Determination of rutin and narcissin in marigold extract and topical formulations by liquid chromatography: applicability in skin penetration studies

A chromatographic technique for determination of rutin and narcissin in marigold extract and topical formulations was developed and validated. The method shows linearity over the concentration range of 0.2 - 6.0 μg/mL of rutin (r = 0.9986) and 0.8 - 12.0 μg/mL of narcissin (r = 0.9951). The values obtained for precision and accuracy are in agreement with ICH guidelines. Both the formulation excipients and the porcine ear skin samples did not interfere with the flavonoids determination. The recovery of rutin and narcissin in skin samples added with marigold extract was 81.41% and 83.35%, respectively, which demonstrate the applicability of this method to perform skin penetration studies.

Leaf and root volatiles produced by tissue cultures of Alpinia zerumbet (pers.) Burtt & Smith under the influence of different plant growth regulators

Volatiles produced by plantlets of Alpinia zerumbet were obtained by means of simultaneous distillation-extraction (SDE). The effects of indole-3-acetic acid, kinetin, thidiazuron and 6-benzylaminopurine on leaf and root volatile composition obtained by tissue cultures were investigated. A higher content of b-pinene and a lower content of sabinene were observed in leaf volatile of plantlets cultured in control, IAA and IAA+ TDZ media, as compared with those of donor plants. In vitro conditions were favorable to increase caryophyllene content. Volatile compounds from the root were characterized mainly by camphene, fenchyl-acetate and bornyl acetate; which constitute about 60% of total volatile.

Estudo das condições de estocagem do bagaço de cana-de-açúcar por análise térmica

An evaluation was made of the properties of sugarcane bagasse during the storage process for subsequent burning in a boiler. Samples of bagasse were collected over a period of 150 days from the Caeté sugar mill (MG) at various points of the stockpile soon after the sugarcane was pressed to extract its juice, as well as from natural bagasse, dry and damp. Thermal analyses of the samples were carried out and the results indicated that, during the storage of bagasse, dry or damp, the biomass loses up to 32% of its calorific power, due to decomposition of the hemicellulose.

Seasonal variation of the major secondary metabolites present in the extract of Eremanthus mattogrossensis Less (Asteraceae: Vernonieae) leaves

The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado. Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H2O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.

Optimization of solvent mixtures for extraction from bark of Schinus terebinthifolius by a statistical mixture-design technique and development of a UV-Vis spectrophotometric method for analysis of total polyphenols in the extract

A statistical mixture-design technique was used to study the effects of different solvents and their mixtures on the yield, total polyphenol content, and antioxidant capacity of the crude extracts from the bark of Schinus terebinthifolius Raddi (Anacardiaceae). The experimental results and their response-surface models showed that ternary mixtures with equal portions of all the three solvents (water, ethanol and acetone) were better than the binary mixtures in generating crude extracts with the highest yield (22.04 ± 0.48%), total polyphenol content (29.39 ± 0.39%), and antioxidant capacity (6.38 ± 0.21). An analytical method was developed and validated for the determination of total polyphenols in the extracts. Optimal conditions for the various parameters in this analytical method, namely, the time for the chromophoric reaction to stabilize, wavelength of the absorption maxima to be monitored, the reference standard and the concentration of sodium carbonate were determined to be 5 min, 780 nm, pyrogallol, and 14.06% w v-1, respectively. UV-Vis spectrophotometric monitoring of the reaction under these conditions proved the method to be linear, specific, precise, accurate, reproducible, robust, and easy to perform.

HPLC-DAD based method for the quantification of flavonoids in the hydroethanolic extract of Tonina fluviatilis Aubl. (Eriocaulaceae) and their radical scavenging activity

This article describes the isolation and identification of flavonoids in the hydroethanolic extract of the aerial parts from Tonina fluviatilis and evaluation of their antiradical activity. A method based on HPLC-DAD was developed and validated for detecting and quantifying flavonoids in hydroethanolic extracts. The flavonoids identified and quantified in the extract were 6,7-dimethoxyquercetin-3-O-β-D-glucopyranoside (1), 6-hydroxy-7-methoxyquercetin-3-O-β-D-glucopyranoside (2), and 6-methoxyquercetin-3-O-β-D-glucopyranoside (3). The developed method presented good validation parameters, showing that the results obtained are consistent and can be used in ensuring the quantification of these constituents in the extracts. Compounds 2 and 3 showed strong antiradical activity when compared with the positive controls (quercetin and gallic acid).

Grape juice quality control by means of ¹H nmr spectroscopy and chemometric analyses

This work shows the application of ¹H NMR spectroscopy and chemometrics for quality control of grape juice. A wide range of quality assurance parameters were assessed by single ¹H NMR experiments acquired directly from juice. The investigation revealed that conditions and time of storage should be revised and indicated on all labels. The sterilization process of homemade grape juices was efficient, making it possible to store them for long periods without additives. Furthermore, chemometric analysis classified the best commercial grape juices to be similar to homemade grape juices, indicating that this approach can be used to determine the authenticity after adulteration.

Problemas na premunização de melancia para o controle do mosaico causado pelo Papaya ringspot virus

Neste trabalho estudou-se a proteção de melancia (Citrullus lanatus) com estirpes fracas do Papaya ringspot virus, estirpe melancia, em condições de casa de vegetação e em campo. Os resultados mostraram que a proteção foi eficiente em ambos os testes. Nos testes em campo porém, as plantas protegidas da cultivar Crimson Sweet tiveram uma redução no peso médio de frutos por planta de, aproximadamente, 50% e 10,8%, em comparação às plantas não protegidas que estavam sadias, no primeiro e no segundo teste, respectivamente. O mesmo fato ocorreu com a cultivar Crimson Tide, na qual se registrou uma redução de 36,4%, aproximadamente, em um único teste. Além da redução na produção, outro problema encontrado na premunização da melancia foi a necessidade de duas inoculações sucessivas das mudas, em dias consecutivos, para aumentar a freqüência de plantas infetadas.

Epidemiology of apple leaf spot

Apple leaf spot (ALS) caused by Colletotrichum spp. is a major disease of apple (Malus domestica) in Southern Brazil. The epidemiology of this disease was studied in experiments carried out in the counties of Passo Fundo and Vacaria, State of Rio Grande do Sul, from February 1998 to October 2000. The disease was found in all the six apple orchards sampled in the growing seasons of 1997/98 and 1998/99. The fungus isolates associated with ALS fit the characteristics of C. gloeosporioides (75%), C. acutatum (8%), and Colletotrichum sp. (17%). The pathogen overwintered in dormant buds and twigs but not in dropped leaves or fruit mummies. Two sprays of copper oxychloride (at 0.3%) reduced the fungus initial inoculum by 65-84.6% in buds and 85.6-93.7% in twigs, but had no effect on the early season progress of the disease. Disease severity increased proportionally to elevation of temperature from 14 to 26-28 °C. At 34 °C, however, infection was completely inhibited. The duration of leaf wetness required for infection ranged from two hours at 30 °C to 32 h at 16 °C. The relationship of temperature (T) and leaf wetness (W) to disease severity (Y) was represented by the model equation Y = 0.00145[((T-13)1.78)((34.01-T )1.09)] * 25/[1+14 exp(-0.137W)], R² = 0.73 and P < 0.0001. Currently, this information is being used to manage the disease and to validate a forecast system for ALS.

Effect of population densities of Heterodera glycines race 3 on leaf area, photosynthesis and yield of soybean

The effect of Heterodera glycines on photosynthesis, leaf area and yield of soybean (Glycine max) was studied in two experiments carried out under greenhouse condition. Soybean seeds were sown in 1.5 l (Experiment 1) or 5.0 l (Experiment 2) clay pots filled with a mixture of field soil + sand (1:1) sterilized with methyl bromide. Eight days after sowing, seedlings were thinned to one per pot, and one day later inoculated with 0; 1.200; 3.600; 10.800; 32.400 or 97.200 J2 juveniles of H. glycines. Experiment 1 was carried out during the first 45 days of the inoculation while Experiment 2 was conducted during the whole cycle of the crop. Measurements of photosynthetic rate, stomatic conductance, chlorophyll fluorescence, leaf color, leaf area, and chlorophyll leaf content were taken at ten-day intervals throughout the experiments. Data on fresh root weight, top dry weight, grain yield, number of eggs/gram of roots, and nematode reproduction factor were obtained at the end of the trials. Each treatment was replicated ten times. There was a marked reduction in both photosynthetic rate and chlorophyll content, as well as an evident yellowing of the leaves of the infected plants. Even at the lowest Pi, the effects of H. glycines on the top dry weight or grain yield were quite severe. Despite the parasitism, soybean yield was highly correlated with the integrated leaf area and, accordingly, the use of this parameter was suggested for the design of potential damage prediction models that include physiological aspects of nematode-diseased plants.

Mycovellosiella robbsii sp. nov. causing leaf-spot on Mimosa caesalpiniaefolia

This is a description of the new species Mycovellosiella robsii, a cercosporoidal hyphomycete, associated with leaf spots on Mimosa caesalpiniaefolia, an important hedge plant with multiple uses in Brazil. The new species was compared to other cercosporoid species associated with plants of the genus Mimosa and other species of the genus Mycovellosiella described on legumes, and is recognized as a distinct taxon. Koch's postulates were carried out and the disease was reproduced by inoculating healthy plants with mycelial suspension or disk, confirming the pathogenicity. This is the first report of a fungal disease on this host.

Comparação da seqüência de nucleotídeos do gene da proteína capsidial de estirpes severas e premunizantes do Papaya ringspot virus

This study compared three mild and three severe strains of Papaya ringspot virus - type W (PRSV-W), based on nucleotide and amino acid sequences of the capsid protein (CP) gene. The CP nucleotide sequences of the mild strains shared 98% to 100% identity. When compared to the severe strains the identity ranged from 93% to 95%, except in the case of PRSV-W-2R, which resulted from reversion of the mild strains PRSV-W-2. The CP sequence of the reverting strain showed 100% identity with the sequence of its parental strain. An insertion of six nucleotides in the core region of the CP gene, which reflected the addition of two amino acids (Asn and Asp) in the deduced sequence of the protein, was found in all mild strains. These sequence comparisons were used to design strain-specific primers that were used to specifically amplify regions for either the mild or severe strains.

Sugarcane yellow leaf virus infection leads to alterations in photosynthetic efficiency and carbohydrate accumulation in sugarcane leaves

Infection by Sugarcane yellow leaf virus (ScYLV) causes severe leaf symptoms in sugarcane (Saccharum spp.) hybrids, which indicate alterations in its photosynthetic apparatus. To gain an overview of the physiological status of infected plants, we evaluated chlorophyll a fluorescence and gas exchange assays, correlating the results with leaf metabolic surveys, i.e., photosynthetic pigments and carbohydrate contents. When compared to healthy plants, infected plants showed a reduction in potential quantum efficiency for photochemistry of photosystem (PSII) and alterations in the filling up of the plastoquinone (PQ) pool. They also showed reduction in the CO2 net exchange rates, probably as a consequence of impaired quantum yield. In addition, reductions were found in the contents of photosynthetic leaf pigments and in the ratio chlorophyll a/chlorophyll b (chla/chlb). Carbohydrate content in the leaves was increased as a secondary effect of the ScYLV infection. This article discusses the relation of virus replication and host defense responses with general alterations in the photosynthetic apparatus and in the metabolism of infected plants.