Inula helenium (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Inula helenium L.

Protologue: Sp. pl. 2: 881 (1753).

Family: Compositae

Chromosome number: 2n= 20

Synonyms

• Aster helenium (L.) Scop. (1772).

Vernacular names

• Elecampane, elfdock, yellow starwort (En).
• Grande aunée, inule, œil de cheval (Fr)
• Vietnam: thổ mộc hương.

Origin and geographic distribution

I. helenium is a native of Central Asia, but is naturalized widely in northern Europe, the United States, China and Japan, and on a small scale in Indo-China. It is occasionally cultivated.

Uses

The root oil of I. helenium is used in China, Japan, Indo-China, and Peninsular Malaysia as a diuretic, diaphoretic, expectorant and a tonic. In the United States and the United Kingdom, the roots are used as a diuretic and an emmenagogue. It has a warming, salty flavour. It is applied in treating skin and chest diseases such as coughs, colds, asthma, oedema, tuberculosis and eczema. In the past, it was used in Europe in a similar way. In Vietnam and Peninsular Malaysia the root and flower heads of I. helenium are imported from China, and are found in Chinese pharmacies.

In China and Japan, the root ("Helenii radix") is also considered vermifugal and germicidal, and may be taken to treat cholera, malaria, inflammation of the intestines, dysentery, and bronchitis. It is used externally against snake and insect bites. In Korea, the root is used to treat ear- and toothache.

I. helenium was cultivated in Europe as a root vegetable in ancient times; nowadays it is still sometimes candied and used to flavour alcoholic beverages, sweets and desserts. The leaves are used for seasoning salads, and also yield a blue dye. It is cultivated in Europe and eastern Asia as an ornamental with large flower heads.

Production and international trade

I. helenium used to be cultivated on a large scale for its medicinal roots in southern Russia and in Europe, and on a smaller scale in eastern Asia. This trade is no longer very important, but the large area of distribution resulting from former cultivation indicates that it must have been of considerable importance in the past. The dried roots and dried flower heads are traded locally on markets in Central and eastern Asia and in Japan.

Properties

As is the case with many Compositae, the aromatic and bitter tasting roots of I. helenium contain inulin (40-45%), a polysaccharide consisting of D-fructose residues. Triterpenes (e.g. dammaranedienol acetate) and sterols (sitosterol, stigmasterol) have also been found.

Upon steam distillation, I. helenium yields a 1-3% crystalline mass, with a little oil. This mass consists of sesquiterpene lactones, mainly the eudesmanolides alantolactone (52.4%), isoalantolactone (33%), dihydroalantolactone, their 11,13-dihydro derivatives and related compounds. The mixture is also known as helenin (in older literature) or inula camphor, although these names are also applied to alantolactone itself.

The root extract and the volatile fraction exert a number of pharmacological effects, which are mainly caused by alantolactone and isoalantolactone. They exhibit significant activity against the Gram-positive bacteria Staphylococcus aureus and Streptococcus pyogenes, and significant activity against Mycobacterium tuberculosis. The compounds also show in vitro antifungal activity against Microsporum cookei, Trichophyton mentagrophytes and Trichothecium roseum. Other activities include antiprotozoal activity against Entamoeba histolytica and Trichomonas vaginalis, and anthelminthic activity against Meloidogyne incognita. Guinea-pigs infected with the nematode Trichinella spiralis, which causes trichinelliasis, were treated with helenin to test its effect on the intestinal stages. Those receiving 100 mg/kg helenin daily for 30 days had about 7.5% fewer muscle larvae than their controls; those receiving 300 mg/kg for 10 days had about 62.5% fewer larvae and those given a single, toxic dose of 2500 mg/kg had about 77% fewer larvae. The effect might be caused by nematode muscular activity combined with the stimulation of intestinal peristalsis in the host. The constituents of helenin also have excellent antifeedant properties against phytophagous pests, and are toxic to the mosquito Aedes atropalpus. They show allelopathic action against the weeds Amaranthus retroflexus L. and Chenopodium strictum Roth, but also improve root formation in Vigna radiata (L.) Wilczek. A lymphocyte transformation test used in vivo and in vitro in mice showed that alantolactone had significant allergenic capacity. Boiled water extracts of I. helenium were screened for clonorchicidal activity in rabbits infected with the worm Clonorchis sinensis. The extract disclosed significant regressive and progressive changes, such as degeneration, atrophy, necrosis and dilatation of viscera of the worms. The cytostatic action of a 40% ethanol extract of I. helenium herbs on cultured human lymphoblastoid cells was studied and was found to suppress cell growth completely at 50-200μg/ml. I. helenium flowers contain the flavonoids quercetin, quercetin-7-triglucoside and 3-methylquercetin.

Description

• An erect, robust, tomentose perennial, 60-150(-250) cm tall, with a thick root base, short rhizome-like roots, and forked stems in the upper part.
• Leaves alternate, simple, lower leaves ovate to elliptical, 40-70 cm × 10-25 cm, base rounded, apex acuminate, margins dentate, upper leaves smaller, base cordate, shortly pubescent above, grey-tomentose underneath; lower leaves long petiolate, upper leaves sessile, amplexicaul; stipules absent.
• Inflorescence a terminal or axillary hemispherical head, solitary or few together, 2.5-7 cm in diameter (large in cultivars), involucral bracts many-seriate, outer bracts ovate, 10-13 mm × 4-5 mm, tomentose, inner bracts smaller, lanceolate, receptacle flat or slightly convex, without scales.
• Ligulate flowers female, many, corolla 30-40 mm long, 3-toothed at apex, much exceeding the involucre, curled upwards, bright yellow, tubular flowers bisexual, many, corolla 5-toothed, yellow; stamens 5, anthers sagittate; ovary inferior; style bifurcate.
• Fruit an oblong, striped achene, 3-5 mm long, glabrous; pappus hairs about 30, 5-8 mm long, free.
• Seedling with epigeal germination.

Other botanical information

Inula belongs to the tribe Inuleae and is a little known genus of which the number of species is estimated between 40-90, occurring in the warm and tropical regions of the Old World. The centres of diversity are in Central Asia and in southern Europe, where about 18-25 species are found. None of the species are found in the wild in Malesia, but some occur in Indo-China.

I. brittannica L. (synonym I. japonica Thunb.), a widespread, originally European species, is cultivated in China and Japan. The flower heads are found in the Chinese pharmacies in Peninsular Malaysia and have similar uses to I. helenium.

Ecology

I. helenium prefers moist, sunny to half-shady locations, and is found along forest roads, but also in humid pastures and orchards, from sea-level up to 1400 m altitude.

Propagation and planting

I. helenium is propagated by seed or root cuttings. Germination of 1-year-old seeds is between 93-97% in Moldavia, but reduces to 50% after 4 years. In the Ukraine, seed of I. helenium is sown either in autumn (untreated) or in spring (after 1-1.5 months stratification).

Husbandry

Best root harvests of I. helenium are obtained from 3-year-old plants grown from seeds or 2-year-old plants from root cuttings. In Indo-China, I. helenium is still cultivated for medicinal or ornamental purposes.

Diseases and pests

Capitophorus vandergooti, Cassida murraea and Lygus rugulipennis are common insect pests on cultivated I. helenium in Russia. The insecticide fosfamid (dimethoate) applied at 1.2 kg/ha gives 70-100% control of sucking insects such as thrips, and leaves no residues in the roots. The nematode genera Aphelenchoides, Aphelenchus, Cephalobus and Panagrolaimus are commonly found on the roots of I. helenium.

Harvesting

In China, the open flower heads are collected during July-October. Roots are harvested in autumn.

Yield

The fresh root weight of juvenile, mature and senescent plants of different populations of I. helenium in Russia is very variable, being 3-40, 73-343 and 64-303 g/plant respectively.

Handling after harvest

The flower heads and roots of I. helenium are dried in the sun before being stored.

Genetic resources and breeding

Small germplasm collections of I. helenium are present in Germany, Poland, Portugal, Russia and Canada. There are no known breeding programmes.

Prospects

Although I. helenium does not occur naturally in Malesia, it has the potential to be cultivated in areas with a sub-humid climate. Its sesquiterpene lactones show interesting pharmacological activities. However, in view of the risks of allergies, their therapeutic use should be limited. Upon further investigation, they might serve as templates in research.

Literature

• Alonso, B.N., Fraginals, R., Lepoittevin, J.P. & Benezra, C., 1992. A murine in vitro model of allergic contact dermatitis to sesquiterpeneα-methylene-γ-butyrolactones. Archives for Dermatological Research 284(5): 297-302.
• Boatto, G., Pintore, G., Palomba, M., de Simone, F., Ramundo, E. & Iodice, C., 1994. Composition and antibacterial activity of Inula helenium and Rosmarinum officinalis essential oils. Fitoterapia 65(3): 279-280.
• Bradley, P.R. (Editor), 1992. British herbal compendium, Volume 1. The British Herbal Medicine Association, Bournemouth, Dorset, United Kingdom. pp. 87-88.
• Kiselev, V.P. & Kondratenko, B.S., 1976. Biological characteristics and productivity of elecampane introduced in the Moscow region and Ukrain SSR. Resursy Dikorastushchikh Lekarstvennykh Rastenii USSR 3: 213-220. (in Russian)
• Leshchankina, V.V., 1981. Age composition, productivity and raw material resources of some Inula helenium populations in Mordovia. Rastitel’nye Resursy 17(3): 367-372. (in Russian)
• Rhee, J.K., Baek, B.K. & Ahn, B.Z., 1985. Structural investigation on the effects of the herbs on Clonorchis sinensis in rabbits. American Journal of Chinese Medicine 13(1-4): 119-125.

Other selected sources

• [14] Adilova, N.B., 1970. Nematode fauna of some wild medicinal plants in the Samarkand district (Agalyk) of the Samarkand region (USSR). Uzbekskii Biologicheskii Zhurnal 14(3): 44—46. (in Russian)
• [125] Bourrel, C., Vilarem, G. & Perineau, F., 1993. Chemical analysis, bacteriostatic and fungistatic properties of the essential oil of elecampane (Inula helenium L.). Journal of Essential Oil Research 5(4): 411—417.
• [130] Bruneton, J., 1995. Pharmacognosy, phytochemistry, medicinal plants. Technique & Documentation Lavoisier, Paris, France. 915 pp.
• [131] Bubium, Z. & Wartenberg, L., 1965. An attempt to use helenine in the treatment of experimental trichinelliasis in guinea pigs. Zeszyty Naukowe Wyzszej Szkoly Rolniczej we Wroclawiu 63: 131—139. (in Polish)
• [135] Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A—H) pp. 1—1240, Vol. 2 (I—Z) pp. 1241—2444.
• [146] Cantrell, C.L., Abate, L., Fronczek, F.R., Franzblau, S.G., Quijano, L. & Fischer, N.H., 1999. Antimycobacterial eudesmanolides from Inula helenium and Rudbeckia subtomentosa. Planta Medica 65(4): 351—355.
• [309] Flora Europaea (various editors), 1964—1980. Volume 1—5. Cambridge University Press, Cambridge, United Kingdom.
• [401] Hegi, G., 1918. Illustrierte flora von Mittel-Europa [Illustrated flora of Central Europe]. Vol. VI-I, Scrophulariaceae-Compositae (part). Verlag J.F. Lehmanns, München, Germany. 544 pp.
• [564] Kowalewska, K. & Lutomski, J., 1978. Flavonoids in Inula helenium inflorescences. Herba Polonica 24(3): 107—113. (in Polish)
• [675] Milman, I.A., 1990. Alanto- and isoalantolactones. Chemistry of Natural Compounds 26(3): 251—262.
• [739] Nguyen Van Duong, 1993. Medicinal plants of Vietnam, Cambodia and Laos. Mekong Printing, Santa Ana, California, United States. 528 pp.
• [750] Ohwi, J., 1965. Flora of Japan. Smithsonian Institution, Washington D.C., United States. 1067 pp.
• [786] Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. 620 pp.
• [957] Spiridonov, N.A. & Arkhipov, V.V., 1994. Cytostatic action of medicinal plants on cultured lymphoblasts. Khimiko Farmatsevticheskii Zhurnal 28(9): 49—51. (in Russian)

Authors

• Wongsatit Chuakul, Noppamas Soonthornchareonnon, Orawan Ruangsomboon