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18: Plants producing exudates

Myroxylon balsamum (L.) Harms

Leguminosae

Myroxylon pereirae (Royle) Klotzsch, Myroxylon toluiferum Kunth, Toluifera balsamum L.

Tolu balsam (var. balsamum), Peru balsam (var. pereirae) (En).

The native area is northern South America (Colombia, Venezuela, Peru). Introduced and cultivated pantropically, including South-East Asia. Commercially most important in Columbia, El Salvador, Nicaragua and Honduras.

Tolu or Peru balsams are oleoresin exudates obtained from wounded trees. Tolu balsam is a brownish-yellow, plastic solid when fresh, but becomes harder, and eventually brittle, on exposure to air. Peru balsam is a dark brown, very viscous liquid, with a typically 'balsamic' odour, somewhat resembling vanilla. Both balsams are used in perfumery, but only rarely in their natural form; more commonly a prepared oil or 'resinoid' is used. The oil or extract is generally used as a fixative in fragrance applications. There is some use as a flavouring in drinks and sweets, and in incense. Both balsams contain mixtures of cinnamic and benzoic acid esters and these confer some mild antiseptic properties on the balsams, in addition to fragrance properties. Tolu balsam is used as an expectorant and as a flavouring compound in cough mixtures and other pharmaceutical preparations, often in combination with other balsams, although, today, many Tolu syrups described in national pharmacopoeia are synthetic mixtures rather than ones which contain genuine balsam. Peru balsam is used in some pharmaceutical preparations for treating skin disorders. The wood is also useful for timber (like mahogany or cedar) and the tree is also grown as an ornamental or as shade tree.

Tree, up to 40 m tall with a wide spreading crown, trunk up to 1 m in diameter, bark resiniferous. Leaves alternate, imparipinnate, 5—11-foliolate, axis 6—15 cm long; leaflets ovate-oblong, 3—14 cm x 1—7 cm, subcoriaceous, lustrous, with pellucid lines and dots. Inflorescence a raceme; pedicel 1.5 cm long, flowers 1—1.5 cm long, white. Fruit an indehiscent, light brown pod, 6—12 cm x 2—3 cm x 1 cm, style tip noticeably situated below curved upper edge where also the seed is situated, basal portion alate, sterile, 4—7 cm long. Seed 1(—2), reniform, up to 2 cm long, light brown. Myroxylon balsamum grows scattered in forest, preferably with annual rainfall of about 2000 mm and mean annual temperature of 21—28°C. It is subdivided into 3 varieties: var. balsamum (fruit 8—11 cm x 2—3 cm, margins parallel, leaflets glabrous and acuminate; this var. produces the Tolu balsam); var. pereirae (Royle) Harms (fruit 6—9 cm x 1.5—2.5 cm, straight or curved, leaflets smaller than of other varieties; this var. produces the Peru balsam); var. punctatum (Klotzsch) Harms (fruit 8—12 cm x 2.5—3 cm, straight, leaflets abundantly punctate but with very few pellucid lines; this var. produces no balsam). Tolu balsam is harvested by cutting V-shaped notches through the bark and collecting the exuding balsam into cups which are regularly emptied. As many as 20 V-notches are cut in each tree, taking care not to girdle the tree. Peru balsam is harvested differently and there are 2 methods. In the 'cascara' or 'bark' process the bark is scorched for 10 minutes; 8 days later the bark is soft and pieces of about 30—60 cm x 30 cm are cut off at intervals. The remaining bark is crushed and treated with hot water to let the balsam flow, after which the balsam is separated from the water. In the 'panal' or 'trapo' process the trees are beaten on 4 sides, then scorched with a torch to cause the bark to separate from the trunk (some intermediate pieces are left uninjured). After about 1 week the bark drops off and the balsam starts exuding from the wood and is collected in rags that are wrapped around the exposed wood parts; saturated rags are renewed and the balsam is extracted by boiling with water. In the 1940s annual exports of Tolu balsam (mainly from Colombia) and Peru balsam (from El Salvador) were around 80 t and 100 t, respectively. Few recent data are available, but Indian imports of Tolu balsam in the late 1980s/early 1990s were usually about 10 t per year, of which Indonesia, Malaysia, Singapore and Thailand were occasional minor suppliers (assuming this to be genuine Tolu balsam).

[11]Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. 2nd Edition. Ministry of Agriculture and Co-operatives, Kuala Lumpur, Malaysia. Vol. 1 (A–H) pp. 1–1240, Vol. 2 (I–Z) pp. 1241–2444.
[14]Coppen, J.J.W., 1995. Gums, resins and latexes of plant origin. Non-wood forest products 6. Food and Agriculture Organization of the United Nations, Rome, Italy. 142 pp.
[17]Dassanayake, M.D. & Fosberg, F.R. (Editors), 1980–. A revised handbook to the flora of Ceylon. Amerind Publishing Company, New Delhi, India.
[19]Duke, J.A., 1981. Handbook of legumes of world economic importance. Plenum Press, New York, United States and London, United Kingdom. 345 pp.
[23]Heyne, K., 1927. De nuttige planten van Nederlands-Indië [The useful plants of the Dutch East Indies]. 2nd Edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch-Indië. 1953 pp. (3rd Edition, 1950. van Hoeve, 's-Gravenhage, the Netherlands / Bandung, Indonesia. 1660 pp.).
[25]Howes, F.N, 1949. Vegetable gums and resins. Chronica Botanica Company, Waltham, Massachusetts, United States. 188 pp.
[44]Walker, G.T., 1968. Balsam of Peru. Perfumery and Essential Oil Record 59: 705– 707.

E. Boer & P.C.M. Jansen

Boer, E. & Jansen, P.C.M., 2000. Myroxylon balsamum (L.) Harms. In: Boer, E. and Ella, A.B. (Editors): Plant Resources of South-East Asia No 18: Plants producing exudates. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea