Uvaria (PROSEA)
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Introduction |
Uvaria L.
- Protologue: Sp. pl. 1: 536 (1753); Gen. pl. ed. 5: 240 (1754).
- Family: Annonaceae
- Chromosome number: x= unknown;U. cordata: 2n= 22
Origin and geographic distribution
Uvaria comprises about 100 species and occurs in the tropics of Africa, Asia and Australia, and in New Caledonia. A few dozens of species are found in tropical Asia.
Uses
Uvaria is commonly used in medicine in many parts of its distribution area, including tropical Asia, where usually a decoction of the roots and leaves is applied, especially to treat stomach and intestinal complaints, fever, wounds and skin diseases, and after childbirth. Several Uvaria species are used in traditional medicine in Africa, the most important being U. chamae P. Beauv. and U. afzelii Scott-Elliot, which are used to treat various complaints, often as a febrifuge and to treat wounds and swellings.
The fruits of many species are edible, and the stems are used as a substitute for rattan.
Properties
Alkaloids are present in the bark and, to a lesser extent, in the leaves of U. rufa . Extracts of U. cordata stem bark and leaves showed distinct antibacterial activity but no antifungal properties.
Several cyclohexene oxides have been isolated from U. purpurea stems and leaves. One of these, zeylenone, was found to be a highly active nucleoside transport inhibitor. Uvarigranols, which are polyoxygenated cyclohexenes, have also been isolated from U. purpurea . The acetogenin uvarigrin isolated from its roots showed cytotoxicity against human tumour cell lines. Other acetogenins with in-vitro activity against human leukaemia and colon adenocarcinoma cell lines have been isolated from the Vietnamese U. tonkinensis Finet & Gagnep. A stem extract of the African U. lucida Benth. showed strong mitogenic activity in isolated human and mouse T cells, whereas benzylisoquinoline alkaloids isolated from leaves of the African U. chamae exhibited cytotoxic activity against L929 transformed cells. Extracts of U. chamae and U. klaineana Engl. & Diels, another African species, showed significant antiplasmodial activity.
Hexane and ethyl acetate extracts of root bark of U. narum (Dunal) Wallich and U. hookeri King from India showed substantial antibacterial, antifungal and anthelmintic activities, mainly attributable to acetogenins.
Botany
Lianas, straggling or erect shrubs to small trees; branches often converted into leafy tendrils, usually stellately pubescent. Leaves distichously alternate, simple and entire, often stellately pubescent, pinnately veined, shortly petiolate; stipules absent. Inflorescence a terminal, extra-axillary or leaf-opposed, few-flowered cyme or flowers solitary. Flowers bisexual, 3-merous; pedicel with 2 bracteoles; calyx lobed, irregularly splitting or entire; petals 6(-8), free or shortly connate at base, spreading or recurved; stamens numerous, outer ones sometimes sterile, with connective concealing the anther cells; carpels numerous, free, style absent, stigma horseshoe-shaped. Fruit consisting of several to many stalked monocarps, fleshy, 1–many-seeded. Seeds sometimes with a small aril.
Uvaria belongs to the tribe Uvarieae , as does e.g. Cyathostemma , which differs in its small flowers having petals that do not expand. Uvaria is badly in need of revision.
Ecology
Uvaria most commonly occurs in lowland forest, usually below 1000 m altitude, often in more open localities or edges, also in brushwood or even hedges.
Genetic resources
The Uvaria species treated here are all widespread and do not seem to be in immediate danger of genetic erosion, although they may be rare or even absent in many regions or islands within their areas of distribution.
Prospects
Uvaria species are interesting medicinal plants that deserve more attention in South-East Asia. Important pharmacological properties have been demonstrated, e.g. antimicrobial, anticancer and febrifuge activities, which warrant more research.
Literature
120, 155, 715.
Selection of species
Authors
Max Joseph Herman
