Os óleos essenciais das folhas, flores e frutos de Myrcia myrtifolia DC foram coletados ao longo dos anos de 2002 e 2003 e foram analisados utilizando CG-DIC e CG-EM. No total foram identificados 28 componentes sendo que o α-pineno foi a substância predominante em todas as amostras analisadas apresentando-se em concentrações que variaram entre 61.5 e 90.9%. As propriedades antimicrobianas do óleo essencial das folhas coletadas em outubro de 2002 foram avaliadas contra seis bactérias, duas leveduras e cinco fungos filamentosos sendo mais fortemente ativo contra Microsporum canis e Trichophyton rubrum, ativo contra Staphylococcus aureus, Staphylococcus aureus resistente à meticilina, Candida albicans, Cryptococcus neoformans e Aspergillus fumigatus. O óleo ainda mostrou uma toxicidade moderada, LC 50 of 479,16 μg mL -1 , contra Artemia salina.This work reports the seasonal variation of the composition of leaf volatile oils and the composition of volatile oils from flowers and fruits of Myrcia myrtifolia DC harvested in the sand dunes of Salvador, Bahia, northeastern region of Brazil between 2002 and 2003. The oils were analyzed by GC-FID and GC-MS so that 28 components were identified. α-Pinene was predominant in a range from 61.5 to 90.9% in all samples analyzed. The leaf oil collected in October 2002 had their antimicrobial properties tested against six bacteria, two yeasts and five filamentous fungi being active against Staphylococcus aureus, methicilin-resistant Staphylococcus aureus, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, and showed strongest activity against Microsporum canis and Trichophyton rubrum. The oil displayed moderate toxicity against Artemia salina showing a LC 50 of 479.16 μg mL -1 .Keywords: Myrtaceae, Myrcia myrtifolia, essential oil, monoterpene, sesquiterpene, antimicrobial activity IntroductionAromatic plants have been used since ancient times as antiseptics and anti-infectious agents, as aroma in perfumes and cosmetics as well as preservative and flavour ingredients in food and beverages. Their biological properties are directly related with their chemical compositions, which can be affected by environmental, geographical, seasonal and circadian variations.The family Myrtaceae is constituted by 140 genera with about 3000 species, which are widely distributed in America and Australia. 1 The genus Myrcia comprises more than 300 species that grow in all Brazilian territory. Indigenous tribes and traditional Brazilian communities have used several species of this genus as astringent, against diabetes and diarrhea, as diuretic, to stanch hemorrhages, against the hypertension and ulcers of the mouth. 2 Some works were published regarding the chemistry and the biological properties of Myrcia species. From M. citriofolia, the occurrence of a C-methylated flavone, eucalyptin, was related, 3 from the methanolic extract of M. multiflora were isolated flavonol, flavanone and acetophenone glucosides along with myricitrin, mearnssitin, quercitrin, desmanthin-1 and guaijaverin...

A espécie Poiretia bahiana, popularmente conhecida como arrudinha, arruda da serra ou arruda brava, tem uma ocorrência restrita aos campos rupestres da Chapada Diamantina, BA. Suas partes aéreas apresentam um aroma pungente e é usada pelo povo do local no controle de infestações por pulgas e no tratamento de hemorróidas, dores nas articulações e sinusite. Neste trabalho, relatamos a composição dos óleos voláteis obtidos das partes aéreas de cinco espécimes e do óleo volátil obtido dos frutos de um espécime de P. bahiana, os quais foram coletados em diferentes regiões da Chapada Diamantina. Nos óleos voláteis que foram analisados por CG-FID e CG-EM foram identificados vinte e nove componentes sendo que os dois principais foram a umbelulona, em concentrações entre 55,0% e 75,3%, e sabineno, em concentrações entre 10,3% e 25,2%. O óleo das partes aéreas de um espécime e o óleo dos frutos de outro espécime foram avaliados quanto às suas propriedades antimicrobianas contra seis bactérias, duas leveduras e cinco fungos filamentosos pelos ensaios de difusão em ágar e microdiluição. Os óleos exibiram atividade contra Escherichia coli, Salmonella choleraesuis, Proteus mirabilis, Staphylococcus aureus, Staphylococcus aureus resistente à meticilina (MRSA), Candida albicans, Cryptococcus neoformans, Cladosporium herbarum, Microsporum canis, Trichophyton rubrum e foram inativos contra Pseudomonas aeruginosa, Aspergillus fumigatus e Penicillium notatum. A toxicidade do óleo das partes aéreas foi determinada contra Artemia salina apresentando uma LC 50 de 459,03 mg mL -1 .Poiretia bahiana known as "arrudinha", "arruda da serra" or "arruda brava", has its occurrence restricted to the rock fields (campo rupestre) areas in Chapada Diamantina, Bahia, northeastern region of Brazil. Its aerial parts present a pungent smell and have been used by local communities as fumigant for the control of infestation of fleas and in the treatment of hemorrhoids, articulations pain and sinusitis. This work reports the composition of the volatile oils from aerial parts of five specimens and of the essential oil from the fruits of one specimen of Poiretia bahiana that were harvested in four different places of Chapada Diamantina. Twenty nine components were identified from the oils analyzed by GC-FID and GC-MS. Umbellulone, in concentrations between 55.0% and 75.3% and sabinene, in concentrations between 10.3% and 25.2% are the major components. The oil from the aerial parts of one specimen and the oil of fruits of another specimen had their antimicrobial properties evaluated against six bacteria, two yeasts and five filamentous fungi by the agar diffusion method and microdilution assay. The in vitro results demonstrated that these essential oils exhibit antimicrobial activity against Escherichia coli, Salmonella choleraesuis, Proteus mirabilis, Staphylococcus aureus, methicilin resistant Staphylococcus aureus (MRSA), Candida albicans, Cryptococcus neoformans, Cladosporium herbarum, Microsporum canis, Trichophyton rubrum and are inactive against Pse...