Aidia (PROSEA)
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Introduction |
Aidia Lour.
- Protologue: Fl. cochinch.: 143 (1790).
- Family: Rubiaceae
- Chromosome number: x= unknown;A. racemosa: 2n= 22
Origin and geographic distribution
Aidia comprises approximately 50 species, and is distributed in tropical Africa (about 5 species) and tropical Asia (some species extending to subtropical and temperate regions of China and Japan). In Malesia about 30 species have been found.
Uses
A decoction of Aidia roots has been used to cure bowel complaints, and the bark has reputedly been applied as a febrifuge. The bitter bark of A. cochinchinensis Lour. has been used in Vietnam to treat malaria, and as a purgative against hives (urticaria). The timber is occasionally used for house construction, walking sticks and handles of implements.
Properties
In a screening test with Australian bark and leaf material of A. racemosa no alkaloids were found; a test on in-vitro antitumour properties showed negative results. No further information on properties of Asian species is available, but abundant quantities of the carbohydrate mannitol have been found in root bark of the African species A. micrantha (K. Schumann) Bullock ex F. White and A. ochroleuca (K. Schumann) Petit.
Botany
Small to medium-sized trees, shrubs, lianas or hemi-epiphytes. Leaves opposite, often elliptical, simple and entire; stipules interpetiolar, usually triangular. Inflorescence often appearing leaf-opposed, or pseudo-axillary, pseudo-terminal or from a leafless node, dichasially cymose or cincinnoid, sometimes fasciculate. Flowers bisexual, (4-)5(-9)-merous; calyx toothed; corolla gamopetalous, tube often about as long as or shorter than lobes, pilose inside in upper part, lobes often reflexed; stamens inserted in the upper part of the corolla tube, filaments usually short; ovary inferior, 2-locular, style about as long as the linear to clavate stigma. Fruit berrylike, usually globose, small, often becoming red and ultimately black.
The seeds are probably dispersed by animals; in southern China silver pheasants have been reported to feed on Aidia fruits.
In older literature, species now included in Aidia were considered to belong to the large genus Randia . However, Randia has been split up into numerous smaller genera. There has been much disagreement on the delimitation of Aidia from related genera. In the most restricted sense, only tree species were included in Aidia . Here, a broader view of the genus is followed, including e.g. Anomanthodia and Gynopachis which are lianescent. Further studies are needed to clarify the generic limits of Aidia and related genera.
A. densiflora and A. racemosa have been often confused with each other and with A. cochinchinensis Lour., which is restricted to Vietnam and Hainan. All three species have been confused with Fagraea ( Loganiaceae ).
Ecology
The Aidia species treated here occur in primary as well as secondary forest. Several South-East Asian species are restricted to drier habitats (e.g. coastal and limestone vegetation, kerangas forest).
Genetic resources
A. densiflora and A. racemosa have large areas of distribution and occur in many forest types including secondary forest. Therefore, they do not seem to be liable to genetic erosion.
Prospects
Since too little is known about the properties and biological and pharmacological activities, no judgement can be given on the prospects of the South-East Asian Aidia species.
Literature
121, 731, 791.
Selection of species
Authors
Reza Azmi
