Antimicrobial activity and chemical investigation of Brazilian Drosera

The antimicrobial activity of three different extracts (hexanic, ethyl acetate, methanol) obtained from Brazilian Drosera species (D. communis, D. montana var. montana, D. brevifolia, D. villosa var. graomogolensis, D. villosa var. villosa, Drosera sp. 1, and Drosera sp. 2 ) were tested against Staphylococcus aureus (ATCC 25923), Enterococcus faecium (ATCC23212), Pseudomonas aeruginosa (ATCC27853), Escherichia coli (ATCC11229), Salmonella choleraesuis (ATCC10708), Klebsiella pneumoniae (ATCC13883), and Candida albicans (a human isolate). Better antimicrobial activity was observed with D. communis and D. montana var. montana ethyl acetate extracts. Phytochemical analyses from D. communis, D. montana var. montana and D. brevifolia yielded 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin); long chain aliphatic hydrocarbons were isolated from D. communis and from D. villosa var. villosa, a mixture of long chain aliphatic alcohols and carboxylic acids, was isolated from D. communis and 3b-O-acetylaleuritolic acid from D. villosa var. villosa

Microhabitat preferences of six Drosera (Droseraceae) from Tibagi river basin, Paraná state, Brazil

We studied the microhabitats and the climatic requirements of six Drosera taxa, which occur in the subtropical grasslands of the Tibagi river basin. They are annual,or most communly, perennial herbs known as carnivorous plants, whose leaves are transformed into traps for the capture and digestion of small insects as an adaptation for supplying nutricional deficiencies. They usually occur in distrophic substrata. In order to contribute to conservation plans for the species of the genus, threatened by the conversion of the natural grasslands into pastures, we tried to define their preferential habitats and climatic requirements. We verified that the variables of microhabitat and altitude presented significant correlation at 5% probability level, while the variables in annual average relative humidity, annual average temperature and type of substratum types did not show significant correlation.<br>Nós estudamos os microhabitats e as exigências climáticas de seis taxa de Drosera (Droseraceae), que ocorrem nos campos subtropicais da bacia do rio Tibagi. São ervas perenes, conhecidas como plantas carnívoras, cujas folhas são transformadas em armadilhas para a captura e digestão de pequenos animais, o que tem sido referido como adaptação para suprir deficiências nutricionais, já que geralmente ocorrem em substratos distróficos. Para auxiliar na elaboração de planos de conservação para as espécies do gênero, ameaçadas pela conversão dos campos em pastagens, nós procuramos definir os habitats preferenciais e as exigências climáticas. Verificou-se que as variáveis: tipo de microhabitat e altitude apresentam correlação significativa no nível de 5%, enquanto as variáveis: umidade relativa média anual, temperatura média anual e tipo de substrato, não apresentaram correlação significativa. Os resultados obtidos sugerem que a distribuição dos taxa de Drosera estudados está relacionada principalmente com a variação de altitude e o tipo de microhabitat