The antimicrobial activity of plant extracts and phytochemicals was evaluated with antibiotic susceptible and resistant microorganisms. In addition, the possible synergistic effects when associated with antibiotics were studied. Extracts from the following plants were utilized: Achillea millifolium (yarrow), Caryophyllus aromaticus (clove), Melissa offficinalis (lemon-balm), Ocimun basilucum (basil), Psidium guajava (guava), Punica granatum (pomegranate), Rosmarinus officinalis (rosemary), Salvia officinalis (sage), Syzygyum joabolanum (jambolan) and Thymus vulgaris (thyme). The phytochemicals benzoic acid, cinnamic acid, eugenol and farnesol were also utilized. The highest antimicrobial potentials were observed for the extracts of Caryophyllus aromaticus and Syzygyum joabolanum, which inhibited 64.2 and 57.1% of the tested microorganisms, respectively, with higher activity against antibiotic-resistant bacteria (83.3%). Sage and yarrow extracts did not present any antimicrobial activity. Association of antibiotics and plant extracts showed synergistic antibacterial activity against antibiotic-resistant bacteria. The results obtained with Pseudomonas aeruginosa was particularly interesting, since it was inhibited by clove, jambolan, pomegranate and thyme extracts. This inhibition was observed with the individual extracts and when they were used in lower concentrations with ineffective antibiotics.

Brazil is blessed with a great biodiversity, which constitutes one of the most important sources of biologically active compounds, even if it has been largely underexplored. As is the case of the Amazon and Atlantic rainforests, the Brazilian marine fauna remains practically unexplored in the search for new biologically active natural products. Considering that marine organisms have been shown to be one of the most promising sources of new bioactive compounds for the treatment of different human diseases, the 8000 km of the Brazilian coastline represents a great potential for finding new pharmacologically active secondary metabolites. This review presents the status of marine natural products chemistry in Brazil, including results reported by different research groups with emphasis on the isolation, structure elucidation, and evaluation of biological activities of natural products isolated from sponges, ascidians, octocorals, and Opistobranch mollusks. A brief overview of the first Brazilian program on the isolation of marine bacteria and fungi, directed toward the production of biologically active compounds, is also discussed. The current multidisciplinary collaborative program under development at the Universidade de São Paulo proposes to establish a new paradigm toward the management of the Brazilian marine biodiversity, integrating research on the species diversity, ecology, taxonomy, and biogeography of marine invertebrates and microorganisms. This program also includes a broad screening program of Brazilian marine bioresources, to search for active compounds that may be of interest for the development of new drug leads.

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RESUMO:Especialmente nas últimas décadas, inúmeros esforços têm sido dirigidos para conferir às plantas seu real papel e valor na terapia. Neste estudo foi avaliada a atividade antimicrobiana de extratos secos de Artemisia absinthium . To evaluate the antimicrobial activity the diffusion test in agar was carried through, with 15 different microorganisms, using discs impregnated with aqueous dispersions of the vegetal extracts. For those extracts that had presented inhibitory activity, the calculation of Minimum Inhibitory Concentration was carried out (CIM). The results had shown that the extracts of X. violaceum and S. cuminii had inhibited 8 and 6 bacteria, respectively. What leads to the conclusion that the extracts of X. violaceum and S. cuminii are capable to inhibit the microbial growth.

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A new antifungal agent, (2S,3R)-2-aminododecan-3-ol (1), has been isolated from the ascidian Clavelina oblonga collected in Brazil. The structure of 1 was established by analysis of spectroscopic data, including absolute stereochemistry determined by circular dichroism analysis of the dibenzoyl derivative 2. Compound 1 displayed antifungal activity against Candida albicans ATCC 10231 with a MIC of 0.7 mug/mL and against Candida glabrata with a MIC of 30 microg/mL.

RESUMO RESUMO RESUMO RESUMO RESUMO Foi avaliada a ocorrência de resíduos de antibióticos em 96 amostras de leites pasteurizados de 6 diferentes marcas adquiridas em estabelecimentos comerciais de

Recebido em 9/5/07; aceito em 30/11/07; publicado na web em 21/7/08Extracts obtained from 57 marine-derived fungal strains were analyzed by HPLC-PDA, TLC and 1 H NMR. The analyses showed that the growth conditions affected the chemical profile of crude extracts. Furthermore, the majority of fungal strains which produced either bioactive of chemically distinctive crude extracts have been isolated from sediments or marine algae. The chemical investigation of the antimycobacterial and cytotoxic crude extract obtained from two strains of the fungus Beauveria felina have yielded cyclodepsipeptides related to destruxins. The present approach constitutes a valuable tool for the selection of fungal strains that produce chemically interesting or biologically active secondary metabolites.