Other Names: Mangostan, Mangostanier, Semetah
The mangosteen tree is very slow-growing, erect, with a pyramidal crown; grows from 7 to 25 m in height, has dark-brown or nearly black, flaking bark, the inner bark containing much yellow, gummy, bitter latex. The evergreen, opposite, short-stalked leaves are oblong or elliptic, leathery and thick, dark-green, slightly glossy above, yellowish-green and dull beneath 9-25 cm long, 4-10 cm wide, with conspicuous, pale midrib. New leaves are rosy. Flowers, 4-5 cm wide and fleshy, may be male or hermaphrodite on the same tree. The rind of the edible fruit is deep reddish purple when ripe. The fragrant flesh is sweet, creamy and citrusy. The outer shell of the fruit is rather hard, typically 4-6 cm in diameter, and contains insect-repelling substances which discourage insect infestation. The edible flesh inside is shaped like a peeled tangerine but bright white, about 3-5 cm in diameter, nested in a deep red outer pod. Depending on the fruit size and ripeness, there might be seeds in the segments of the white edible part of the fruit. The seeds, however, are not edible unless cooked. The plant does not start producing fruit until around 15 years old.
Mangosteens are usually eaten fresh as dessert. The fruits with the highest number of stigma lobes at the apex have the highest number of fleshy segments and accordingly the fewest seeds.The fleshy segments are sometimes canned, but they lose their delicate flavour in canning, especially if pasteurized for as much as 10 minutes. The more acid fruits are best for preserving. To make jam, in Malaya, seedless segments are boiled with an equal amount of sugar and a few cloves for 15 to 20 minutes and then put into glass jars. In the Philippines, a preserve is made by simply boiling the segments in brown sugar, and the seeds may be included to enrich the flavour.The seeds are sometimes eaten alone after boiling or roasting.
The sliced and dried rind is powdered and administered to overcome dysentery. Made into an ointment, it is applied on eczema and other skin disorders. The rind decoction is taken to relieve diarrhea and cystitis, gonorrhea and gleet and is applied externally as an astringent lotion. A portion of the rind is steeped in water overnight and the infusion given as a remedy for chronic diarrhea in adults and children. Filipinos employ a decoction of the leaves and bark as a febrifuge and to treat thrush, diarrhea, dysentery and urinary disorders. In Malaya, an infusion of the leaves, combined with unripe banana and a little benzoin is applied to the wound of circumcision. A root decoction is taken to regulate menstruation. A bark extract called 'amibiasine', has been marketed for the treatment of amoebic dysentery.
Mangosteen is ultra-tropical and must be grown in consistently warm conditions; exposure to temperatures below 4 °C will generally kill a mature plant. It ordinarily requires high atmospheric humidity and an annual rainfall of at least 120 cm with no long periods of drought. The mangosteen must be sheltered from strong winds and salt spray, as well as saline soil or water.
The tree does best in deep, rich organic soil, especially sandy loam or laterite. In India, the most productive specimens are on clay containing much coarse material and a little silt. Sandy alluvial soils are unsuitable and sand low in humus contributes to low yields. The tree needs good drainage.
Technically, the so-called 'seeds' are not true seeds but adventitious embryos, or hypocotyl tubercles, because there has been no sexual fertilization. When growth begins, a shoot emerges from one end of the seed and a root from the other end. But this root is short-lived and is replaced by roots which develop at the base of the shoot. The process of reproduction being vegetative, there is naturally little variation in the resulting trees and their fruits. Some of the seeds are polyembryonic, producing more than one shoot. The percentage of germination is directly related to the weight of the seed, only plump, fully developed seeds should be chosen for planting. Even these will lose viability in 5 days after removal from the fruit, though they are viable for 3 to 5 weeks in the fruit.