1218

12(2): Medicinal and poisonous plants 2

Pangium edule Reinw.

Sylloge Plant. Ratisb. 2:: 13 (1825).

FLACOURTIACEAE

2n = unknown

Pangium rumphii Voigt (1845), Hydnocarpus polyandra Blanco (1845), Pangium ceramense Teijsm. & Binnend. ex Boerl. (1899).

Indonesia: picung (Sundanese), pucung (Javanese), pangi. Malaysia: kepayang, payang. Papua New Guinea: puga (Agenehembo, Oro Province), ola (Bayer river, Western Highlands Province). Philippines: pangi (Samar-Leyte Bisaya, Panay Bisaya, Bikol), salingkumut (Mandaya).

Pangium edule is found throughout Malesia, from the Philippines, Malaysia, Indonesia to Papua New Guinea, and extending eastward to the Bismarck Archipelago, the New Hebrides and Micronesia; small-scale cultivation is found throughout its natural range.

Most of the medicinal and poisonous applications of Pangium edule are based on the presence of hydrocyanic acid in all parts of the plant, ranging from seeds, fruits, leaves, bark or roots. Fresh leaves, leaf sap, pounded leaves or ground fresh seeds are externally applied as an antiseptic and disinfectant to cleanse ulcerations, infested wounds, and to treat scurf. Likewise they can be used as an insecticide against head lice and ticks and as an insect repellent in general.
Fresh leaves can be used to preserve meat or game for several days. The freshness of the meat is retained and insects are repelled. Mention is made of meat already infested with maggots being rendered palatable as a result of the leaves killing the maggots. The ground immature seeds, more precisely the kernels, can be used to preserve fish for several days. The ground kernels are either applied in layers alternating with the freshly caught fish, or the intestines of fish are removed and replaced by the ground kernels. The ground kernels can be removed before preparing the fish for consumption. The pounded bark or immature seeds can be used as a fish poison, whereas pounded leaves are used to stupefy shrimp. The difference is apparently a matter of dosage of the hydrocyanic acid. In the Philippines, all parts are considered an efficient anthelmintic. In Papua New Guinea the fruit is sliced and the juice applied to sores and cuts. All parts are sometimes credited with narcotic properties, an overdose resulting in sleepiness, headache and a sort of intoxication or attack of delirium, which may result in death. These effects may result from the consumption of inadequately prepared seeds. The poisonous agent can be deactivated by extensive washing, soaking, roasting or fermenting. The oil extracted from fresh or cooked kernels can be used as a good substitute for coconut oil in cooking; application for illumination or soap making is also possible but in general the oil is considered of poor quality for these applications. For medicinal use cold pressed oil is preferred, as this still contains hydrocyanic acid. The seed oil is the most important preservative used in traditional weaving of the Iban in Borneo. After an elaborate preparation the mature seeds are sold as 'kluwak', a condiment for 'bumbu rawon', an Indonesian mixture of spices and condiments and as an ingredient of 'sayur kluwak'. The sapwood and heartwood is yellow, with a disagreeable odour, rather hard, but not very durable, used occasionally for local construction and suitable for match sticks.

Although statistics on international trade are not available for Pangium edule, local economic importance is evident. Mature 'processed' seeds are for sale as 'kluwak' in markets throughout Indonesia, in particular in Java or in regions with many Javanese or Sundanese migrants, at a price of about US$ 1/kg.

All parts of Pangium edule contain a high percentage of gynocardine, a cyanogenic glycoside of the unsaturated alicyclic aglycone type. For example upon crushing or damaging (e.g. by insects) the plant material, the enzyme gynocardase is liberated, which catalyzes the hydrolysis of gynocardine in its sugar (glucose) and aglycone (a cyanohydrin) part. Subsequently, the very unstable cyanohydrin decomposes, and liberates toxic hydrocyanic acid. The hydrocyanic acid thus can be responsible for a range of biological activities, including antibacterial, antifungal, and insecticidal effects.
Gynocardine can be easily eliminated from fresh or dried plant material by sufficient washing or heating (the latter destroys the enzyme gynocardase).

Cyanogenic glycosides are found throughout the plant kingdom, in at least 70 families. Perhaps the best known tropical species in this respect is cassava root (Manihot esculenta Crantz (Euphorbiaceae), which may contain up to 0.4% of the cyanogenic glycoside linimarin.

A dioecious, more rarely andromonoecious, medium-sized tree, up to 40 m tall, with a dense crown and drooping branches; trunk up to 1 m in diameter, buttresses present. Leaves spirally arranged, simple, ovate-cordate, (10—)12—30(—60) cm x 8—20(—40) cm, entire, 5—7-veined from the base, dark green, glabrous, shining above, dull beneath; petiole 7—30(—50) cm long; stipules absent. Flowers usually unisexual, but the terminal flowers of the male inflorescence sometimes bisexual, rather fragrant; male flowers in few-flowered pseudo-racemes, 6—24 cm long, including 5—12 cm long peduncle, pedicel 2.5—4 cm long, female flowers mostly solitary in the axils of the upper leaves, pedicel 6—9(—12) cm long; calyx closed before anthesis, nearly globose, disrupted irregularly in 2—3(—4) segments, lobes reflexed about 1(—2) cm long, petals (4—)5—8(—9), imbricate, ovate-oblong, 1.5—2.5 cm, somewhat fleshy, bright pale green; male flowers with 20—25(—31) stamens, 0.8—1.3 cm long, free; female flower with as many staminodes as petals and alternating with them, rarely 20—25, ovary superior, ovoid, sessile, with 2—4 many-ovuled placentas, stigma sessile. Fruit an indehiscent, asymmetrical oblong to ovoid drupe, 15—25(—30) cm x 7.5—12(—15) cm, bluntly to distinctly sharp tipped at both ends, brownish, rather scurfy and rough, hanging from a curved stalk, containing about (13—)20(—40) irregularly shaped closely packed, interlocked seeds, pericarp coriaceous, 0.5—1 cm thick, becoming soft an mushy in the ripe fruit. Seed almost triangular, (3—)4—6 cm x 2—3(—4) cm, enclosed by a white oily and fleshy, sweet, aromatic, edible aril, greyish white when fresh, blackish when weathered, leathery. Seedling with epigeal or hypogeal germination; cotyledons emergent or non-emergent; hypocotyl elongated; all leaves arranged spirally, conduplicate.

In a seedling trial of Pangium edule in Malaysia 9 out of 14 non-scarified seeds germinated after 20—32 days; germination resembles that of durian (Durio zibethinus Murray). Saplings can maintain themselves in the forest. Trees usually start fruiting from about 15 years, but occasionally a tree may start fruiting at 6 years. Trees can be found flowering throughout the year, fruiting appears to be concentrated at the beginning of the rainy season. Flowering starts immediately after every new flush of leaves. Fruiting can happen 1—4 times a year, with smaller fruits during massive fruiting. The development of the trees accords with Aubréville's model, so-called 'pagoda trees' or 'Terminalia branching': growth is determined by a monopodial trunk with rhythmic growth, bearing whorled branch tiers, and branching plagiotropic by apposition. Leaves are crowded at the end of branches. The biggest leaf in each cluster is thrust out on the underside, and the other leaves are placed to overshadow it as little as possible. The seed of Pangium edule can float for a long time and can thus be distributed by rivers and sea currents.

Pangium is a monotypic genus, that was formerly included in the family Bixaceae. In Sarawak, considerable variation in fruits and seeds has been observed. The typical form is called 'kepayang lenga', and fits most descriptions so far published. The fruits are oblong to oblong-oval, 18—23 cm x 10—14 cm, tips almost rounded, blunt, about 0.5 cm long; about 25—30 seeds per fruit; seed 3.5—4.0(—6.0) cm long. A second form is called 'kepayang papan'. The fruits are subglobular to ellipsoidal, 16—24 cm x 11—16 cm, tips oblong-triangular, sharp, 1.5—2 cm long; about (13—)20—24(—19) seeds per fruit: seed 3.5—5.5 cm long. A third form is called 'kepayang bubur'. The fruits are ellipsoidal to oval, 18—20 cm x 12—14 cm, tips almost rounded, blunt, about 0,5 cm long; 25—30(—40) seeds per fruit; seed 2.5—3.0(—4.0) cm long.

Pangium edule is found in primary rain forest and secondary forest, in many regions chiefly in deforested localities, always as isolated specimens though locally common, wild or semi-cultivated, also along river banks, in teak forest, on both dryland and temporarily inundated places, on stony or clayey soils, chiefly below 300 m altitude but sometimes up to 1000 m altitude.

In view of the hard seed coat of Pangium edule, scarification followed by immersion in water for 24 hours prior to sowing is preferred. A seed bed consisting of sand facilitates transplanting. Germination takes about 1 month, seedlings are transplanted to individual pots when 2—3 leaves have developed. Potting medium consists of equal amounts of compost and sand. After 4 months the seedlings can be transplanted to the garden.

Pangium edule does not appear to suffer from serious diseases or pests.

Fruits are in general not harvested until they have fallen from the tree. To obtain the seeds the fruits are often left rotting for 10—14 days as this facilitates removal of the seeds.

Fruits on average weigh 1 kg, but may weigh up to 2.5 kg. A mature tree yields approximately 300 fruits a year. An annual production per tree of about 250 kg processed seeds seems feasible.

For fish preservation the seed coat of Pangium edule is removed and the kernels are finely cut and dried in the sun for 2—3 days. Seeds for cooing oil extraction are generally cooked for several hours. The seed coat is removed and the kernels are put in running water for 24 hours, or directly dried in the sun. Following this the oil is extracted by pressing.

Pangium edule is widespread and common throughout Malesia, semi-cultivated in some areas and therefore not endangered. Locally natural regeneration may be hampered by overexploitation. There are no known breeding programmes of Pangium edule.

Knowledge of the numerous uses of Pangium edule has become rare. Very little information is available on the pharmacological properties of extracts and purified compounds from Pangium edule. More research is needed to evaluate its potential. The tree is a true multi-purpose species that deserves to be promoted in view of its potential as a natural pesticide and food preservative in remote areas in the absence of electricity.

Faridah-Hanum, I., 1996. Morphological variation of Pangium edule Reinw. fruits in Malaysia. The Gardens= Bulletin Singapore 48(1—2): 189—194.
Heyne, K., 1950. De nuttige planten van Indonesië [The useful plants of Indonesia]. 3rd Edition. Vol. 1. W. van Hoeve, 's-Gravenhage, the Netherlands/Bandung, Indonesia. pp. 1135—1138.
Partomihardjo, T. & Rugayah, 1989. Pangi (Pangium edule Reinw.) dan potensinya yang mulai dilupakan [Pangi (Pangium edule Reinw.) an almost forgotten plant and its potential]. Media Konservasi 2(2): 45—50.
Perry, L.M., 1980. Medicinal plants of East and Southeast Asia. Attributed properties and uses. MIT Press, Cambridge, Massachusetts, United States & London, United Kingdom. p. 156.
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Roemantyo & Ervizal A.M. Zuhud

Roemantyo & Zuhud, E.A.M., 2001. Pangium edule Reinw.. In: van Valkenburg, J.L.C.H. and Bunyapraphatsara, N. (Editors): Plant Resources of South-East Asia No 12(2): Medicinal and poisonous plants 2. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea