Aerial parts of Elyonurus muticus were collected in the four seasons of the year in the Brazilian Pantanal and subjected to extractrion with cold ethanol and to hydrodistillation. Sesquiterpenoids (E)-caryophyllene, bicyclogermacrene, spathulenol and caryophyllene oxide were the main components identified in the essential oils and their concentrations varied according to the plant collection period. The essential oils and the ethanolic crude extracts were active against Bacillus cereus MIP 96016, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923 and were not active against Escherichia coli ATCC 25922. The antibacterial activities varied according to the plant collection period.

Ethanol extracts from six selected species from the Cerrado of the Central-Western region of Brazil, which are used in traditional medicine for the treatment of infectious diseases and other medical conditions, namely Erythroxylum suberosum St. Hil. (Erythroxylaceae), Hyptis crenata Pohl. ex Benth. (Lamiaceae), Roupala brasiliensis Klotz. (Proteaceae), Simarouba versicolor St. Hil. (Simaroubaceae), Guazuma ulmifolia Lam. (Sterculiaceae) and Protium heptaphyllum (Aubl.) March. (Burseraceae), as well as fractions resulting from partition of these crude extracts, were screened in vitro for their antifungal and antibacterial properties. The antimicrobial activities were assessed by the broth microdilution assay against six control fungal strains, Candida albicans, C. glabrata, C. krusei, C. parapsilosis, C. tropicalis and Cryptococcus neoformans, and five control Gram-positive and negative bacterial strains, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Toxicity of the extracts and fractions against Artemia salina was also evaluated in this work. All plants investigated showed antimicrobial properties against at least one microorganism and two species were also significantly toxic to brine shrimp larvae. The results tend to support the traditional use of these plants for the treatment of respiratory and gastrointestinal disorders and/or skin diseases, opening the possibility of finding new antimicrobial agents from these natural sources. Among the species investigated, Hyptis crenata, Erythroxylum suberosum and Roupala brasiliensis were considered the most promising candidates for developing of future bioactivity-guided phytochemical investigations.

Recebido em 17/10/05; aceito em 14/6/06; publicado na web em 28/11/06 CHEMICAL COMPOSITION AND EVALUATION OF ALLELOPATHIC POTENTIALS OF Adiantum tetraphyllum HUMB. & BONPL. EX. WILLD (PTERIDACEAE). Chemical studies of green leaves of A. tetraphyllum afforded β-sitosterol, a mixture containing the ethyl esters of long chain carboxylic acids, 30-normethyl-lupan-20-one, hopan-22-ol, phytol, phyten-3(20)-1,2-diol, quercetin and quercetin-3-O-β-D-glucoside. The structures of the compounds were elucidated by spectroscopic and GC analysis. The allelopathic potentials of the crude ethanolic extract and fractions were evaluated against Lactuca sativa (letuce) and Allium cepa (onion) seeds.

a b s t r a c tThe phytochemical study of Nectandra cuspidata led to the isolation and characterization of the new megastigmane 7-megastigmen-3b,6b,9x-triol (1), the aporphinoid alkaloids (À)-glaziovine (2) and (þ)-apoglaziovine (3), the sesquiterpene costic acid (4), polyprenols (5, 6 and 8), a-tocopherol (7) and the steroid b-sitosterol (9). The structures of the compounds were elucidated based on spectroscopic data. This is the first description of the presence of megastigmanes in Nectandra genus. All compounds (1-9) were isolated for the first time from this species. The chemotaxonomic significance of these compounds was also summarized.

Frente à importância de debatesconceituais para o avanço das teorias e aconsolidação do campo da Comunicaçãoe as relações que se estabelecem com astransformações da sociedade, buscamos,neste artigo, contribuir para a discussãoem torno do conceito de dispositivosinteracionais, bem como sua inserçãoe funcionamento enquanto parte dofenômeno da sociedade em midiatização.Para isso, contextualizamos a referidasociedade a partir dos agenciamentosentre campos e a ascensão da mídiacomo “processo interacional dereferência” (BRAGA, 2006). Discutimosconceitualmente o dispositivo, desde aproposição foucaultiana, passando pelasformulações de Agamben, até chegar àconstrução do dispositivo interacionalproduzido nas interações midiatizadascontemporâneas.