Alternanthera (PROSEA)

From PlantUse English
Jump to: navigation, search
Logo PROSEA.png
Plant Resources of South-East Asia
Introduction
List of species


Alternanthera Forssk.

Protologue: Fl. aegypt.-arab.: 28, lix (1775).
Family: Amaranthaceae
Chromosome number: x= unknown; A. ficoidea:n= 34, A. philoxeroides: 2n= 28, 100, A. sessilis:n= 17, 18, 20, 2n= 34, 96

Major species

  • Alternanthera sessilis (L.) DC.

Origin and geographic distribution

Alternanthera comprises approximately 150 species and is distributed in all tropical and subtropical regions, but the New World tropics are by far richest in species. Seven species have been found in Malesia, only one of which (A. sessilis) is indigenous; the other species have been introduced and are often locally naturalized.

Uses

An infusion of the entire plant of A. sessilis is used in Indonesia as a remedy against intestinal cramps, diarrhoea and dysentery, and externally as a cooling agent to treat fever. In Malaysia it is used internally against intestinal inflammation and fever, and externally to treat wounds. A. sessilis is used in local medicine in Taiwan, often in mixtures with other medicinal plants such as Eclipta prostrata (L.) L., Hypericum ascyron L. and Wollastonia chinensis (Osbeck) Merr., to treat hepatitis, tight chest, bronchitis, asthma and lung troubles, to stop bleeding and as a hair tonic. It is used locally in Thailand and India against dysentery, as cholagogue, abortifacient and febrifuge, and to treat snake bites, inflamed wounds and boils, and in Thailand and Sri Lanka as a galactagogue. An extract from A. philoxeroides is used medicinally in India to treat "female diseases". A. pungens is reported in India to be useful as diuretic and to treat gonorrhoea.

The densely matted growth of some species (e.g. A. ficoidea) makes them useful for protecting soil against erosion. A. philoxeroides can be used as a tertiary filtration system for domestic sewage. Several species are planted in gardens as ornamentals. Some Alternanthera species are valued for aquarium decoration. Cooked leaves of A. sessilis are sometimes eaten as vegetable.

Production and international trade

Dried plants of Alternanthera are only occasionally traded on local markets and by herbalists. They are not traded on the international market.

Properties

Little is known about the chemical constituents of the various Althernanthera species. A C-glycosylated flavonoid, alternanthin, has been isolated from A. philoxeroides. The triterpenes α-spinasterol and β-spinasterol have been demonstrated to occur in several Alternanthera species, among which A. sessilis. This species is also reported to contain stigmasterol, β-sitosterol, oleanotic acid and its derivatives, and saturated (aliphatic) esters. A high iron content (about 2%) has been found in A. philoxeroides.

A. sessilis leaves contain 12 g/100 g dietary fibre. Incorporation of about 75 g of this vegetable fibre in the daily diet of diabetics, significantly reduced the postprandial blood glucose level. The leaves of A. sessilis are rich in β-carotene.

In tests in India, leaf pastes of A. sessilis exhibited inhibition of mutagenicity in Salmonella typhimurium strains. They inhibited the formation of the potent environmental carcinogen nitrosodiethanolamine from its precursors such as triethanolamine. The aqueous alcohol extract of the entire plant exhibits hypothermic and histaminergic activities and relaxes smooth muscles. An ether extract of A. sessilis yielded an active principle having anti-ulcerative properties.

An aqueous extract of A. philoxeroides inhibited the growth of the human immunodeficiency virus (HIV-1) in vitro at concentrations non-toxic to the host cells (H9 cells, human T-helper lymphocytes). It was also inhibitory to the growth of the herpes simplex (HSV) and respiratory syncytial viruses (RSV). The infectivity of extracellular virions of HIV-1, HSV and RSV was partially destroyed by the extract, but no activity on extracellular virions, or on virus growth was found for vesicular stomatitis virus (VSV), adenovirus (AV) or polio virus (PV). Chemical studies have indicated that the active anti-HIV-1 component was heat-stable, water-soluble and non-dialysable. Preliminary chemical characterization revealed that it might be a partially sulphonated polysaccharide.

A. philoxeroides extracts can markedly protect suckling mice from being infected by epidemic haemorrhagic fever virus (EHFV). After the infected mice were treated, their survival rate increased and pathological lesions and virus antigen in the tissues mitigated as compared with the controls. However, therapeutical doses caused slight deformations of the hepatic cells. Preliminary chemical investigations revealed that the active component might be a coumarin analogue.

Extracts prepared (leaves, cold water) from A. brasiliana and A. ficoidea showed antiviral activity against herpes simplex (HSV-1) virus in HEp-2 cells in vitro at non-toxic concentrations. The activity is however, influenced by the process of extracting. Using hot water or a lyophilization procedure might drastically decrease the activity. Crude aqueous extracts of A. brasiliana and A. ficoidea also showed antiviral activity against Aujeszky disease virus (ADV) in IB-RS-2 pig cell cultures, and bovine diarrhoea virus (BVD) in GBK bovine cell lines. The antiviral activity might vary depending on the temperature used during extraction.

Antiviral activity against tobacco mosaic virus in beans and tobacco has also been demonstrated for several Alternanthera species.

Description

  • Annual or perennial herbs, erect, ascending, creeping, clambering or floating, often much branched, often hairy with dentate or smooth hairs.
  • Leaves opposite, simple and entire, with short petiole; stipules absent.
  • Inflorescence an axillary or rarely terminal head, sessile or stalked, sometimes a short spike.
  • Flowers bisexual, solitary in axils of bracts, subtended by 2 scarious bracteoles; perianth often dorsally compressed, with 5 free, equal or unequal tepals; stamens 2-5, sometimes some without anthers, filaments united at the base into a short cup or longer tube, usually alternating with staminodes, anthers small, 1-celled; ovary superior, 1-celled, often compressed, style short with capitate stigma.
  • Fruit an indehiscent utricle, sometimes corky, 1-seeded, falling off with the perianth and with or without bracteoles.
  • Seed variably lenticular.
  • Seedling with epigeal germination; cotyledons leafy, glabrous, apex rounded; hypocotyl and epicotyl elongated, purplish.

Growth and development

A. philoxeroides is a C3 plant. Each stem node is capable of producing a new plant under favourable conditions.

The dark brown, corky fruits of A. sessilis often float in great quantities on the water. Some of the introduced species (A. ficoidea, A. philoxeroides) do not set fruit in Malesia.

Other botanical information

Alternanthera is closely related to Gomphrena, which differs particularly in the shape of the androecium.

There is much confusion about the correct name for the taxon which is dealt with here under the name A. ficoidea. In 1989 the Committee for Spermatophyta of the International Association for Plant Taxonomy recommended maintaining the much used name A. ficoidea for this species, even though it is nomenclaturally incorrect (the correct name is A. tenella), in order to stabilize the nomenclature. A. ficoidea cultivated in South-East Asia should be considered as a cultigen of the South American species.

Ecology

Alternanthera species are usually found in moist localities. A. sessilis prefers open places such as roadsides, gardens and along rice fields, but A. brasiliana shows a preference for shaded localities (e.g. on slopes). A. philoxeroides can tolerate a large range of habitats, growing out over water as dense floating mats or on moist soil as individual plants. Plants of this species can grow at NaCl concentrations of 400 mol/m3. A. pungens is adapted to more dry locations.

Several species are noxious weeds, e.g. A. sessilis in upland rice, carrot and tomato, A. philoxeroides in irrigated rice and A. brasiliana in coffee. A. ficoidea is a dreaded weed in beans, soyabeans, groundnuts, plums and cotton in America.

The leaves of some Alternanthera (e.g. A. sessilis) can be purplish pigmented by the occurrence of anthocyanins and betalains. An inverse correlation has been observed between pigmentation intensity and soil moisture.

Propagation and planting

A. ficoidea and A. philoxeroides do not produce ripe seeds in Malesia. However, A. ficoidea can easily be propagated from cuttings or divisions, whereas A. philoxeroides can rapidly develop new plants from stem parts. A. sessilis can probably also be propagated very easily from seed and vegetatively.

In vitro production of active compounds

Cell suspension cultures of A. philoxeroides have been derived from leaf callus grown at 25 °C in the dark in Murashige and Skoog medium containing 1 mg/ml 2,4-D. After an abrupt and substantial increase in salinity, the suspension cells exhibited a rapid attainment of water balance and cell growth. Concomitant with the ability of these cultures to withstand an increase in NaCl are the abilities to produce betaine and to take up exogenous betaine.

Husbandry

In general, Alternanthera can stand pruning well.

Diseases and pests

A leaf spot disease of A. sessilis caused by Fusarium pallidoroseum has been described in Nigeria. It may spread to crops in which A. sessilis occurs as a weed, e.g. okra, yams, potatoes, onions and carrots.

Introduction of the lepidopterous Vogtia malloi from Argentina and the alligator weed flea beetle (Agasicles hygrophila) from the United States into several countries has successfully reduced populations of the noxious aquatic weed A. philoxeroides.

Genetic resources and breeding

Alternanthera species are not endangered. On the contrary, they are often noxious weeds expanding their area of distribution (e.g. A. philoxeroides in Australia). However, the genetic variability of the species originally introduced in South-East Asia is rather small because of the limited number of introductions and the vegetative mode of reproduction. It is unclear whether the medicinal properties attributed to these introduced species apply to the present South-East Asian populations as well.

Prospects

Some of the medicinal properties of Alternanthera warrant further research. The antiviral effects of A. philoxeroides, and the anti-ulcerative properties of A. sessilis seem to be the most promising.

Literature

  • Backer, C.A., 1949. Amaranthaceae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Series 1, Vol. 4. Noordhoff-Kolff N.V., Djakarta, Indonesia. pp. 91-94.
  • Council of Scientific and Industrial Research (various editors), 1985. The wealth of India. Revised Edition. Vol. 1. Publications and Information Directorate, New Delhi, India. pp. 206-207.
  • Dharma, A.P., 1981. Indonesische geneeskrachtige planten [Indonesian medicinal plants]. De Driehoek, Amsterdam, the Netherlands. p. 21.
  • Larsen, K., 1989. Caryophyllales. In: Lescot, M. (Editor): Flore du Cambodge, du Laos et du Viêtnam. Vol. 24. Muséum National d'Histoire Naturelle, Paris, France. pp. 46-52.
  • Koseki, I., Simoni, I.C., Nakamura, I.T., Noronha, A.B. & Costa, S.S., 1990. Antiviral activity of plant extracts against aphthovirus, pseudorabies virus and pestivirus in cell cultures. Microbios Letters 44(173): 19-30.
  • Krishnakumar, A., Sivaramakrishnan, V.M. & Sivaswamy, S.N., 1991. Inhibition of nitrosation reaction by some spices/leafy vegetables. Advances in Plant Sciences 4(1): 189-193.
  • Lagrota, M.H.C., Wigg, M.D., Miranda, M.M.F.S., Santos, M.G.M. & Costa, S.S., 1995. Inhibition of herpes simplex virus replication by different extracts of Caryophyllales. Biomedical Letters 51(202): 127-135.
  • Noronha, A.B., Amelia, M., Alexandre, V., De Gaetano, R. & Vicente, M., 1993. Protection against tobacco mosaic virus induced by some Caryophyllales plant extracts. Microbios 73(294): 75-80.
  • Si-man, Z., Yong-sheng, H., Tabba, H.D. & Smith, K.M., 1988. Inhibitor against the human immunodeficiency virus in aqueous extracts of Alternanthera philoxeroides. Chinese Medical Journal 101: 861--886.
  • Sreedevi & Chaturvedi, A., 1993. Effect of vegetable fibre on post prandial glycemia. Plant Foods for Human Nutrition 44(1): 71-78.

Selection of species

Authors

  • R.H.M.J. Lemmens & S.F.A.J. Horsten