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Ganan N.A.,National University of Cordoba | Ganan N.A.,Institute Ciencia Y Tecnologia Of Los Alimentos Icta | Dambolena J.S.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Martini R.E.,National University of Cordoba | Bottini S.B.,National University of the South
Journal of Supercritical Fluids | Year: 2015

Low-menthol or dementholized oils can be regarded as potential sources of biocidal compounds, particularly monoterpenic ketones such as menthone, piperitone, piperitenone, pulegone and carvone. In this work, the recovery of piperitenone from peppermint oil by supercritical carbon dioxide fractionation is studied. Separation selectivity and gas loading measurements were performed in a semicontinuous high-pressure apparatus in order to evaluate the effect of temperature and solvent density on these properties. Semicontinuous fractionation was also carried out at a fixed temperature (313 K) and pressure (85 bar), collecting and analyzing extract samples until a purified piperitenone raffinate was obtained. The phase behavior of the system was modeled and predicted with the group contribution equation of state (GC-EOS). Good agreement with the experimental results was obtained. Finally, a continuous countercurrent multistage fractionation process was simulated, based on the GC-EOS model. The effect of operation temperature and pressure, solvent-to-feed ratio and reflux ratio was studied for different purity and recovery requirements and oil feed compositions. © 2014 Elsevier B.V. All rights reserved. Source


Oliva M.D.L.M.,National University of Rio Cuarto | Beltramino E.,National University of Rio Cuarto | Gallucci N.,National University of Rio Cuarto | Casero C.,National University of Rio Cuarto | And 2 more authors.
Boletin Latinoamericano y del Caribe de Plantas Medicinales y Aromaticas | Year: 2010

Essential oils are known to exert antimicrobial activity. Differences in the chemical composition of them influence this activity. This work intends to study the variability in the chemical composition and the antimicrobial activity of essential oils obtained from plants of A. triphylla collected from different regions of Argentina. Essential oils were obtained by hydrodistillation and analyzed with GC-MS. The antimicrobial studies were carried out by the paper disc diffusion method. The essential oils shared common components but presented differences in the quantity and quality of the rest of them. The essential oil from La Paz showed the highest citral/limonene relation and the best antimicrobial activity. Yeasts resulted to be the most sensitive microorganisms, followed by the Gram positive bacteria. Statistical analysis showed significative differences in the antimicrobial activity. The differences in the biological activity of each essential oil could be attributed to the quantity and quality of the terpenic composition. © 2010 The Authors. Source


Wilkinson A.,Lancaster University | Wilkinson A.,University of Manchester | Hill P.W.,Bangor University | Vaieretti M.V.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | And 4 more authors.
Ecology and Evolution | Year: 2015

In monoculture, certain plant species are able to preferentially utilize different nitrogen (N) forms, both inorganic and organic, including amino acids and peptides, thus forming fundamental niches based on the chemical form of N. Results from field studies, however, are inconsistent: Some showing that coexisting plant species predominantly utilize inorganic N, while others reveal distinct interspecies preferences for different N forms. As a result, the extent to which hypothetical niches are realized in nature remains unclear. Here, we used in situ stable isotope tracer techniques to test the idea, in temperate grassland, that niche partitioning of N based on chemical form is related to plant productivity and the relative availability of organic and inorganic N. We also tested in situ whether grassland plants vary in their ability to compete for, and utilize peptides, which have recently been shown to act as an N source for plants in strongly N-limited ecosystems. We hypothesized that plants would preferentially use NO3 --N and NH4 +-N over dissolved organic N in high-productivity grassland where inorganic N availability is high. On the other hand, in low-productivity grasslands, where the availability of dissolved inorganic N is low, and soil availability of dissolved organic N is greater, we predicted that plants would preferentially use N from amino acids and peptides, prior to microbial mineralization. Turves from two well-characterized grasslands of contrasting productivity and soil N availability were injected, in situ, with mixtures of 15N-labeled inorganic N (NO3 - and NH4 +) and 13C15N labeled amino acid (l-alanine) and peptide (l-tri-alanine). In order to measure rapid assimilation of these N forms by soil microbes and plants, the uptake of these substrates was traced within 2.5 hours into the shoots of the most abundant plant species, as well as roots and the soil microbial biomass. We found that, contrary to our hypothesis, the majority of plant species across both grasslands took up most N in the form of NH4 +, suggesting that inorganic N is their predominant N source. However, we did find that organic N was a source of N which could be utilized by plant species at both sites, and in the low-productivity grassland, plants were able to capture some tri-alanine-N directly. Although our findings did not support the hypothesis that differences in the availability of inorganic and organic N facilitate resource partitioning in grassland, they do support the emerging view that peptides represent a significant, but until now neglected, component of the terrestrial N cycle. This study used 15N-labelled NO3 - and NH4 + and 13C15N-labelled amino acid and peptide to test the idea, in temperate grassland, that niche partitioning of N based on chemical form is related to plant productivity and the availability of IN. We found NH4+ to be the predominant N source for the majority of plant species across both grasslands, although DON was an important source of N for plant species at both sites, and in the low productivity grassland, Luzula sp. were able to capture peptide-N directly. Although our findings did not support the hypothesis that differences in the availability of DIN and DON facilitate resource partitioning in grassland, they do support the emerging view that peptides represent a significant, but until now neglected, component of the terrestrial N cycle. © 2015 Published by John Wiley & Sons Ltd. Source


Fortunato R.H.,Instituto Nacional de Tecnologia Agropecuaria | Fortunato R.H.,CONICET | Fortunato R.H.,University of Moron | Robbiati F.O.,CONICET | Robbiati F.O.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv
Phytotaxa | Year: 2014

Rhynchosia sousae (Leguminosae, Papilionoideae) an endemic species from Veracruz State, in eastern Mexico, is described as new and illustrated. On account of its morphological features, it is assigned to sect. Rhynchosia. A table separating it from similar species: R. amabilis and R. precatoria, is presented, and its relationships and distinguishing characters are discussed. © 2014 Magnolia Press. Source


Robbiati F.O.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Robbiati F.O.,CONICET | Lamarque A.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Lamarque A.,National University of Cordoba | And 6 more authors.
Phytotaxa | Year: 2013

Multivariate and univariate analyses based on morphological characters and seed soluble protein electrophoretic profiles were carried out in order to understand the taxonomic status within the complex S. fabrisii-S. trichosepala. Twenty morphological characters from herbarium specimens were recorded and analyzed by ANOVA, principal component and cluster analysis. The seed protein electrophoretic analysis including cluster analysis was based on three populations: one of S. fabrisii and two of S. trichosepala. The results showed that both taxa differed only by three morphological features; in parallel, the CPA and CA demonstrate that no clearly separated group can be recognized. The seed protein electrophoretic profiles show a high degree of similarity. Based on these results, and due to the variability observed, the inclusion of S. fabrisii in the synonymy of S. trichosepala is proposed. © 2013 Magnolia Press. Source

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