2925

12(3): Medicinal and poisonous plants 3

Swinglea glutinosa (Blanco) Merr.

Journ. Arn. Arb. 8: 131(1927).

RUTACEAE

2n = unknown

Limonia glutinosa Blanco (1837), Aegle glutinosa (Blanco) Merr. (1904), Chaetospermum glutinosum (Blanco) Swingle (1913).

Tabog, swinglea (En). Philippines: tabog, malakabuyau, boyag (Tagalog).

Swinglea glutinosa originates from the Philippines (Luzon). It has been introduced in Central and South America, and in the United States (Florida).

In the Philippines fruit juice of Swinglea glutinosa is a folk remedy for various skin diseases. It is also used as a hair tonic, and rubbed into dog fur to cure itch or to get rid of ticks. The trunk is used in house building, often as a pillar. In Colombia Swinglea glutinosa is cultivated for live fences.

Methanol and methylene chloride extracts of Swinglea glutinosa bark showed promising antiprotozoal activity against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. The cytotoxicity against human promonocytic U-937 cells showed an LD₅₀ value of over 400 µg/ml after 96 h, with a selectivity index well over 10, indicating that the antiprotozoal activity is not based on cytotoxicity. Several acridone alkaloids isolated from the stem bark also showed promising antiplasmodial activity. The one with the highest antiplasmodial activity was, however, still 5 times less active than chloroquine against the chloroquine-resistant Plasmodium falciparum strain, and it showed a high cytotoxicity against HeLa cells.

A small to medium-sized, evergreen tree; twigs angled and pubescent when young, soon becoming terete and glabrous, with 1—2 spines in the leaf axils. Leaves alternate, 3-foliolate; petiole 0.5—5 cm long, very narrowly winged; stipules absent; leaflets cuneate at base, acuminate to rounded at apex, terminal leaflet oblanceolate, 8—12 cm x 3—5 cm, lateral leaflets ovate to obovate, 2.5—5 cm x 1.2—2.5 cm. Flowers solitary or in clusters in leaf axils, sometimes on short twigs leafy at base, bisexual, regular, 5-merous, fragrant, pedicellate; calyx cup-shaped, 2.5—3.5 mm x 1.5—2 mm, with obtuse lobes; petals free, linear, 12—14 mm x 3—3.5 mm, white; stamens 10; ovary superior, short-stalked, obovate, 8—10-celled, pilose, style slender, twice as long as the ovary. Fruit an oblong-ovoid berry 5—10 cm x 3—6 cm, green or yellow, with several seeds in each cell. Seeds woolly, surrounded by glutinous pulp. Seedling with epigeal germination; cotyledons emergent.
Swinglea is monotypic and differs from other Rutaceae genera with hard-shelled fruits (subtribe Balsamocitrinae) in having ellipsoid or ovoid ribbed fruits, with a leathery outer shell showing very long, pointed, radially arranged oil glands in the peel and thick, tissue-containing mucilage glands lining the radial walls of the segments surrounding the seeds.

In the Philippines Swinglea glutinosa is widely distributed at low and medium altitudes, occurring in thickets and in secondary forest. In Central and South America it can be found from sea-level up to 1500 m altitude.

Swinglea glutinosa is usually propagated by seed.

Swinglea glutinosa has been introduced in the tropics of Central and South America as a potential rootstock for Citrus. As such it is represented in regional germplasm collections focusing on tropical fruits as well as germplasm collections in the United States and Spain, specializing in Citrus. Its natural distribution being confined to just a single island makes it potentially vulnerable to genetic erosion. However, its preference for disturbed forest and thickets reduces this risk.

Little is known about the pharmacological activities of Swinglea glutinosa. The provisional results of research on its antimalarial activity deserve further attention.

[760]Quisumbing, E., 1978. Medicinal plants of the Philippines. Katha Publishing Co., Quezon City, the Philippines. 1262 pp.
[987]Weniger, B. et al., 2001. Antiprotozoal activity of Colombian plants. Journal of Ethnopharmacology 78: 193—200.
[988]Weniger, B. et al., 2001. Bioactive acridone alkaloids from Swinglea glutinosa. Journal of Natural Products 64(9): 1221—1223.

[117]Brown, W.H., 1951—1957. Useful plants of the Philippines. Reprint of the 1941—1943 edition. 3 volumes. Technical Bulletin 10. Department of Agriculture and Natural Resources. Bureau of Printing, Manila, the Philippines. Vol. 1 (1951) 590 pp., Vol. 2 (1954) 513 pp., Vol. 3 (1957) 507 pp.
[907]Swingle, W.T. & Reece, P.C., 1967. The botany of Citrus and its wild relatives. In: Reuther, W., Webber, H.J. & Batchelor, L.D. (Editors): The citrus industry. Revised edition. Vol. 1. History, world distribution, botany and varieties. Unive

Gilmour Panggabean

Panggabean, G., 2003. Swinglea glutinosa (Blanco) Merr.. In: Lemmens, R.H.M.J. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(3): Medicinal and poisonous plants 3. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea