Elephantopus (PROSEA)

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Plant Resources of South-East Asia
Introduction

List of species

Elephantopus L.

Protologue: Sp. pl. 2: 814 (1753); Gen. pl. ed. 5: 355 (1754).

Family: Compositae

Chromosome number: x= 11;E. mollis: 2n= 22, 44,E. scaber: 2n= 22,E. spicatus:n= 10, 11, 13, 14, 2n= 22, 26

Major species

Elephantopus mollis Kunth,
E. scaber L.

Vernacular names

Elephant's foot (En).
Pied d'éléphant (Fr)
Indonesia: tapak liman
Malaysia: tutup bumi
Vietnam: cúc chỉ thiên.

Origin and geographic distribution

Elephantopus comprises approximately 30 species and is mainly of tropical American origin. Some species have been introduced in South-East Asia. E. scaber, which is the most widespread in South-East Asia, is possibly indigenous there.

Uses

In South-East Asian countries and India, Elephantopus species are well known in traditional medicine. Their primary use is as a diuretic and febrifuge, but other applications include as an anthelmintic (e.g. filariasis), antibiotic, anti-inflammatory, emollient, diaphoretic, emmenagogue and galactagogue. The plant is known as a remedy for coughs, headache, anaemia, dyspepsia, dysentery, colic pains, diarrhoea and leucorrhoea, and also reported to be beneficial during parturition: to speed birth and expulsion of the placenta, and afterwards to prevent inflammations. These uses are not confined to a certain part of the plant; preparations (such as decoctions or hot water extracts) of the (dried) roots, entire plants or leaves are mentioned in the literature.

Elephantopus preparations are also applied externally to heal wounds (astringent properties are attributed to the plant) and in cases of rheumatism (as a paste made from the entire plant).

In Africa and South America, elephants's foot has similar ethnomedical applications. In Chinese traditional medicine Elephantopus is used to treat influenza, colds, tonsillitis, pharyngitis, conjunctivitis, epidemic encephalitis, hepatitis, cirrhosis, ascites and eczema.

Production and international trade

Elephantopus spp. are commonly collected from the wild, but there is no information on production and trade. A drug derived from E. scaber is available in China as tablets; it is marketed as a Chinese patent medicine.

Properties

Elephantopus plants taste bitter. Most species (e.g. E. mollis and E. scaber) contain elephantopin and/or its related compounds (e.g. molephantin, molephantinin, phantomolin, deoxyelephantopin, isodeoxyelephantopin and 11,13-dihydrodeoxyelephantopin). These elephantopin derivatives (sesquiterpene lactones of the germacrane type, or germacranolides) have been found to be very characteristic of Elephantopus, and have attracted considerable interest because of their reported cytotoxic (anti-cancer) activities.

Molephantin, molephantinin and phantomolin (obtained from the ethanolic extract of E. mollis) have been shown to be active in various tumour assays in vitro (human epidermoid carcinoma of the larynx, human carcinoma of the nasopharynx) and in vivo (Ehrlich ascites carcinoma, Walker 256 carcinosarcoma, Lewis Lung carcinoma, P-388 lymphatic leukaemia). Deoxyelephantopin (from E. scaber) significantly inhibited the growth of Walker 256 carcinosarcoma in rats. Furthermore, dihydroelephantopin inhibited the growth of leukaemia tumour cells, and tomenphantopin-A and -B (from E. tomentosus L.) displayed cytotoxic activity in the in vitro human nasopharynx carcinoma assay. Research has revealed the importance of an α-methylene lactone function for the biological activity of sesquiterpenoid lactones.

Phytochemical investigations for the germacranolides have also revealed the presence of several other compounds. The guaianolides deacylcyanaropicrin, glucoazulanin-C and deacylcyanaropicrin-3β-glucopyranoside (= crepiside E) were isolated from the aqueous fraction of the total ethanolic extract of E. scaber. Stigmasteryl-3β-glucoside (a sterol) was isolated from the chloroform fraction. The triterpenes β-amyrin acetate, lupeol (acetate) and epifriedelanol, and the phytosterol stigmasterol were identified from ethanolic extracts of E. mollis.

Studies on the hepatoprotective effects of water extracts of E. mollis, E. scaber and E. spicatus against acute hepatic damage in rats induced by β-D-galactosamine and paracetamol (acetaminophen) demonstrated that these crude extracts (500 mg/kg intraperitoneally) decrease the levels of serum glutamate-oxalate-transaminase (SGOT) and serum glutamate-pyruvate-transaminase (SGPT). This suggests that treatment with these extracts improves the induced hepatic lesions. In another analogous study, using CCl₄, it was furthermore found that hepatic fatty metamorphosis and necrosis of the central lobules were significantly improved after treatment with E. mollis and E. scaber extracts, but less after treatment with E. spicatus extract.

A preliminary pharmacological evaluation was conducted with aqueous and water/ethanol extracts of E. scaber. Doses of 0.3-6 g/kg induced writhing, loss of muscle tone, ataxia, prostration and death in mice. No analgesic effects of these extracts were detected using the mouse hot-plate (≤30 mg/kg intraperitoneally (i.p.),≤600 mg/kg peroral (p.o.)) or the acetic acid-induced writhing (mouse,≤300 mg/kg p.o.) tests. Both extracts failed to modify diuresis in the rat (≤300 mg/kg p.o.), to reduce carrageenan-induced rat paw oedema (≤600 mg/kg p.o.) or to reduce yeast-induced hyperthermia in rats (≤600 mg/kg p.o.). Aqueous extracts administered at doses of 25-100 mg/kg intravenously reduced blood pressure and heart rate in rats. Absence of diuretic effects was furthermore shown in a placebo controlled trial carried out on 10 healthy human volunteers.

Studies showed that E. scaber exhibits considerable antibacterial activity against the cariogenic bacterium Streptococcus mutans and against Staphylococcus sp. In general, E. scaber markedly inhibits the growth of both gram-positive and gram-negative bacteria. Elephantopus extract exhibits antiviral activity against e.g. polio virus and HIV. Protease and reverse transcriptase inhibition are also reported.

Adulterations and substitutes

Sesquiterpene lactones are common in Compositae, but compounds of the elephantopin type seem characteristic for Elephantopus. In other genera of the tribe Vernonieae, such as Vernonia, the sesquiterpene lactones are mostly of the germacranolide type, and some of these compounds have also shown significant in vitro activity against cells derived from carcinomas (e.g. vernolepin from Vernonia hymenolepis A. Rich.).

Description

Perennial herbs up to 120 cm tall, with a creeping rhizome or strong taproot; stems scabrous or pubescent.
Leaves alternate, often rosulate or basal and cauline, becoming smaller upwards, simple, variously toothed, pinnately veined, cuneately tapering or long-attenuate at base to a winged petiole, exstipulate.
Inflorescence consisting of sessile, few-flowered, homogamous heads aggregated into a globose capitate cluster or glomerule each of which is subtended by 2-4 foliaceous bracts; glomerules in corymbs or panicles or spicately arranged in the axils of small cauline leaves; involucre of head 2-seriate and consisting of about 8 narrowly oblong bracts.
Flowers all tubular, bisexual, 5-merous; pappus of 4-5(-6) scabrid bristles; corolla with unequal, somewhat palmately spreading lobes, white, bluish or purplish; anthers connate and forming a tube around the style, obtuse at base and acute at apex; ovary inferior, 1-celled, style bifid with filiform, hairy arms.
Fruit a truncate, 10-ribbed achene tipped by the 4-5 scabrid pappus bristles, which are dilated at base and equally long or with 2 longer ones sigmoidal at apex.

Growth and development

Elephantopus can be found flowering throughout the year, but there is often a main flowering season (e.g. for E. scaber in Java from April to September). Flowers remain hidden in the involucre until shortly before anthesis. Within a head the usually 4 flowers expand almost simultaneously between 1 and 2 p.m., and close at about 5 p.m. The fruits are often distributed by mammals and people, when the scabrid bristles become caught in the fur or clothes.

Other botanical information

Elephantopus is classified in the tribe Vernonieae, which includes about 70 genera and 1500 species. There is no modern comprehensive review of the tribe and consequently the affinity of Elephantopus is still obscure.

Pseudelephantopus is often kept separate from Elephantopus on the basis of the heads which are clustered in the axils of small cauline leaves and of 2 larger, sigmoid pappus hairs (in Elephantopus s.s. glomerules of heads terminal and usually long-pedunculate, all pappus hairs equal and straight). E. spicatus has been treated here and not separately because some recent publications have again treated Pseudelephantopus as if it is synonymous with Elephantopus (even though it is sometimes considered as a separate subgenus Pseudelephantopus (Rohr) C. Jeffrey). Orthopappus is nowadays also often included in Elephantopus.

Ecology

Elephant's foot usually occurs in waste places, grasslands, roadsides and forest fringes. E. scaber is also found in the undergrowth of teak forest in Java. Elephantopus spp. are usually not noxious weeds, although they may occur on paths in tea plantations, and in lawns, where they are sometimes considered as troublesome. In Hawaii, E. mollis and E. spicatus are classified as noxious weeds, which rapidly invade pastures but have no forage value. In South-East Asia, Elephantopus may occur up to 2000 m altitude.

Diseases and pests

In the Philippines, a mosaic virus may cause mild chlorosis and prominent veins in E. mollis. There are indications that the disease can be transmitted by aphids to coconut and Manila hemp (Musa textilis Née), where symptoms can be more serious.

Harvesting

Elephant's foot is collected from the wild.

Handling after harvest

After collecting, the plants are washed, dried and stored until use. In general, they are collected fresh when needed.

Genetic resources and breeding

Elephantopus spp. are widespread in anthropogenic habitats and seem not to be at risk of genetic erosion. No breeding work has been done to date.

Prospects

Elephant's foot is considered to be an interesting medicinal plant resource with promising prospects for becoming a valuable adjunct in e.g. cancer research or treatment.

Literature

Chen, C.P., Lin, C.C. & Namba, T., 1989. Screening of Taiwanese crude drugs for antibacterial activity against Streptococcus mutans. Journal of Ethnopharmacology 27(3): 285-295.
de Silva, L.B., Herath, W.H.M.W., Jennings, R.C., Mahendran, M. & Wannigama, G.E., 1982. A new sesquiterpene lactone from Elephantopus scaber. Phytochemistry 21(5): 1173-1175.
Hayashi, T., Koyama, J., McPhail, A.T. & Lee, K.-H., 1987. Structure and absolute stereochemistry of tomenphantopin-A and -B, two cytotoxic sesquiterpene lactones from Elephantopus tomentosus. Phytochemistry 26(4): 1065-1068.
Hisham, A., Pieters, L., Claeys, M., Dommisse, R., Vanden Berghe, D. & Vlietinck, A., 1992. Guaianolide glucosides from Elephantopus scaber. Planta Medica 58(5): 474-475.
Jakupovic, J., Jia, Y., Zdero, C., Warning, U., Bohlmann, F. & Jones, S.B., 1987. Germacranolides from Elephantopus spp. Phytochemistry 26(5): 1467-1469.
Lee, K.-H., Ibuka, T., Furukawa, H., Kozuka, M., Wu, R.Y., Hall, I.H. & Huang, H.-C., 1980. Antitumor agents. XXXVIII: Isolation and structural elucidation of novel germacranolides and triterpenes from Elephantopus mollis. Journal of Pharmaceutical Sciences 69(9): 1050-1056.
Lin, C.C., Tsai, C.C. & Yen, M.H., 1995. The evaluation of hepatoprotective effects of Taiwan folk medicine "Teng-Khia-U". Journal of Ethnopharmacology 45(2): 113-123.
Lin, C.C., Yen, M.H. & Chiu, H.F., 1991. The pharmacological and pathological studies on Taiwan folk medicine VI. The effects of Elephantopus scaber ssp. oblanceolata, Elephantopus mollis and Pseudoelephantopus spicatus. American Journal of Chinese Medicine 19(1): 41-50.
McPhail, A.T., Onan, K.D., Lee, K.-H., Ibuka, T., Kozuka, M., Shingu, T. & Huang, H.-C., 1974. Structure and stereochemistry of the epoxide of phantomolin, a novel cytotoxic sesquiterpene lactone from Elephantopus mollis. Tetrahedron Letters 32: 2739-2741.
Poli, A., Nicolau, M., Simoes, C.M.O., Nicolau, R.M.R. & Zanin, M., 1992. Preliminary pharmacologic evaluation of crude whole plant extracts of Elephantopus scaber. Part I: in vivo studies. Journal of Ethnopharmacology 37(1): 71-76.

Selection of species

Authors

Ng Lean Teik