338 L. B. MACHADO ET AL. Copyright © 2003 John Wiley & Sons, Ltd. Flavour Fragr. J. 2003; 18: 338–341 FLAVOUR AND FRAGRANCE JOURNAL Flavour Fragr. J. 2003; 18: 338–341 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ffj.1238 Seasonal variation in the composition of the essential oils from the leaves, thin branches and resin of Protium spruceanum (Benth.) Engl. Líbia Bentes Machado, Maria das Graças B. Zoghbi* and Eloisa Helena A. Andrade Departamento de Botânica, Museu Paraense Emílio Goeldi, CP 399, 66040-170 Belém, PA, Brazil Received 26 February 2002 Revised 15 October 2002 Accepted 16 October 2002 ABSTRACT: In a previous paper, we described the essential oils of Protium spruceanum obtained from different parts of the plant. In this paper, the essential oils obtained from the leaves, thin branches and resins were collected from October 1999 at 1 month intervals up to October 2000. At each sampling, the oil content was determined in a Clevenger-type apparatus, and examined by GC–MS. The major component from the leaf, resin and thin branch oils was sabinene (leaves, January 81.4%; thin branches, January 79.8%; resin, October 1999, 61.3%), followed by β -caryophyllene in the leaf oil. The maximum content of β -caryophyllene from the leaf oil was 36.4% in Febru- ary. The highest oil yields were observed from leaves (0.4%) sampled in April and from resin sampled in October 1999 (4.0%). Thin branch oil yields were in the range ≤0.1–0.2%. Copyright © 2003 John Wiley & Sons, Ltd. KEY WORDS: Protium spruceanum; Burseraceae; essential oil composition; sabinene; β -caryophyllene Introduction The Burseraceae is a family of tropical trees and shrubs, especially well represented in South America, the Malay- sian region and Africa. 1 Protium Burm. f. is a genus of approximately 146 species, all but nine neotropical; most are understory trees in primary moist forest on terra firme. The primary centre of diversity is Amazonia, where some 73 species occur, 42 of them endemic to the region. 2 The family Burseraceae is a well-known source of exudates and resins rich in volatile substances that are used for many purposes as well as in the perfumery industry, for the confection of varnish and for other uses. 3 In Amazonia, the indigenous peoples use Burseraceae spp. to light fires, make furniture, prepare medicines and make ink, caulk canoes and boats, volatilize as incense and feed people as well as animals. The fruits of many Amazonian Burseraceae are eaten by guans, toucans, curassows, parrots, brocket deer, capuchin monkeys, spider monkeys, howler monkeys and tortoises, and these species are valued as ‘waiting trees’ for hunting. 4,5 Three paleotropical genera of Burseraceae figure prominently in perfumery—Canarium, Boswellia and Commiphora as sources of ‘elemi oil’ and ‘elemi resinoid’, ‘myrrh oil’ and ‘myrrh resinoids’, ‘olibanum oil’ and ‘olibanum resinoid’ and ‘opopanax oil’ and ‘opopanax resinoid’. 6 These products are used in Oriental-type perfumes for their fragrance and their superior fixative properties 7 and they can be promising substitutes for fixatives of animal origin (Morineau, pers. comm.). The essential oils of most of these species have been used in aromatherapy. 8 Chemical analysis of the essential oils from Protium spp. has led to the identification of terpenoid com- pounds, among which mono- and sesquiterpenes predom- inate. 9–17 The resin oils of Burseraceae spp. are mainly monoterpenes in nature, nevertheless they were different from each other. 11,13,18–20 Gum and oleoresins from Pro- tium spp. are also used to treat many diseases. 21 Protium spruceanum (Benth.) Engl. (syn. Icica spruceana Benth., Protium almececago L. Marchand) is locally known as breu and breu-areu-areu. The resin of P. spruceanum are used to cure stomach ache and to relieve headaches and toothache; the leaves are used to cure fever; and the fruits are eaten by toucans and tortoises. 4 The essential oils of the leaves and thin branches, fruits and resin of P. spruceanum have been analysed previously. 11 In the Amazonian region two seasons are well defined: the rainy season, popularly known as inverno (winter, October– March), and the dry season, called verão (summer, April– September); breu-resin collection is done on a seasonal basis in this region. 22 The aim of the present study was to investigate the variation of the leaf, thin branch and resin oils from P. spruceanum during 1 year of seasonal observation. * Correspondence to: M. G. B. Zoghbi, Departamento de Botânica, Museu Paraense Emílio Goeldi, CP 399, 66040-170 Belém, PA, Brazil. Contract/grant sponsor: Pilot Program to Protect the Rain Forest; Contract/ grant number: PPG-7/World Bank. Contract/grant sponsor: CNP q /PIBIC Program, Brazil.