Schefflera (PROSEA)

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Plant Resources of South-East Asia
Introduction
List of species


Schefflera J.R. Forster & J.G. Forster

Protologue: Char. gen. pl.: 45, t. 23 (1775).
Family: Araliaceae
Chromosome number: x= 12; S. elliptica: n= 24

Major species

  • Schefflera elliptica (Blume) Harms,
  • S. heptaphylla (L.) Frodin.

Vernacular names

  • Schefflera (En, Fr).

Origin and geographic distribution

Schefflera probably comprises over 400 species and is widely distributed in the tropics and subtropics. In Asia it occurs from Sri Lanka north to the Himalayas and Japan, in Indo-China, Thailand and throughout the Malesian region towards northern Australia, New Zealand and east to Samoa in the Pacific.

Uses

The leaves and bark of several Schefflera species are used as a remedy for cough and as a diuretic and tonic. The leaves show astringent properties and are, for example, given to women after childbirth. A decoction of the leaves of S. elliptica has been proved to be an effective antiscorbutic. The resin has been applied as a vulnerary. In Thailand, an infusion of the leaves is used to relieve asthma.

A great number of other Schefflera species are popular pot plants of considerable economic importance worldwide. In Vietnam, S. leucantha R. Vig. and S. heptaphylla are reported to be cultivated as ornamentals and pot plants. The wood of S. heptaphylla is soft, light and easy to work, and can be used for paper, musical instruments and matchboxes. The leaves and young branches are used as green manure.

Production and international trade

Medicinal products from Schefflera are only used and traded on a local scale.

Properties

Phytochemical investigations have revealed the presence of terpenoid saponins in the leaves and bark of S. heptaphylla. Asiaticoside and its aglycone asiatic acid have been isolated from the bark, together with cauloside D and several new related triterpene saponin glycosides. In general, the glycosides mentioned can be divided into two series of six corresponding ursene and oleanene glycosides, all of which have the same triose moiety in the C-28 position. This is why the names scheffursosides A-F and scheffoleosides A-F have been proposed for these corresponding pairs of glycosides, respectively (asiaticoside = scheffursoside A, cauloside D = scheffoleoside C). From the leaves of S. heptaphylla, 3-epi-betulinic acid and some of its (acetylated) glycosides (3,28-bidesmosidic saponins), oleanonic acid and other closely related triterpene saponins have been isolated. A betulinic acid glycoside has also been isolated from S. elliptica; moreover, its leaves also contain saponins.

Asiaticoside and asiatic acid are known to have several pharmacological effects, mainly involved in wound healing. There are literature reports of stimulation of human fibrinoblast collagen I synthesis (in vitro), just as bacteriostatic actions in tuberculosis models.

An aqueous extract from the leaves of S. elliptica showed bronchodilator activity on the isolated smooth muscle preparation of the respiratory tract of guinea-pigs (constrictions induced by addition of histamine). The effect was similar to other well known bronchodilators such as terbutaline and theophylline (as aminophylline). Therefore, the extract appears promising for the prevention and relief of asthmatic attacks, although the exact nature of the components involved in the action remains to be investigated. Furthermore, a leaf extract of S. elliptica showed a dose-related positive inotropic action on an atria preparation of rats.

Finally, saponins from the leaves of S. leucantha were found to have bronchodilator action.

Adulterations and substitutes

Asiatic acid and asiaticoside have also been reported in extracts of Centella asiatica (L.) Urb., which is a pantropical species extending into some subtropical regions. Asiatic acid has also been found in ether extracts from the wood of Terminalia brassii Exell and T. complanata K. Schumann.

Description

  • Evergreen or deciduous trees, shrubs and woody climbers, often epiphytic; twigs with stellate hairs or glabrous; leaves and bark fragrant when crushed.
  • Leaves arranged spirally, palmately compound, rarely unifoliolate or 2-3 times palmately compound; stipules often elongate, connate and intrapetiolar; leaflets usually entire or occasionally coarsely toothed.
  • Flowers in umbellules or small heads arranged in a panicle or rarely in a raceme or spike, bisexual, actinomorphic; pedicel not articulated; calyx rim-like, undulate or 5-toothed; petals 5 or more, valvate in bud; stamens usually 5, sometimes up to 12 or rarely more; disk epigynous; ovary inferior or half-inferior, 5-12-locular or rarely more, with a single ovule in each cell, styles as many as locules, united or free or absent and then the stigmas sessile.
  • Fruit a smooth or slightly ribbed drupe, fleshy or dry, dark red or black when mature; pyrenes compressed.

Growth and development

Many Schefflera species develop according to the architectural tree model of Leeuwenberg, in which 2 or more orthotropic modules develop below an inflorescence and these are equivalent and determinate by terminal flowering. Development according to the architectural tree model of Tomlinson, which is characterized by the repeated development of equivalent orthotropic modules in the form of basal branches, has been reported for an unidentified Schefflera species. Inflorescences may be terminal or lateral, growth of the modules is usually continuous, sometimes rhythmic. Several species develop strangling roots whereas others are unbranched treelets. Flowers are pollinated by insects.

Other botanical information

Schefflera includes several previously recognized genera, the most important being Agalma, Brassaia, Heptapleurum, Paratropia, Scheffleropsis, Sciadophyllum and Tupidanthus, although some authors still prefer to distinguish some or all of these separately. Schefflera includes several complexes in which species boundaries are still unclear; the Malesian species are in need of a thorough taxonomic revision. In the light of recent taxonomical insight, the species known almost universally since the 1890s as Schefflera octophylla (Lour.) Harms should be called S. heptaphylla (L.) Frodin. It is a renowned medicinal plant from Indo-China, southern China, Taiwan and the Ryukyu Islands.

Ecology

Most medicinal Schefflera are found in the understorey of primary lowland rain forest, occasionally also in secondary forest and thickets. Individual species may be found on limestone hills, and up to 2500 m altitude.

Propagation and planting

Schefflera can be propagated from ripe seed sown under humid conditions. Alternatively, propagation by air-layering, stem and softwood cuttings are common practice for the popular ornamental Schefflera.

Harvesting

In Vietnam, the bark of stem and root of Schefflera are collected all year round, but the best time for harvesting is autumn or just before flowering.

Handling after harvest

The stem bark of Schefflera is scraped off and the root-bark washed to remove the outer layer. The bark is then wrapped for 24-48 hours to develop the aroma as a result of fermentation, and dried in the shade.

Genetic resources and breeding

Schefflera species confined to primary forest habitats and those with limited geographical distribution are potentially threatened by ongoing deforestation in South-East Asia. S. elliptica is widespread and commonly found in a wide range of habitats, including disturbed anthropogenic vegetation, and is less likely threatened.

Prospects

Schefflera 's wound-healing properties and soothing effect on itching skin are probably related to the presence of the triterpenes asiatic acid and asiaticoside. The pharmacological effects of Schefflera triterpenes in general deserve further attention.

Literature

  • Frodin, D.G., 1978. Schefflera. In: Ng, F.S.P. (Editor): Tree flora of Malaya. Vol. 3. Malayan Forest Records No 26. Longman Malaysia Sdn. Berhad, Kuala Lumpur & Petaling Jaya, Malaysia. pp. 25-32.
  • Frodin, D.G., 1986. Studies in Schefflera (Araliaceae), II. Northern Luzon (Philippines) species of the Heptapleurum group. Proceedings of the Academy of Natural Sciences of Philadelphia 138: 403-425.
  • Frodin, D.G., 1990. Studies in Schefflera (Araliaceae), IV. The identity of Vitis heptaphylla L., a long-misplaced Linnaean ivy tree. Botanical Journal of the Linnean Society 104: 309-424.
  • Maeda, C., Ohtani, K., Kasai, R., Yamasaki, K., Nguyen, M.D., Nguyen, T.N. & Nguyen, K.Q., 1994. Oleanane and ursane glycosides from Schefflera octophylla. Phytochemistry 37(4): 1131-1137.
  • Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. pp. 678-681.
  • Satayavivad, J., Bunyapraphatsara, N. & Saivises, R., 1980. Pharmacological and toxicological studies to the constituents of Schefflera venulosa (Araliaceae). In: Department of Chemistry, Faculty of Science, Mahidol University, Bangkok: 4th Asian symposium on medicinal plants and spices (Abstracts). Mahidol University, Bangkok, Thailand. p. 47.
  • Shang, C.B., 1984. Le genre Schefflera (Araliacées) en Chine et en Indochine [The genus Schefflera (Araliaceae) in China and Indo-China]. Candollea 39: 453-486.
  • Taesotikul, T., Panthong, A. & Kanjanapothi, D., 1980. Bronchodilator activity of Schefflera venulosa (family Araliaceae): preliminary investigation. In: Department of Chemistry, Faculty of Science, Mahidol University, Bangkok: 4th Asian symposium on medicinal plants and spices (Abstracts). Mahidol University, Bangkok, Thailand. p. 46.
  • Tomlinson, P.B. & Zimmermann, M.H. (Editors), 1978. Tropical trees as living systems. The proceedings of the fourth Cabot symposium held at Harvard Forest, Petersham, Massachusetts, on April 26-30, 1976. Cambridge University Press, Cambridge, London, New York, Melbourne. pp. 223-231, 269-284.
  • Vu Van Dung et al., 1996. Vietnam forest trees. Agricultural Publishing House, Hanoi, Vietnam. p. 64.

Selection of species

Authors

  • Nguyen Tap & M.S.M. Sosef
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