Ammannia baccifera (PROSEA)
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Introduction |
- Protologue: Sp. pl. 1: 120 (1753).
- Family: Lythraceae
- Chromosome number: n= 12
Vernacular names
- Blistering ammannia (En)
- Philippines: bias-pugo (Tagalog), apoy-apoyan (Pangasinan, Tagalog), parapit-angit (Pampangan)
- Thailand: kaeo raknaa (Ratchaburi), mafai nok khum (Bangkok), yaa raknaa (northern)
- Vietnam: mùI chó.
Origin and geographic distribution
A. baccifera has a very large distribution comprising Africa, Afghanistan, Pakistan, India, Sri Lanka, Indo-China, China, Thailand, throughout Malesia (except Borneo, as far as is known) and Australia; recently introduced into the Caribbean (Guadeloupe, Jamaica).
Uses
In the Philippines, A. baccifera is used in place of cantharides as a blistering plaster. In Pakistan and India, bruised fresh leaves are used for raising blisters against rheumatic pains and fever. A. auriculata Willd. is used for similar purposes. The leaves or the ash of A. baccifera , mixed with oil, are applied externally to cure herpetic eruptions and other skin diseases, and as remedy for ringworm and parasitic skin affections. An infusion made from entire plants is claimed to have aphrodisiac activity.
Properties
A. baccifera is intensely acrid. Food contaminated with the leaf extract may produce severe burning pain in the abdomen. Betulinic acid, daucosterol, ellagic acid, n-hentricontane, lupeol, quercetin and triacontane-1,30-diol have been found in chemical studies.
Tests with rats showed anti-urolithic activity for an ethanolic extract of A. baccifera . A dose of 2 g/kg/day of the extract was effective in reducing the formation of urinary stones as well as in dissolving pre-formed ones. An aqueous ethanol extract showed hypotensive activity in dogs and mice. Extracts showed antibacterial activity against several plant pathogenic and human pathogenic bacteria; extracts obtained from stems, leaves and inflorescences were more effective than those from roots and seeds.
A compound with strong piscicidal activity, α-naphthoquinone, was isolated from A. baccifera . Leaves are used to reduce sexual libido in animals.
Botany
An erect, annual or short-lived perennial herb up to 100 cm tall, glabrous, much-branched. Leaves decussately opposite, lanceolate to oblanceolate, 1-5(-7) cm × 0.5-1(-1.5) cm, usually attenuate at base, acute to subobtuse at apex, entire, glabrous, subsessile; stipules absent. Inflorescence an axillary, dense, more or less sessile cyme. Flowers sessile or subsessile, 4(-5)-merous, with 2 small bracteoles at base; hypanthium persistent in fruit; sepals inserted on the hypanthium, persistent in fruit; petals absent; stamens inserted on the hypanthium, equal in length; ovary superior, style absent or very short, stigma capitate. Fruit a globose capsule, 1-1.5(-2) mm in diameter, slightly exceeding the hypanthium, irregularly circumscissile, many-seeded. Seeds obovoid, concave-convex, up to 0.5 mm long.
Seeds may remain viable for many years. They float in water due to their convex-concave shape and by a large aerenchymatous float on the concave side. Under conditions of high humidity, light intensity and temperature, germination may start within one week, with the majority of seeds germinating in two weeks.
Ammannia consists of about 25 species and is cosmopolitan, with the greatest diversity in Africa (16 species). It is often difficult to identify specimens: they appear to be intermediate between the accepted species. A possible reason for this may be that the plants are predominantly autogamous, but with at least a low level of outcrossing. Apparently they sometimes hybridize. Ammannia is related to Rotala and Nesaea , which differ in the fruits having dense transverse striations and opening with 2-5 septicidal valves in Rotala and dehiscing first by a small apical operculum and then irregularly in Nesaea . A. baccifera is a variable species.
Ecology
A. baccifera occurs in wet locations, very often as a weed in rice fields in the lowland, up to 1200 m altitude. Like other Ammannia species, it can be a problematic weed in rice fields.
Management Maximum alkaloid synthesis was found in plants at the fruiting stage, under moderate light intensity and with a photoperiod of 16 hours. The application of NPK-fertilizer enhanced the alkaloid content. For controlling A. baccifera as a weed of rice, 1 kg/ha of oxadiazon has been applied successfully in India, and in Taiwan bensulfuron-methyl showed good results at 0.5 kg/ha. High rates of 2,4-D are recommended in Indonesia. The chrysomelid beetle Altica cyanea was found feeding on A. baccifera in rice fields in India, defoliating the plants completely, but no damage to the rice crop was observed. Apparently the beetle may be a biological control agent.
Genetic resources
Efforts are being directed towards eradication of A. baccifera as a noxious weed of rice, and not towards protection.
Prospects
Some interesting properties of A. baccifera deserve more attention, particularly the antibacterial activity, the anti-urolithic activity, and the reputed effectiveness against skin diseases.
Literature
289, 470, 752, 760, 879.
Other selected sources
121, 394, 593, 666.
Main genus page
Authors
R.H.M.J. Lemmens
