colletotrichum capsici, Bipolaris oryzae, Lasiodiplodia theobromae, Phytophthora palmivora, Pyriculariaoryzae, Rhizoctonia solani and Sclerotium rolfsii and reported that that extract had significant antifungal activity both in vitro and under greenhouse conditions against B. oryzae in rice. β-Asarone and galangin were found to be the major antifungal compounds active against the tested plant pathogenic fungi. Thus A. calamus L. extract is a promising candidate as a botanical fungicide to control brown spot of rice.

13.6.8 Antioxidant and Radical-Scavenging Activity

Rhizome extract shows strong superoxide anion-scavenging activity and with the increase in the concentration of phenolic content of the rhizome, the antioxidant activity is also increased, however, the leaf extract possesses striking radical-scavenging activity and ferric reducing antioxidant power as well (Devi and Ganjewala 2011). The antioxidant effects may be because the rhizome concentrate has enough quantity of ascorbic acid and polyphenolic compounds in it. These compounds are having potential for enhancing antioxidant potential and function in the brain and that may be because of the presence of α-asarone, an anti-oxidant compound present in the rhizome (Rawat et al. 2016).

13.6.9 Phytoremediation Potential

Phytoremediation is a new cheap and eco-friendly technique that uses plants to clean the environmental pollution by heavy metals. The aquatic plant A. calamus was tested for its ability to accumulate Sb from contaminated water in laboratory experiments. The results showed that A. calamus serves as a good candidate for phytoremediation of water contaminated with Sb (Sytar et al. 2016).

13.6.10 Neurotransmission

A. calamus rhizome extract results in suppression of enzyme, acetylcholinesterase due to the presence of an active component β-asarone, hence aids in cholinergic neurotransmission (Feng et al. 2015).

13.6.11 Anti-depressant Activity

A. calamus methanolic extract, when was given to rats under experimental conditions for a period of 7 days manifested dose-dependent anti-depressant activity with a potential similar to 5 mg/kg imipramine (Chellian et al. 2018; Pawar et al. 2011). However, aqueous extract of rhizomatous portion of the plant causes sedative effects on cardiovascular tissue under in vitro conditions that is 55–60% lowering in heart beat rate and atrium contractile force (Shah and Gilani 2012).

13.6.12 Increases Memory Power

Oral ingestion of few milligrams of active component, β-Asarone for approximately a month helps in preserving of perception in rats with a vigor in comparison to donepezil hydrochloride, which is associated with lowering of hippocampal cell death rate (Geng et al. 2010; Zhou et al. 2016).

13.6.13 Blood Pressure Regulation

Rhizome extracts helps in lowering the enhanced systolic and diastolic blood pressure. It also aids in decreasing the plasma renin as well as oxidative bio markers particularly glutathione in the kidneys (Patel et al. 2012).

13.6.14 Anti-helminthic Activity

Rhizomes of A. calamus also possesses anti-helminthic activity particularly against earthworms (Merekar et al. 2011). Bhakta et al. (2013) studied the anti-helmintic potential of crude methanolic, ethanolic and aqueous extracts of the leaves of Acorus calamus on Indian earth-worm (Pheretima posthuma). The activity involved the determination of time of paralysis (vermifuge) and time of death (vermicidal) of the worm and reported that all the extracts exhibited significant anti-helmintic activity at a concentration of 100 mg/ml, however, peak activity was exhibited by the methanolic extract at a concentration of 100 mg/ml. Calamus’s essential oil possesses anticholinesterase effects (Mathew and Subramanian 2014) and antidiabetic potential (Rau et al. 2006) as well.

13.7 Conclusions

Acorus calamus L. is an endangered, rhizomatous or tuberous herb, found in marshy tracts of Kashmir, locally known as Vai-gander. A. calamus based cottage industry has been found to be the fifth major constituent of household income employment in one of the districts of Kashmir valley. It is locally used for the treatment of various kinds of ailments. Besides it is used as anti-depressant, increases memory power, used in neurotransmission also regulates blood pressure, possesses anthelmintic, anti-bacterial, antifungal properties. There is higher degree of genetic divergence within the individuals of the population of A. calamus from Kashmir. Amplified RAPD and cpSSR fragments were found specific for them while these fragments were found completely absent in populations collected from other states of India. The populations of A. calamus from the Kashmir region of India need more focus in the conservation programs, as these populations are genetically distinct, and possess low concentration of carcinogenic β-asarone in their essential oil. A. calamus from the Kashmir region of Union territory Jammu and Kashmir, India has excellent potentials for the commercial cultivation. The moderate gene flow in the populations of A. calamus can be regarded as a useful feature for the preservation of the genetic distinctiveness of the populations from Kashmir (Ginwal et al. 2011).