nÃo hà / Este trabalho relata o estudo fitoquÃmico de trÃs espÃcies de plantas da famÃlia Burseraceae: Protium hebetatum Daly (PHB), Protium heptaphyllum (Aublet) Marchand subsp. ulei (Swat) Daly (PHU) e o Protium heptaphyllum (Aublet) Marchand subsp. heptaphyllum (PHH), conhecidas, aleatoriamente, como breu, breu-branco ou almÃcega. As espÃcies foram coletadas no municÃpio de Cruzeiro do Sul, Acre, Brasil. Da resina do PHB, foram obtidos trÃs misturas binÃrias de triterpenos pentacÃclicos das sÃries oleanano/ursano: 3-oxoolean-12-eno e 3-oxours-12-eno; 3Ã-hidroxiolean-12-eno e 3Ã-hidroxiurs-12-eno; 3Ã,16Ã-dihidroxiolean-12-eno e 3Ã,16Ã-di-hidroxiurs-12-eno; e quatro triterpenos tetracÃclicos da sÃrie tirucalano: Ãcido 3-oxotirucala-8,24-dien-21-Ãico, Ãcido 3a-hidroxitirucala-8,24-dien-21-Ãico, Ãcido 3a-acetoxitirucala-8,24-dien-21-Ãico e o Ãcido 3a-hidroxitirucala-7,24-dien-21-Ãico. Da cera epicuticular das folhas do PHB foram obtidos misturas de trÃs hidrocarbonetos lineares, heptacosano, hentriacontano e tritriacontano, e mistura de Ãsteres etÃlicos, tendo como constituinte principal o hexadecanoato de etila. Da resina do PHU foram obtidas duas misturas binÃrias de triterpenos pentacÃclicos das sÃries oleanano/ursano: 3-oxoolean-12-eno e 3-oxours-12-eno; 3Ã-hidroxiolean-12-eno e 3a-hidroxiurs-12-eno; trÃs triterpenos tetracÃclicos da sÃrie tirucalano: Ãcido 3-oxotirucala-8,24-dien-21-Ãico, Ãcido 3ahidroxitirucala-8,24-dien-21-Ãico e Ãcido 3a-hidroxitirucala-7,24-dien-21-Ãico, e um triterpeno pentacÃclco da sÃrie friedelano, D:A-friedoolean-3-ona. Do Ãleo essencial do PHU foram isolados dois monoterpenos: o terpinoleno e o p-cimen-8-ol. O Ãleo essencial das resinas do PHB, PHU e PHH, apresentaram como constituintes principais, a-pineno (21,28%), terpinoleno (42,31%) e p-cimeno (31,50%), respectivamente. Esses Ãleos mostraram atividade biolÃgica frente aos microorganismos Bacillus subtilis, Klebsiella pneumoniar, Staphylococcus aureus, Escherichia coli, Nycobacterium phlei. Especificamente, o Ãleo essencial do PHB apresentou atividade contra larvas do mosquito Aedes aegypti, apresentado CL50 = 270,32 ppm, considerado insuficiente. Algumas reaÃÃes de derivatizaÃÃo foram realizadas com o intuito de comprovaÃÃo estrutural, como tambÃm, para destacar, em parte, a quÃmica propriamente dita. Finalmente, foi verificada a possibilidade de utilizaÃÃo das enzimas imobilizadas da resina do PHB como biocatalisador, em reaÃÃo de acetilaÃÃo. / This work presents study phytochemistry of three species of plants of the family Burseraceae: Protium hebetatum Daly (PHB), Protium heptaphyllum (Aublet) Marchand subsp. ulei (Swat) Daly (PHU) and the Protium heptaphyllum (Aublet) Marchand subsp. heptaphyllum (PHH), known, at random, as pitch, pitch-white and almÃcego. The species were collected in the municipal district of Cruzeiro do Sul, Acre, Brazil. Of the resin of PHB, were obtained three binary mixtures of triterpenes pentacyclics of the series oleanane/ursane: 3-oxoolean-12-ene and 3-oxours-12-ene; 3Ã-hydroxyolean-12-ene and 3Ã-hydroxyurs-12-ene; 3Ã,16Ãdihydroxyolean- 12-ene and 3Ã,16Ã-dihydroxyurs-12-ene; and four triterpenes tetracyclic of the series tirucallane: 3-oxotirucalla-8,24-dien-21-oic acid, 3a-hydroxytirucalla-8,24-dien-21-oic acid, 3a-acetoxytirucalla-8,24-dien-21-oic acid and the 3a-hydroxytirucalla-7,24-dien-21-oic acid. Of the epicuticular wax of the leaves of PHB were extracted mixtures of three hydrocarbons: heptacosane, hentriacontane and tritriacontane, and mixture of ethyl ester, as main constituent, the ethyl hexadecanoate. Of the resin of PHU were obtained two binary mixtures of triterpenes pentacyclics of the series oleanane/ursane: 3-oxoolean-12-ene and 3-oxours-12-ene; 3Ã-hydroxyolean-12-ene and 3a-hydroxyurs-12-ene; three triterpenes tetracyclics of the series tirucallane: 3-oxotirucalla-8,24-dien-21-oic acid, 3ahydroxytirucalla- 8,24-dien-21-oic acid and the 3a-hydroxytirucalla-7,24-dien-21-oic acid and one triterpene pentacyclic of the series friedelane: D:A-friedoolean-3-one. From the essential oil of PHU, were isolated two monoterpenes: the terpinolene and the p-cymen-8-ol. The essential oil of the resins of PHB, PHU and PHH, presented as main constituent a-pinene (21.28%), terpinolene (42.31%) e p-cymene (31.50%), respectively. Those oils showed biological activity to the microorganism: Bacillus subtilis, Klebsiella pneumoniar, Staphylococcus aureus, Escherichia coli, Nycobacterium phlei. Specifically, the essential oil of PHB was analyzed his activity against larva of the mosquito Aedes aegypti, presenting CL50 = 270.32 ppm, considered donât activate. Some reactions were performed with the intention of structural proof, as well as, to detach, in part, the chemistry. Finally, was verified the possibility of using the immobilized enzymes of the resin of PHB as biocatalyst, in acetylation reaction.