David Lee Nelson

A convenient method for the determination of moisture in aromatic plants

A method is proposed for the determination of the moisture content of aromatic plants. This method is based on the co-distillation of the starting material in a modified Clevenger apparatus with four organic solvents (toluene, cyclohexane, dichloromethane and carbon tetrachloride). The results were compared with those obtained by oven drying at 105 oC and steam distillation of the essential oil. The efficiencies of the methods were shown to be equivalent. The solvent distillation method was more practical, especially with respect to operating time (2 h).

Determination of ethyl carbamate in cachaça produced from copper stills by HPLC

Ethyl carbamate (EC) is a common substance in fermented foods and drinks, and its quantification is important because of its carcinogenic nature and its usually presence in alcoholic beverages. The present work involved the development and validation of an analytical method for the evaluation of EC in cachaça by HPLC-FLD after previous derivatization with xanthydrol. The method presented a mean recovery of 94.88%, an intra-day precision of 4.19% (30.0 μgL(-1)) and 3.32% (75.0 μgL(-1)), a coefficient of determination (r(2)) equal to 0.9985, and limits of detection and quantification equal to 6.39 and 21.32 μgL(-1), respectively. The results show that the analytical method is accurate, reproducible and linear over the concentration range from 5.0 to 160 μg of EC per litre. The method was applied to the analysis of EC in cachaça, the analyses being rapid and efficient.

Influence of radiation level on plant growth, yield and quality of essential oil in carqueja

A influencia do nivel de radiância no crescimento da planta, rendimento e qualidade do oleo essencial de Baccharis trimera foi estudado neste trabalho. As plantas foram cultivadas sob 4 niveis de radiância: 100, 60, 50 e 20% durante um periodo de 259 dias. Foram avaliadas, quanto ao comprimento, numero de nos, ramos, diâmetro do caule (altura do colo), acumulo de fitomassa, conteudo e composicao do oleo essencial. O nivel mais elevado de radiacao causou aumento em todas as caracteristicas avaliadas, exceto para o comprimento, que foi reduzido com o aumento na radiacao. O rendimento de oleo essencial tambem aumentou com a elevacao do nivel de radiância.

Caracterização e quantificação de contaminantes em aguardentes de cana

The objective of the present study was the evaluation of the presence of organic and inorganic contaminants in samples of aged cachaca from the South of the state of Minas Gerais. Furfural, methanol and copper were determined by colorimetric reactions, while the analyses of ethyl carbamate and acrolein were performed by GC/MS and HPLC, respectively. High levels of furfural and copper were obtained. All samples showed concentrations below the established by legislation for the ethyl carbamate, and for acrolein, only one sample showed higher levels. Methanol was not detected in the samples.

Technetium-99m ceftizoxime kit preparation

The aim of this work was to prepare a kit of 99mTc-ceftizoxime (99mTc-CFT), with stability and biological activity preserved, able to identify a septic focus (E. coli) in the experimental infection model in rats. The preparation of the CFT kit involved the use of lyophilized solutions containing the antibiotic ceftizoxime and the sodium dithionite reducing agent (6.0 mg/mL). After lyophilization, the kit was reconstituted with 1.0 mL of sodium 99mTc-pertechnetate solution (Na99mTcO4-) with an activity of 370 MBq. The solution was boiled for 10 min and filtered through a cellulose ester filter. The labeling efficiency was on the order of 92%, remaining stable for six hours and the kit remained stable for two months. The biological activity of the 99mTc-CFT was evaluated by diffusion in agar impregnated with E.coli and S. aureus. Seven Wistar rats, weighing from 200 to 250 g, were used for the development of the septic focus. After 24 hours from the induction of the infectious site (E.coli), the animals were anesthetized and 0.1 mL of 99mTc-CFT (37 MBq) was injected into the tail veins of the animals. The images were obtained with a gamma camera one, two and six hours after injection and the regions of interest (ROIs) were calculated. The diameters of the inhibition halos for 99mTc-CFT were 27.16 ± 0.23 and 27.17 ± 0.20 for S.aureus and E.coli, respectively, while those for the unlabeled CFT were 30.4 ± 0.33 and 29.43 ± 0.26, respectively. The results for the biodistribution of 99mTc-CFT in infected animals furnished a ratio of 1.97 ± 0.31, 2.10 ± 0.42 and 2.01 ± 0.42 for cpm-target/cpm-no target for the one, two and six-hour periods, respectively. The images showed a clear uptake of labeled antibiotic (99mTc-CFT) by the infectious site during the experiment. The results attest to the viability of producing a kit with 99mtechnetium-labeled ceftizoxime for the investigation of infectious processes.

Antischistosomal activity of aminoalkanethiols, aminoalkanethiosulfuric acids and the corresponding disulfides.

This paper discusses the development of a series of sulfur-containing compounds that show an interesting in vivo activity against infection by Schistosoma mansoni. These substances include the aminoalkanethiols, aminoalkanethiosulfuric acids and aminoalkyl disulfides, among others. Although the aminoethanethiols and their disulfide derivatives have presented a relatively high toxicity for the host animal, the aminoalkanethiosulfuric acids have a low toxicity and a high specificity for the adult female S. mansoni worms. In vitro studies with schistosomula, lung-phase schistosomula and adult worms have demonstrated effects on the tegument and the metabolism on these different stages of S. mansoni worms. The encapsulation of these drugs in a nanoemulsion has resulted in an increase in the in vitro activity.

Sugars, organic acids, minerals and lipids in jabuticaba

O objetivo deste trabalho foi determinar a composicao dos acucares, acidos orgânicos e minerais do fruto inteiro e fracoes (casca, polpa e semente) dos genotipos de jabuticabeira Paulista (Plinia cauliflora) e Sabara (P. jaboticaba), assim como a composicao do oleo das cascas e sementes. As frutas apresentaram elevados teores de acucares totais, destacando-se a frutose, seguida de glicose e sacarose. No genotipo Paulista, foram encontrados teores mais elevados de acucares totais e redutores na polpa e na casca, o que nao foi observado ao comparar os frutos inteiros dos dois genotipos. Foram encontrados cinco acidos orgânicos na seguinte ordem quantitativa: acido citrico > acido succinico > acido malico > acido oxalico > acido acetico. Potassio foi o mineral mais abundante encontrado. A fruta mostrou tambem ser rica em magnesio, fosforo, calcio e cobre. O oleo das sementes mostrou ter praticamente a mesma constituicao do oleo extraido das cascas, e os compostos majoritarios foram um fitosterol nao identificado, os acidos palmitico, linoleico e oleico e o esqualeno.

Evolution of the concentration of phenolic compounds in cachaça during aging in an oak (Quercus sp.) barrel

A cachaca, tradicional e popular bebida brasileira, e obtida por meio da destilacao do mosto fermentado de cana de acucar. Dentre as etapas do processo de producao da bebida, o envelhecimento natural consiste em armazena-la em recipientes de madeira apropriados por um tempo determinado, onde ocorrem alteracoes na composicao quimica, aroma, sabor e cor da bebida. Este trabalho teve como objetivo realizar um acompanhamento da composicao fenolica em diferentes periodos de envelhecimento da cachaca em tonel de carvalho (Quercus sp.). Foram realizadas coletas periodicas durante o periodo de envelhecimento da cachaca em tonel de carvalho e realizaram-se analise de treze compostos fenolicos utilizando a tecnica de cromatografia liquida de alta eficiencia com detector de arranjo de diodos (HPLC-DAD). Foi constatado um aumento progressivo na concentracao dos compostos analisados ao longo do periodo analisado, sendo que os compostos encontrados em maior concentracao foram siringaldeido e acido galico.

EFFICACY OF A NEW SCHISTOSOMICIDAL AGENT 2-(METHYLPROPYL)AMINO-1-OCTANETHIOSULFURIC ACID AGAINST AN OXAMNIQUINE RESISTANT SCHISTOSOMA MANSONI ISOLATE

Departamento de Análises Clínicas, Faculdade de Farmácia e Bioquímica, UFJF, Campus Universitário, 36036-330 Juiz de Fora, MG, Brasil *Departamento de Parasitologia, Instituto de Ciências Biológicas, UFMG, Av. Antônio Carlos 6.627, 31270-091 Belo Horizonte, MG, Brasil and Santa Casa de Misericórdia, Belo Horizonte, MG, Brasil **Departamento de Alimentos, Faculdade de Farmácia, UFMG, Belo Hozizonte, MG, Brasil

Schistosomicidal activity of alkylaminooctanethiosulfuric acids

The schistosomicidal activity of a new series of alkylaminooctanethiosulfuric acids was studied in white Swiss mice infected with the L.E. strain of Schistosoma mansoni (Belo Horizonte, MG, Brazil). In a preliminary screening of six compounds, two derivatives - 2-[(1-methylpropyl)amino]-1-octanethiosulfuric acid and 2-[(1-methylethyl)-amino]-1-octanethiosulfuric acid - given orally in doses of 300 mg/kg/day for five consecutive days, caused interruption of the oviposition and the hepatic shift of more than 90% of the worms. Both compounds caused a significant reduction in worm burden and, interestingly, the female schistosomes were more susceptible. With the therapeutic schedule of two doses of 800 mg/kg over a 20 day interval, the death of almost all the females and about 50% of the males was observed. Female worms recovered from treated mice showed scattered vitteline glands. Results of in vitro experiments against different developmental stages of the parasite revealed the induction of paralysis and damage to the tegument membrane. The drugs presented no toxic effects on the animals.