The objective of this work was to evaluate the insecticidal activity of a botanical formulation with neem (Azadirachta indica) oil and D-limonene for the control of Hypothenemus hampei, as well as to determine the fatty acid composition of neem oil. Ninety-five percent neem oil was extracted from cold-pressed A. indica seeds, and D-limonene, from citrus peel. Humic extract (organic carbon), potassium, calcium, magnesium, and sulfur were included as additives. The analysis of neem oil by gas chromatography coupled to mass spectrometry showed that linoleic acid (49.28%) is the main fatty acid in its composition. Field tests were carried out on 'Topázio MG 1190' coffee (Coffea arabica) trees, with four applications of the formulated compound every 20 days for a period of 64 days. For the evaluation of insecticidal activity, the botanical formulation was applied to filter paper or topically on the insect’s dorsal side, showing a mortality of 63.34 and 100% after 48 hours, respectively. In the field, insecticidal activity caused a 62.4% reduction in the incidence of the H. hampei population, when compared with the control. The evaluated botanical formulation is efficient in controlling H. hampei in coffee plants.
Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize substances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octadecanoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol.
pelo companheirismo, amizade e ajuda na utilização de todos os softwares necessários para elucidação de substâncias orgânicas deste trabalho. Ao Prof. Dr. Rodrigo Muñoz, coordenador da Pós-Graduação do Instituto de Química, que desde o início se empenhou na minha chegada e fixação no programa. Aos meus pais, Edson e Ana Maria, pelo apoio, dedicação e incentivo à minha formação. Aos meus irmãos por serem meus presentes de vida, e motivo para minha luta por um futuro melhor. As minhas sobrinhas por me descontraírem em momentos tensos de estudos. A minha noiva, Laura Ravenna porestar comigo em todo o tempo, e por me motivar a lutar por bons ideais. À FAPEMIG (APQ01392-14 A.O., APQ02481-14 M.P e APQ02342-18 R.M.F.S, CEX-RED00010-14 Rede Mineira),CAPES e CNPq (449846/2014-8M.P) e pelos incentivos com as bolsas e projetos aprovados. E por fim, ao Instituto de Química da UFU e ao seu Programa de Pós-Graduação em Química, que possibilitaram o desenvolvimento deste trabalho. Palavras-chave: Fungos entomopatogênicos e fitopatogênicos; Metabólitos secundários; Cromatografia gasosa acoplada a espectrometria de massas; CG-MS; Atividade antibacteriana.
Tibolone (TIB) is a synthetic steroid banned by the World Anti‐Doping Agency (WADA) due to its similar properties to estrogen and progesterone. In this work, a simple and low‐cost electrochemical method for the determination of TIB and its metabolites (3‐α hydroxytibolone and 3‐β hydroxytibolone) in authentic human saliva is reported. Square‐wave voltammetry (SWV) with an unmodified boron‐doped diamond (BDD) electrode and phosphate buffer 0.1 mol L−1 were selected as the electrochemical technique, working electrode, and supporting electrolyte, respectively. Analytical characteristics of the proposed method include good repeatability (RSD <2.4 %), wide linear range (1 to 110 μmol L−1; r=0.999) and low detection limit (0.3 μmol L−1). Average recovery values (104±3 % for TIB and 98±5 % for the metabolites) for direct analysis of spiked saliva samples (only diluted in supporting electrolyte) indicate that no significant matrix interference was observed. The proposed method was also efficient for the determination of TIB in pharmaceutical samples (statistically similar results to those obtained by HPLC).
O caruru (Amaranthus spp.) é considerado uma espécie daninha de difícil manejo e de grande importância para agricultura. O objetivo do trabalho foi avaliar a atividade fitotóxica de um filtrado de cultura produzido por Cercospora brachiata, patógeno foliar de A. viridis, sobre a germinação de sementes e desenvolvimento de plantas de caruru, sorgo e pepino. O fungo foi cultivado em meio de cultura líquido e o extrato fúngico bruto, obtido a partir da extração em acetato de etila, foi concentrado e submetido a teste para avaliação da atividade fitotóxica sobre sementes e plantas de caruru, sorgo e pepino. Para o teste com sementes, 20 sementes de cada espécie foram transferidas para placas de Petri contendo papel de germinação embebido com 3 mL de cada tratamento: T1 (extrato fúngico bruto + dimetilsulfóxido (CH₃)₂SO), T2 (dimetilsulfóxido (CH₃)₂SO) (branco) e T3 (água estéril). Para o experimento com plantas, foram utilizados os mesmos tratamentos descritos anteriormente, acrescidos de Tween 80 a 0,05% (m v -1). Cada parcela continha uma planta de cada espécie por vaso, cinco repetições e diferentes estádios fenológicos (2, 4 e 6 folhas). Em cada estádio foram feitas 3 aplicações de 3 mL planta-1 em intervalos de 3 dias. O extrato fúngico de C. brachiata inibiu totalmente a germinação de sementes de A. viridis. Metabólitos de C. brachiata apresentam atividade inibitória pronunciada sobre o crescimento de plantas de A. viridis e não afetaram nenhum parâmetro fisiológico tanto para pepino quanto para sorgo. Foram identificados ácidos de cadeia longa e ésteres de ácidos graxos a partir do filtrado de cultura de C. brachiata.
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