Aglaonema (PROSEA)
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Introduction |
Aglaonema Schott
- Protologue: Wiener Z. Kunst 1829(3): 892 (1829).
- Family: Araceae
- Chromosome number: x= 20;A. commutatum:n= 40, 2n= 120,A. simplex:n= 20
Origin and geographic distribution
Aglaonema consists of approximately 25 species, and is native to tropical Asia from north-eastern India and southern China through the whole of Malesia. About 17 species have been found in Malesia, of which A. simplex is the most widely distributed. Several species are widely cultivated as an ornamental. The first plants were brought under cultivation in Europe at the beginning of the 19th Century.
Uses
Several uses of Aglaonema in traditional medicine have been recorded in South-East Asia. In Malaysia, the roots are used as a tonic for children and as anthelmintic, and a decoction of the roots is drunk to treat fever and dropsy. In the Moluccas, heated leaves are used to reduce swellings, but this sometimes results in sores. A. tenuipes Engl. (synonym: A. siamense Engl.) is used in Laos, Cambodia and Vietnam externally as a poultice for carbuncles, and a decoction of the stem is used as a laxative.
The leaves are reputedly occasionally eaten as a vegetable. Aglaonema species are commonly grown as ornamental plants for their variegated foliage and bright red fruits, e.g. A. commutatum , A. nebulosum , A. simplex , A. nitidum (Jack) Kunth (synonym: A. oblongifolium Schott) and A. crispum (Pitcher & Manda) Nicolson (synonym: A. roebelinii auct.). In tropical regions they are cultivated in gardens, but they are also commonly grown as an indoor pot plant, also in temperate regions.
Properties
A 50% aqueous ethanolic extract of whole A. commutatum plants was found to strongly inhibit the enzyme α-glucosidase. Active compounds were identified as α- and β-homonojirimycin. Glycosidase inhibitors are potentially useful as antidiabetic, antiviral, antimetastatic and immunomodulatory agents. They have shown potential as additional therapeutics for diabetes type 2 and HIV-1 infection. However, although related compounds show antihyperglycaemic effect, intraperitoneal administration of α-homonojirimycin had no effect on blood glucose levels in streptozotocin diabetic mice.
Botany
Herbs with creeping to erect stem, sometimes rooting at nodes, having distinct, smooth and green internodes. Leaves alternate, ovate-elliptical to lanceolate-narrowly elliptical, often unequal at base, often variegated; petiole usually as long as or slightly shorter than leaf-blade, with petiolar sheath. Inflorescence a spadix, 1-9 together, peduncle deflexing in fruit; spathe ovate, green to yellowish-white; spadix cylindrical to clavate, subsessile to stipitate, female zone below, few-flowered, male zone longer. Flowers small, unisexual; male flowers tightly situated, with a single stamen having a more or less distinct filament, anthers opening with 2 apical pores; female flowers with subglobose ovary, 1-locular, 1-ovulate, style short and thick, stigma broad and disk-like. Fruit an ellipsoid berry, red at maturity, 1-seeded. Seed ellipsoid, without endosperm.
A. commutatum is extremely variable. Several botanical varieties and many cultivars have been described. A hybrid origin of this species has been postulated. This is supported by cytological data (plants tetraploid or hexaploid) and by the fact that plants are pollen-sterile and apomictic. The name A. oblongifolium is confusing as it has been used for several species.
Ecology
Aglaonema thrives well in damp and shady localities. Locally it is amongst the dominant species in the undergrowth of the forest, e.g. in Seram where a density of 680 plants/ha has been recorded. In cultivation, they require a porous soil, preferably composed of equal parts of loam, sand, peat and organic matter. When cultivated indoors, plants are often susceptible to low relative humidity, resulting in brown leaf margins.
Management Aglaonema can be easily propagated by terminal or node cuttings of the stem and by divisions of the basal shoot. Tissue culture techniques have also been developed for large-scale propagation as ornamental plants. Several diseases are known to attack cultivated Aglaonema , e.g. leaf spot caused by anthracnose fungi. However, the most serious disease is root rot caused by Pythium splendens .
Genetic resources
Several Aglaonema species are widely cultivated, and breeding activities have resulted in numerous cultivars. However, in the wild, many species are restricted to moist lowland rain forest, a habitat under pressure in many regions. Special attention might therefore be wise to prevent genetic erosion.
Prospects
Aglaonema is well known as an ornamental, but little information is available on the pharmacological value. It is known that glycosidase-inhibiting compounds are present, and this might be of interest for further research.
Literature
53, 407, 671, 678, 684.
Selection of species
Authors
Francisca Murti Setyowati
