Scaevola taccada (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Scaevola taccada (Gaertner) Roxb.

Protologue: Fl. ind. 2:146 (1824)

Family: Goodeniaceae

Chromosome number: 2n= 16

Scaevola taccada (Gaertner) Roxb. - 1, flowering and fruiting branch; 2, flower; 3, fruit

Synonyms

• Lobelia taccada Gaertner (1788),
• Scaevola sericea Vahl (1791),
• Scaevola frutescens Krause (1912).

Vernacular names

• Sea lettuce tree (En)
• Indonesia: dudulan (Javanese), babakoan (Sundanese), subong-subong (Bengkulu)
• Malaysia: ambong-ambong, buas-buas laut, akar pahit
• Papua New Guinea: gavagava (Milne Bay), pahop (Manus Island)
• Philippines: boto, mosboron (Tagalog, Bisaya), bosboron (Tagalog, Bikol, Bisaya)
• Thailand: bong bong, rak thale (peninsular), ho raa (south-eastern)
• Vietnam: hếp, sơn dương.

Origin and geographic distribution

S. taccada is found from Madagascar eastward to South-East Asia, throughout Malesia, tropical Australia, the Pacific Islands and Hawaii. It is cultivated and sparingly naturalized in the south-eastern United States.

Uses

Throughout South-East Asia and Australia, diluted sap from the leaves or sap from the ripe berries of S. taccada is used in folk medicine to clear opacity of the eye and in the treatment of eye infections. In Malaysia, the bitter leaves may be eaten as a cure for indigestion, and the leaves may be used as a poultice for headache. In Indonesia, the root is applied as an antidote after eating poisonous fish or crab. In the Philippines, the roots in decoction are used in beri-beri and in certain syphilitic affections, also in dysentery. In Thailand, roots and leaves are used for skin affections.In Finschafen (Papua New Guinea), the young leaves are chewed and boiled into a tea or else the juice from the heated leaves is mixed with water to treat cough. The sap may be directly applied to sores. Likewise, young leaves are chewed to soothe a cough on New Hanover Island, and to treat tuberculosis on Karkar Island. After removal of the epidermal layer the leaf is chewed to treat malaria. Similarly, on several islands north of New Guinea, the leaves are used to treat cough or colds. In New Ireland and Milne Bay, an extract from the leaves is used as a form of long-term contraception by women. Other applications include the treatment of earache in Manus Island, and asthma and tuberculosis in Karkar Island. In northern Australia the juice squeezed from young stems and ripe fruits is applied directly to bites and stings. In Samoa, the leaves are traditionally used for skin ailments, swellings, elephantiasis, scrotal swellings, oedema, chill and indigestion; the roots are considered a good therapy for cancer; the bark is applied for abscesses, menstrual complaints and bone fractures; the stem is used for abdominal complaints. In the Western Highlands in Papua New Guinea juice from the stems of S. oppositifolia R.Br. is applied to ear inflammations. In other parts of New Guinea, stem sap is further used to cleanse a sore eye and on wounds, and when hot on topical ulcers.

Throughout Malesia, the wood from the base of the mature stems of S. taccada is used as nails in traditional boat building. In the Philippines, its leaves are occasionally smoked like tobacco. Apart from its ornamental value S. taccada is used for soil stabilization and wind and salt spray protection in coastal zones.

Production and international trade

S. taccada is only used on a local scale.

Properties

A general phytochemical screening of the leaves, bark and flowers of S. taccada gave no positive tests for alkaloids. Leaves were positive for saponins, as well as coumarins. In the literature, there is occasional mention of the presence of an alkaloid scaevolin.

Furthermore, in an in vitro assay, an acetonitrile extract of the leaves showed selective antiviral activity against herpes simplex virus 1 and 2 and vesicular stomatitis virus.

Description

• An erect spreading shrub or small tree up to 4(-7) m tall; branchlets terete.
• Leaves alternate, the majority crowded at the end of the branches, spathulate to obovate, 12-26 cm × 5-10 cm, base attenuate, apex blunt to rounded, margin entire, sinuate to dentate, herbaceous to thin-fleshy, glabrous to shortly tomentose, sessile; stipules absent.
• Inflorescence axillary, cymose, laxly branched, about 4 cm long, few-flowered, bracts persistent, peduncle 0.5-2 cm long.
• Flowers 5-merous, zygomorphic, 2-2.5 cm long, scentless, white to pale yellow, pedicel 0.3-1.2 cm long, glabrous to densely appressed hairy; calyx adnate to the ovary, lobes linear to narrowly elliptical, 0.2-0.5 cm long, persistent; corolla glabrous to pubescent outside, densely pubescent inside, tube 0.5-1 cm long, lobes membranous, fimbriate towards the base, about 0.5 cm long; ovary inferior, 2-celled, style faintly pubescent at base.
• Fruit a fleshy drupe, 1-1.5 cm in diameter, faintly 2-lobed and ribbed, pellucid-white when ripe, stone 0.8 cm × 0.6 cm, 2-seeded.
• Seedling with epigeal germination; cotyledons emergent, fleshy; hypocotyl elongated.

Growth and development

Flowers of S. taccada are protandrous, thereby enhancing cross pollination. They are frequently visited by bees and wasps. The fruits are dispersed by frugivorous birds and sea-currents. The fruits are buoyant because of a corky outer layer and no significant loss in viability is observed after 250 days in sea water. S. taccada flowers and fruits throughout the year.

Other botanical information

Scaevola has a pantropical distribution and comprises about 100 species, most of them endemic to Australia. The genus is divided in 3 sections. The vast majority of species belong to section Xerocarpa that is almost exclusive to Australia. Section Enantiophyllum is confined to eastern Malesia and northern Australia, represented by S. oppositifolia. Confusion is rampant concerning the nomenclature of the strand Scaevola species, both belonging to section Scaevola. The widespread variable species are at present classified as 2 species, S. plumieri (L.) Vahl with an Indo-Atlantic distribution and S. taccada with an Indo-Pacific distribution. They are primarily distinguished by the incision of the calyx and the colour of the fruit.

Ecology

S. taccada is a typical constituent of the Barringtonia formation. It is usually confined to the seashore, restricted to sandy beaches or rock and coral outcrops, occasionally found inland on Pacific atolls in sunny disturbed habitats and rock faces. It is capable of substantial growth and physiological responses, which are required in coastal habitats characterized by large temporal and spatial variations in substrate salinity and salt spray levels. Seaward expansion is limited by a combination of salt spray and substrate salinity.

Propagation and planting

S. taccada can be propagated by seed or cuttings. The stone should be removed from the pulp before planting. After rubbing and washing, stones can be dried for storage. Stones are preferably soaked in cool water for 24 hours and covered lightly by soil in a well-drained potting mix. Germination may take up to 3(-9) months. Germination is enhanced by soaking in sea water, speeding up the process by 1-2 weeks. Cuttings can be up to 50 cm long, with the lower leaves removed, and the upper ones cut in half. Planting should be in a light well-drained potting mix or a sandy soil, with watering once a day. Rooting should be achieved in 2-3 months. Air layering is another option for propagation.

Diseases and pests

In Florida, ornamental S. taccada plants are affected by ringspot disease caused by a strain of the cucumber mosaic virus.

Harvesting

Fruits of S. taccada are collected when ripe, all plants parts are simply collected whenever the need arises.

Genetic resources and breeding

S. taccada is widespread and common in coastal habitats throughout South-East Asia, and therefore not endangered.

Prospects

Very little is known about the phytochemistry and phytopharmacology of S. taccada . More research will be needed to fully evaluate its possible medicinal potential.

Literature

• Alpha, C.G., Drake, D.R. & Goldstein, G., 1996. Morphological and physiological responses of Scaevola sericea (Goodeniaceae) seedlings to salt spray and substrate salinity. American Journal of Botany 83(1): 86-92.
• Carolin, R.C., 1992. Scaevola. In: George, A.S. (Editor): Flora of Australia. Vol. 35. Brunoniaceae, Goodeniaceae. Australian Government Publishing Service, Canberra, Australia. pp. 84-146.
• Leenhouts, P.W., 1957. Goodeniaceae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Series 1, Vol. 5(3). Noordhoff-Kolff N.V., Djakarta, Indonesia. pp. 335-344.
• Locher, C.P., Burch, M.T., Mower, H.F., Berestecky, J., Davis, H., Van Poel, B., Lasure, A., Van den Berghe, D.A. & Vlietinck, A.J., 1995. Anti-microbial activity and anti-complement activity of extracts obtained from selected Hawaiian medicinal plants. Journal of Ethnopharmacology 49(1): 23-32.
• Shannon, R.K., Wagner, W.L. & Nicolson, D.H., 1997. Proposal to conserve the name Scaevola taccada (Goodeniaceae) with a conserved type. Taxon 46: 801-802.
• Woodley, E. (Editor), 1991. Medicinal plants of Papua New Guinea. Part 1: Morobe Province. Wau Ecology Institute handbook No 11. Verlag Josef Margraf, Weikersheim, Germany. pp. 65-66.

Other selected sources

• [135] Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. Revised reprint. 2 volumes. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A—H) pp. 1—1240, Vol. 2 (I—Z) pp. 1241—2444.
• [143] Cambie, R.C. & Ash, J., 1994. Fijian medicinal plants. Commonwealth Scientific and Industrial Research Organisation, Canberra, Australia. 350 pp.
• [148] Carolin, R.C., 1990. Nomenclatural notes, new taxa and the systematic arrangement in the genus Scaevola (Goodeniaceae) including synonyms. Telopea 3(4): 477—516.
• [258] Dittmar, A. 1998. Zur traditionellen Heilkunde Samoas. Charakteristika und Strukturierungen des Heilpflanzenuniversums [Traditional medicine in Samoa. Characteristic and classification of medicinal plants]. Dissertation University of Frankfurt. Verlag Dr. Hänsel-Hohenhausen, Egelsbach, Frankfurt, München, Germany. 470 pp.
• [350] Goldstein, G., Drake, D.R., Alpha, C., Melcher, P., Heraux, J. & Azocar, A., 1996. Growth and photosynthetic responses of Scaevola sericea, a Hawaiian coastal shrub, to substrate salinity and salt spray. International Journal of Plant Sciences 157(2): 171—179.
• [407] Heyne, K., 1950. De nuttige planten van Indonesië [The useful plants of Indonesia]. 3rd Edition. 2 volumes. W. van Hoeve, 's-Gravenhage, the Netherlands/Bandung, Indonesia. 1660 + CCXLI pp.
• [418] Holdsworth, D.K., 1977. Medicinal plants of Papua New Guinea. Technical Paper No 175. South Pacific Commission, Noumea, New Caledonia. 123 pp.
• [730] Ng, F.S.P., 1991—1992. Manual of forest fruits, seeds and seedlings. 2 volumes. Malayan Forest Record No 34. Forest Research Institute Malaysia, Kepong, Malaysia. 997 pp.
• [786] Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. 620 pp.
• [810] Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. 1262 pp.
• [1075] Wohlrabe, K. & Hansel, R., 1977. Cumarine aus Scaevola frutescens [Coumarins from Scaevola frutescens]. Archiv der Pharmazie (Weinheim) 310(12): 972—974.
• [1077] Wong, K.M., 1993. Two new species of Scaevola (Goodeniaceae) endemic to Borneo. Sandakania 3: 11—16.

Authors

• Trimurti Hesti Wardini