Adenosma (PROSEA)
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Introduction |
Adenosma R.Br.
- Protologue: Prodr.: 442 (1810).
- Family: Scrophulariaceae
- Chromosome number: x= unknown;A. indiana:n= 36
Origin and geographic distribution
Adenosma comprises about 15 species and is distributed in tropical Asia and Australia. In Indo-China, 9 species have been found, in Thailand 7 species. Approximately 5 species occur in Malesia, of which A. caerulea , A. indiana and A. javanica (Blume) Koord. are the most widespread.
Uses
In Malaysia, a decoction of Adenosma roots has been used internally to treat bowel complaints and rheumatism. In Vietnam, the flowering tops are applied as a diuretic, diaphoretic and cholagogue, as a tonic and alterative for women after childbirth, and to treat fever, jaundice, viral hepatitis, oliguria, ophthalmia, vertigo and dyspepsia. Extracts and decoctions of A. caerulea are commonly used in Vietnam; they are considered to have powerful antibacterial, cholagogue, diuretic and stomachic effects. In China, A. caerulea is applied to treat rheumatoid arthritis and skin diseases, and A. indiana to treat fever, headache, dyspepsia, gastroenteritis and skin inflammations. The latter species is also used to make a potion to soothe the body. It is also applied as insecticide; it is put in bundles in rooms or spread on beds. The plants are also put on the body for perfume and decoration.
A. bracteosa Bonati is also considered a valuable medicinal plant in Indo-China.
Properties
Plants are fragrant, both in fresh and dry condition, due to the presence of an essential oil (up to 1%). More than 35 constituents have been identified in the essential oil from the aerial parts of Vietnamese A. caerulea , the major constituents being α-pinene (about 23%), 1,8-cineol (18%) and γ-terpinene (17%). L-fenchone was the main component of the essential oil of A. indiana (about 34%); other compounds include L-limonene (23%) and α-humulene (12%). In essential oil from Vietnamese A. bracteosa thymol (about 26%) was the major component, followed by linalool (13%) and (E)-β-farnesene (10%); however, a different chemotype of A. bracteosa has also been found, which contains 1,8-cineole, carvacrol (34%), methyl carvacrol (19%) and β-bisabolene (17%).
Studies in Vietnam showed that Adenosma drugs are non-toxic; they display antibacterial and antiphlogistic activity and increase bile secretion. Extracts of A. caerulea and A. indiana showed marked anti-inflammatory activity in tests on laboratory animals. Treatment of patients suffering from hepatitis showed positive results.
Botany
Annual or perennial herbs, often aromatic. Leaves opposite, simple, serrate, petiolate or subsessile; stipules absent. Inflorescence axillary and terminal, head-like or spike-like. Flowers bisexual, with 2 bracteoles at base of calyx; calyx irregularly 5-lobed; corolla with cylindrical tube, bilabiate, upper lip entire to emarginate, lower lip 3-lobed; stamens 4, included, didynamous, adnate to halfway the corolla tube; ovary superior, 2-locular, style filiform, stigma 2-lobed. Fruit a capsule, dehiscent with 4 valves, many-seeded. Seeds small, with reticulate testa.
Ecology
Adenosma is found in open forest and forest edges, grassland, rainfed rice fields and along watercourses, up to 1300 m altitude.
Management In Vietnam, A. caerulea is cultivated for medicinal purposes; it is propagated by seed. When seedlings attain a height of 15-20 cm, they are transplanted in the field at a planting distance of about 20 cm. They should be kept free of weeds and top-dressed with manure. The plants can be harvested 3.5-4 months after planting. The yield is 2.5-3 t/ha of air-dry material.
In some areas of China, A. indiana is intercropped with upland rice. It is planted together with the rice at the beginning of the rainy season, but in different planting holes. It is harvested 1-2 months after rice harvesting.
Plants are usually collected at the flowering stage. The whole plant except for the root is gathered. Plants are dried in the shade; overheating should be avoided.
Genetic resources
The Adenosma species treated here are widely distributed and occur commonly in disturbed vegetation. This makes them in general unlikely to be at risk of genetic erosion. However, up to 100 t of dry A. caerulea plant material is collected annually from the wild in Vietnam, and this has led to a decline in population size. For this reason, the species has started to be cultivated in recent years.
Prospects
The Adenosma species in Malesia seem to be poorly known and little used. However, elsewhere in mainland South-East Asia they are popular medicinal plants. They contain pharmacologically interesting compounds, particularly in the essential oil, and seem to have potential as insecticide as well.
Literature
250, 673, 741.
Selection of species
Authors
Nguyen Tap & Nguyen Kim Bich
