Occurrence in North America

1. Occurrence in North America • Originally an Indian plant, Acorus calamus L. has been brought to the US from Europe and can now be found in numerous states. It is a sterile triploid • There is also a mostly Indian tetraploid variety, A. angustatus Bess. • The different varieties can be distinguished e.g. by the composition of their essential oil (see slides below) Map source: www.plants.usda.gov

2. Sweet Flag = Acorus calamus var. americanus (Raf.), or Acorus americanus (Raf.) Raf. is native to the US As hinted by the name „sweet flag“, its rhizomes are edible and used to be candied for consumption. The plant is fertile and diploid Morphological distinction from calamus is possible by leaf vein number and size Sweet Flag Map source: www.plants.usda.gov

3. Taxonomy • Calamus is a basal monocot • Molecular data lead to its removal from Araceae and separation into Acoraceae, the only family in Acorales order (whereas Araceae family is incorporated into Alismatales order) [1] • Chloroplast genome completely sequenced, yet phylogenetic conclusions too ambiguous to help clarify the evolutionary relationships of angiosperms [2] Excerpt from APG II main tree (2003) [1] Chase 2004 [2] Goremykin et al. (2005)

4. Habitat • A semi-aquatic plant, calamus requires moisture for optimal growth • It tolerates both full sun and partial shade • Often it borders on swamps or marshes and riverbeds Image source: www.baumschulen-wehrling.de (upper right), H. Irving in „British wild flowers in their natural haunts“, Ed. A.R. Horwood

5. The rhizomes • Branching, creeping, about 0.5-1.5“ thick, with light brown or pinkish surface • Triangular leaf scars are to be seen on the upper, zigzag-like root scars on the lower side • For medicinal use, the rhizomes are collected either in early spring, or in late fall • Calami rhizoma is monographed in the Swiss and Austrian pharmacopoeias; USP contains fluid extract and infusion monographs Photo: plants grown for the rhizome project (capture June 2009)

6. Compounds accumulated • The rhizomes contain varying amounts of essential oil rich in mono- and sesquiterpenes (example structures) • Dried rhizomes contain some aromatic artefacts (e.g., an isomer of citral) • Clinical trials on rats indicated phenylpropanoid β-asarone to be potentially cancerogenic for mammals • Its content is therefore determined in the course of quality control. It increases with chromosome number. The advantage of the diploid American calamus variety is that it does not produce this compound at all β-asarone acorone acoragermacron sesquiterpenes found in calamus oil

7. Human use • Calamus is a bitter aromatic, its principal therapeutic application is as carminative • Apart from medicinal preparations, the traditional use of calamus rhizomes for culinary purposes (as spice) indicates the ancient knowledge of its wholesome effects • Calamus oil has been a popular component of perfumes for centuries • Because of its cinnamon-like fragrance, calamus has sometimes been used to odorize toothpastes Despite the labeling, the rhizomes and not the roots are used to isolate the volatile oils (by vapour destillation)

8. Human (mis)use • The oil of calamus and the smoke of its rhizomes are reported to possess psychotomimetic and hallucinogenic properties. Legends name it as an ingredient of the witches’ Flying Brew. Fresh rhizomes can be chewed to produce stimulatory effect, similar to coca leaves in South America [1] • Calamus rhizomes (called vacha in Sanskrit or bacch in Hindi) have been employed by Ayurvedic medicine for a variety of indications, such as respiratory diseases, indigestion and gynecological complaints (dys- and amenorrhoea). Its effects are described to include mental rejuvenation, improvement of learning performance and anti-aging potential [2] • It is not cleared, whether the sweet calamus of the Bible is sweet flag or some other herb (Exodus 30:22-25) • Also, “sweet reed” and “sweet rush” are mentioned in their works by Dioscorides and Pliny [3] [1] „Canadian medicinal crops“ E. Small & P.M. Catling (1999), [2] theherbsofayurveda.com/sweetflag.htm [3] Manniche & Forman (1999)

9. In-vitro propagation & transformation • Several organogenesis and micropropagation protocols developed [1,2] • No transformation protocols published for the genus Acorus • Patented method for Agrobacterium-mediated transformation of a plant from Araceae family (Spathiphyllum, EP20060834157) Right: Images from [1]: A-C: shoot proliferation from rhizome tips after 2,4,6 weeks of culture, D: regenerated plant, E: rooted plant, F: acclimatized plant 5 weeks after transplantation [1] Ahmed et al. (2007) [2] Harikrishnan & Hariharan in „Plant tissue culture and biotechnology (Universities Press 1999, Ed. P.B. Kavi Kishor)

10. Current research • Large part of research focuses on the pharmacological/physiological effects of its essential oil and/or constituents thereof. Also, the molecular mechanisms of these effects are being studied • Reports of: • Alleviation of FeCl3-induced epileptogenesis in rats [1] • Anthelmintic activity (oils from several Acorus species and isolated β-asarone [2] • Acetylcholineesterase inhibiting potential [3], potentially via the blockade of calcium channels [4] • Blood-pressure lowering activity [5] • Water extract was found to possess anti-inflammatory effects [6] • An haem-peroxidase isolated from Acorus leaves exhibited antifungal properties in tests with several phytopathogens [7] [1] Hazra et al. 2007 [2] Kumar et al. 2009 [3] Mukherjee et al. 2007, Houghton et al. 2007 [4] Gilani et al. 2006 [5] Shah & Gilani 2009 [6] Kim et al. (2009) [7] Ghosh 2006