Morfoanatomia, composição química do óleo essencial e atividade antimicrobiana das folhas e casca do caule de Myrcia tomentosa (Aubl.) DC.

• Autor(a) principal: SÁ, Fabyola Amaral da Silva
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/2093
• topic: Myrtaceae; Goiaba-brava; Atividade antifúngica; Plantas medicinais; 1.Morfoanatomia 2.Óleo essencial 3.Atividade antimicrobiana 4.Plantas medicinais; Myrtaceae; Goiaba-brava; Antifungal activity; Medicinal plants; CNPQ::CIENCIAS DA SAUDE::FARMACIA

The Brazilian Savanna is recognized as the richest in the world, sheltering more than 6.500 plant species already cataloged, and medicinal uses are attributed to over 220. Species of Myrtaceae family are used in folk medicine in gastrointestinal disorders, infectious diseases and hemorrhagic states, many are known by the presence of essential oils. The objective of this work was the pharmacognostic study of leaves and bark of species Myrcia tomentosa (Aubl.) DC. in order to establish quality parameters and to determine the chemical composition of essential oil (leaves, bark and flowers), as well as to assess the occurrence of seasonal variation between the chemical constituents of essential oil from leaves and to evaluate the antimicrobial activity of leaf essential oil, ethanolic crude extract and fractions from leaf and bark extracts. For this purpose, part of the botanical materials was used in microscopic analysis and in phytochemical analysis. The contents of total phenols, tannins and of total flavonoids were evaluated. The gas chromatography coupled to mass spectrometry (GC / MS) was used to characterize the chemistry of essential oils and the broth microdilution test was used for both evaluation of antimicrobial activity and determination of Minimum Inhibitory Concentration (MIC). In morpho-anatomical study of leaves, it was found that they are simple, leathery and predominantly opposing crossed. Microscopically are hypostomatic with numerous unicellular trichomes, have secretory cavities and idioblasts with prismatic crystals. The bark has flat, curved and sometimes channeled shape. At microscopic level, the bark shows prismatic crystals, sclereids and periderm is formed in the inner layers. In the phytochemical screening, it was found essential oils, tannins and terpenes in leaves and bark, only flavonoids in leaves and saponin in bark. In the essential oils analysis, it was found that (2E, 6E)-Methyl farnesoate is the major component in the flowers and bark essential oils, while the leaves essential oil showed seasonal variation in their chemical composition, with Bicyclogermacrene and (2E, 6E)-Methyl farnesoate as major components The antimicrobial evaluation of leaf essential oil showed activity for Micrococcus roseus, Bacillus subtilis, Bacillus cereus, Micrococcus luteus and Staphylococcus aureus (MIC = 125 - 250 μg/mL) and the fungi Cryptococcus neoformans and Cryptococcus gattii (MIC = 62,5 500 μg/mL); the fractions were moderate activity for most Gram-positive bacteria, and the hexane and dichlorometane fractions of the leaves, and ethyl acetate and aqueous bark were most active (MIC = 250 500 μg/mL). With respect to antifungal activity, the fractions tested showed good or moderate activity for Candida sp (MIC = 15,62 125 μg/mL) and hexanic and dichloromethanic fractions of leaves showed good activity for Cryptococcus sp (MIC = 15,62 62,50 μg/mL). The results contribute to the identification of the species M. tomentosa and demontrate its potential for the treatment of fungal diseases.