14 research outputs found
Larvicidal activity of Ramalina usnea lichen against Aedes aegypti
AbstractThe larvicidal activity of the methanol extract, fractions and compounds 2-hydroxy-4-methoxy-6-propyl-methyl benzoate and (+)-usnic acid identified from the lichen Ramalina usnea (L.) R. Howe, Ramalinaceae, was tested against the third instar larvae of the Aedes aegypti mosquito. The methanol extract and three fractions showed activity, killing 100% and 96.6% of the larvae at a concentration of 150μg/ml at 24h. The isolated compounds, 2-hydroxy-4-methoxy-6-propyl-methyl benzoate and the (+)-usnic acid showed larvicidal activity, presenting LC50 values of 4.85 and 4.48μg/ml, respectively. This is the first study of its kind reporting the larvicidal activity against the A. aegypti mosquito with compound (1)
Perfilhamento, acúmulo de forragem e composição bromatológica do capim-braquiária adubado com nitrogênio
Características morfogênicas e estruturais do capim-xaraés submetido à adubação nitrogenada e desfolhação
Recria de machos Nelore em pastagens cultivadas com suplementação na seca nos Cerrados do Brasil Central
Larvicidal activity of Ramalina usnea lichen against Aedes aegypti
The larvicidal activity of the methanol extract, fractions and compounds 2-hydroxy-4-methoxy-6-propyl-methyl benzoate and (+)-usnic acid identified from the lichen Ramalina usnea (L.) R. Howe, Ramalinaceae, was tested against the third instar larvae of the Aedes aegypti mosquito. The methanol extract and three fractions showed activity, killing 100% and 96.6% of the larvae at a concentration of 150 μg/ml at 24 h. The isolated compounds, 2-hydroxy-4-methoxy-6-propyl-methyl benzoate and the (+)-usnic acid showed larvicidal activity, presenting LC50 values of 4.85 and 4.48 μg/ml, respectively. This is the first study of its kind reporting the larvicidal activity against the A. aegypti mosquito with compound (1). Keywords: Larvicidal activity, Lichenized fungi, Ramalina usnea, Aedes aegypt
Antimicrobial activity and chemical analysis of <i>Microlicia hatschbachii</i> Wurdack (Melastomataceae) extract
<div><p>Aerial parts of <i>Microlicia hatschbachii</i> were extracted with hexane, and the extract was evaluated for antimicrobial activity by a broth dilution method. After phytochemical procedures: GC-MS identified aliphatic alkanes, carboxylic acids and methyl esters of long-chain fatty acids; and two diterpenoids [labd-8(17)-en-15-oic acid and labd-8(17),13-dien-15-oic acid] were identified by <sup>1</sup>H and <sup>13</sup>C NMR. The antimicrobial activity of the hexane extract could be attributed to the presence of labdanes. This identification is the first reported occurrence of labdane diterpenes in the Melastomataceae family.</p></div
Two fast screening methods (GC-MS and TLC-ChEI assay) for rapid evaluation of potential anticholinesterasic indole alkaloids in complex mixtures
The pharmacotherapyfor Alzheimer's disease (AD) includes the use of acetylcholinesterase inhibitors (AChEI). Recent investigations for novel AD therapeutic agents from plants suggested that Tabernaemontana genus is a promising source of novel anticholinesterasic indole alkaloids. In this work two fast screening techniques were combined in order to easily identify novel cholinesterase inhibitors (ChEI). Gas chromatography-mass spectrometry (GC-MS) of the less polar alkaloidic fractions obtained from the acid-base extraction of the stalk of T. laeta revealed thirteen monoindole alkaloids, four of them confirmed by co-injection with previously isolated alkaloids. The others were tentatively identified by mass fragmentation analysis. By gas chromatography with flame ionization detection (GC-FID) and using isatin as internal standard, affinisine and voachalotine were determined as major compounds. These fractions and fourteen previously isolated alkaloids, obtained from root bark of T. laeta and T. hystrix were investigated for acetyl (AChE) and butyrylcholinesterase (BuChE) inhibitory activities by the modified Ellman's method in thin layer chromatography(TLC-ChEI). Results showed selective inhibition of the alkaloids heyneanine and Nb-methylvoachalotine for BuChE, and 19-epi-isovoacristine for AChE, whereas olivacine, affinisine, ibogamine, affinine, conodurine and hystrixnineinhibited both enzymes. In addition to confirming that monoterpenoid indole alkaloids can be novel therapeutic agents for AD, this is the first report of the ChEI activity of olivacine, a pyridocarbazole alkaloid