Recebido em 19/8/08; aceito em 28/1/09; publicado na web em 3/7/09 SEASONAL VARIATION OF THE COMPOSITION OF ESSENTIAL OIL FROM Myrcia salzmannii Berg. (Myrtaceae). This work report the seasonal variation of composition of the volatile oils from leaves and from flowers of Myrcia salzmannii harvested in the sand dunes of Salvador, Bahia, northeastern region of Brazil in the years 2001 and 2003. The oils were analyzed by GC-FID and GC-MS being identified 49 components. Nine essential oil samples of leaves collected on different months and years and one sample of flowers were analyzed. β-Caryophyllene and α-humulene were the only compounds present in all of the samples being the first the majority compound.Keywords: Myrcia salzmannii; essential oil; terpenes. INTRODUÇÃOAs plantas aromáticas têm sido utilizadas desde a Antigüidade como antissépticos e agentes anti-infecciosos, para dar aroma a perfumes e cosméticos e como flavorizantes em alimentos e bebidas. Suas propriedades biológicas estão diretamente relacionadas com a composição química, a qual pode ser afetada pelas variações ambiental, geográfica, sazonal e circadiana.As espécies da família Myrtaceae são particularmente ricas em óleos essenciais. Essa família é constituída de 140 gêneros e aproximadamente 3000 espécies 1 com dois principais centros de desenvolvimento, a América tropical e a Austrália, embora ocorram em outras regiões no mundo.2 O gênero Myrcia é um dos maiores da família com cerca de 300 espécies e muito bem representado em todo o território brasileiro. Espécies desse gênero têm sido utilizadas na medicina popular como adstringentes, diuréticos, contra o Diabetes mellitus, para estancar hemorragias e no tratamento de hipertensão e úlceras. 3Relativamente ao seu grande número, são poucas as publicações acerca da química das espécies do gênero Myrcia. Em M. citriofolia, foi relatada a ocorrência de eucaliptina, uma flavona C-metilada.4 O extrato metanólico de M. multiflora mostrou potente atividade inibitória da aldose redutase, 5,6 uma enzima que está relacionada com algumas complicações do Diabetes mellitus. 7,8 O fracionamento desse extrato levou ao isolamento de flavanonas glicosiladas (myrciacitrinas I e II) e acetofenonas glicosiladas (myrciafenonas A e B). Os óleos essenciais de 17 espécies do gênero já foram estudados e ficou demonstrado que os sesquiterpenos foram predominantes em todos eles exceto em M. myrtifolia, 9 em que houve uma larga predominância de monoterpenos e M. acuminatissima e M. bombycina, nos quais o conteúdo de monoterpenos foi apenas ligeiramente maior que o de sesquiterpenos.

The resistance of microorganisms to current antimicrobials, and the deleterious effects caused by the excessive free radical manufacturing in the human body and their relationship with increasing global incidence of cancer, has led to a continuous search for new chemical agents that can contribute to the fight against these ills. The objective of the present work was to evaluate the antimicrobial, antioxidant and cytotoxic activities and determine the chemical profile of ethyl acetate extract of ten species of the family Melastomataceae. Antimicrobial activity was assessed by the methods of disk diffusion in agar and microdilution in broth (MIC-µg/mL). Antioxidant activity was measured by DPPH free radical capture assay while toxicity was evaluated with Artemia salina Leach. Cytoxicity was evaluated by in vitro tests with THP-1-cells. Identification of the classes of metabolites was performed using chemical reagents, while quantification of total phenols (EGA/g) and total flavonoids (EQ/g) was done by spectrophotometry. The extract of Clidemia capitellata exhibited activity against Micrococcus luteus with MIC = 62.5-μg/mL. The extract of C. hirta had the highest sequestering activity of DPPH free radicals (63.54-%). The toxicological assay revealed high toxicity for Miconia alborufescens extract (CL 50 61.6-μg/mL). Cytotoxic activity of extracts for THP-1-cells was observed through visualization of apoptotic bodies and cell death. Phytochemical analysis detected the presence of condensed tannins, terpenes, steroids and polyphenols, and the absence of alkaloids. The assays performed provided promising results, suggesting the continuation of new chemical-pharmacological evaluations and the isolation of the active principle of the extracts.

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It is widely accepted that voltage-dependent anion-selective channel (VDAC) inserts into planar lipid bilayers in a random orientation. This is in contrast to the well-documented oriented insertion of various channel-forming proteins. Because of the potential importance of this issue, we have examined the orientation of VDAC inserted in membranes. The time constants of the VDAC-current relaxation in response to applied positive and negative voltage pulses were used to characterize the channel orientation. We have found that VDAC channels can be separated into two groups according to differences in the time constant ratio. The difference in time constant ratio between the two main groups of VDAC channels was quantitative, and not qualitative as would be expected for opposite topologies. This finding allows us to hypothesize that both groups of VDAC channels possess a qualitatively similar asymmetry with respect to the localization of voltage-gated domains and, consequently, with respect to its entire molecular structure. The probability of having each type of VDAC channel conformation is predetermined by the protein structure in aqueous solution. A striking resemblance between asymmetry in voltage sensitivity at the single-channel and multi-channel levels was also demonstrated. The first inserted channel seems to direct subsequent insertions of channels with a similar conformation.

BackgroundCorynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis (CL), a chronic disease that affects goats and sheep. CL is characterized by the formation of granulomas in lymph nodes and other organs, such as the lungs and liver. Current knowledge of CL pathogenesis indicates that the induction of humoral and cellular immune responses are fundamental to disease control. The aim of this study was to evaluate the humoral and cellular immune responses in BALB/c mice inoculated with a C. pseudotuberculosis strain isolated in the state of Bahia, Brazil.ResultsThe lymphocyte proliferation and in vitro production of IFN-γ, IL-4, IL-10, IL-12 and nitric oxide by spleen cells stimulated with secreted and somatic antigens from the studied strain were evaluated. IgG subclasses were also analyzed. Results showed a significant increase of Th1-profile cytokines after 60 days post-inoculation, as well as an important humoral response, represented by high levels of IgG2a and IgG1 against C. pseudotuberculosis.ConclusionThe T1 strain of C. pseudotuberculosis was shown to induce humoral and cellular immune responses in BALB/c mice, but, even at a dosage of 1x107 CFU, no signs of the disease were observed.