300 research outputs found
South America and East Asia : diversification of dependency?
No full textBibliografía: p. 259-262.Florencia Rubiolo
Quinolizidine alkaloids from Genista ephedroides
No full textAlkaloids retamine, anagyrine, lupanine, 17-oxoretamine, 12-α-hydroxylupanine were detected, along with four others unidentified compounds in the aerial parts of Genista ephedroides D.C
Genepolide, a Sesterpene Gamma-Lactone with a Novel Carbon Skeleton from Mountain Wormwood (Artemisia umbelliformis)
No full textThe sesterpene γ-lactone genepolide (5) has been isolated from a Swiss horticultural variety of mountain wormwood (Artemisia umbelliformis) developed as a thujones-free alternative to native Western Alps wormwoods for the production of liqueurs. Genepolide is the formal Diels-Alder adduct of the exomethylene-γ-lactone costunolide (2) and the diene myrcene (6), two poorly reactive partners in cycloaddition reactions, and its structure was elucidated through a combination of spectroscopic methods. An investigation on the thermal stability of mixtures of 2 and 6, as well as considerations on the sensitivity of 2 to Br0nsted and Lewis acids, suggests that 5 is a genuine natural product and that the Swiss chemotype of A. umbelliformis contains Diels-Alderase enzymatic activity that is lacking in native mountain wormwoods from Western Alps. Remarkable differences in thermal and acid-catalyzed reactions of the cyclodecadiene moiety of 2 and 5 suggest that quaternarization at C-11 has far-reaching effects on the reactivity of their homoconjugated medium-sized diene system. The wide occurrence of this structural motif in sesquiterpenoids makes this issue worth a systematic investigation
Advance in histochemistry, ultrastructure and secretion of glandular trichomes in Salvia dolomitica Codd.
No full textIn order to have better knowledge of African sages, we begun the study of some Salvia species (Serrato Valenti, 1997; Bisio et al., 1998; Bisio et al., 2001) belonging to the G species-group according to Hedge classification (1974). In the present work we examined the ultrastructure and the histochemistry of the glandular trichomes, and the essential oil and the exudate products of Salvia dolomitica Codd., a shrub, native of Transvaal, South Africa.
The leaves of S. dolomitica appeared covered by uniseriate non-glandular trichomes and glandular trichomes. The latter occurred as peltate and capitate (Bisio et al., 2001).
The histochemistry of peltate hairs evidenced a secretion with abundant hydrophobic substances, but also small quantities of hydrophilic substances (polysaccharides, flavonoids, phenols, essential oil, triterpenoids). The ultrastructural observations are consistent with the histochemical ones; indeed, the former showed abundant plastids and smooth endoplasmic reticulum (SER), typical organelles of lipophilic secreting cells, as observed in many other trichomes secreting lipophilic substances. SER can also be responsible for flavonoid secretion, as indicated also by Schopker et al. (1995).
Two types of capitate hairs, depending on the number of the secreting and stalk cells, were observed. The cytoplasm of type I presented numerous Golgi stacks, plastids and dilated ER, that are organelles respectively responsible for secretion of polysaccharides, terpenes and also flavonoids. Indeed, histochemical observations indicated a complex secretion, in which phenolic compounds, polysaccharides and terpenes were present. Also in type II trichomes the histochemical and ultrastructural observations indicated a complex secretion with phenolic compounds, polysaccharides and terpenes, but probably the release of secretion occurs in a different way and at a different time.
In S. dolomitica the essential oil was mainly constituted by monoterpene hydrocarbons, followed by oxigenated monoterpenes and sesquiterpene hydrocarbons. The main components of the oil were represented by substances that are often described for other Salvia species, 1,8-cyneol, limonene, -3-carene, -pinene and -caryophyllene.
The analysis of leaf surface extract identified abietane diterpenoids: carnosol and 7-methoxirosmanol suggesting that these products could be good taxonomic markers.
BISIO A, FONTANA N, ROMUSSI G, DE TOMMASI N. 1998. Pharmazie 53: 210-211.
BISIO A, ROMUSSI G, MALECI L, CORALLO A, ZAPPA E, PROFUMO P. 2001. 96°Congresso della Società Botanica Italiana – Varese 26-28 settembre 2001. 145.
HEDGE IC. 1974. Notes from the Royal Botanic Garden, Edinburgh. 33: 1-118.
SCHÖPKER H, KNEISEL M, BEERHUES L, ROBENEK H, WIERMANN R. 1995. Planta 196: 712-719.
SERRATO-VALENTI G, BISIO A, CORNARA L, CIARALLO G. 1997. Annals of Botany 79: 329-336
Chapter 10: Chemometrics: Basic principles and applications
No full textThis chapter will be devoted to chemometrics in the multivariate design of the experiments and in data treatment in gas chromatography. Basic principles will be given on the most commonly used approaches, along with applications in the field of one-dimensional and multidimensional gas chromatography. This chapter shows how suitable multivariate statistical methods can be of great support in specific food applications such as confirmation of authenticity, geographical origin, quality, evaluation of technological processes, and so on, exploiting its potential also in the omics field, such as "foodomics"
India como potencia media asiática: Entre el pragmatismo y el balance regional
No full textFil: Rubiolo, María Florencia. Universidad Nacional de Córdoba. Facultad de Ciencias Sociales; Argentina.Fil: Rubiolo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentina.Asia, the dynamic epicenter of contemporary economic power, has also become the primary stage for the consolidation of middle powers on the global scene. Countries such as South Korea, Indonesia, Thailand, Australia, and Saudi Arabia stand out as prominent examples of states that embody thisstatus.India, the world’s most populous country, is emerging as one of Asia’s foremost powers, driven by sustained economic growth that today positions it as the fifth-largest economy globally. The country is solidifying its role as a key player in international affairs, shaped by its socio-historical context, regional dynamics of competition and cooperation, and a fluctuating global order that directly impactsthe projection and configuration of its foreign policy.In this article, we analyze India’s foreign policy under the premise that, despite its undeniable material conditions—economic, demographic, and geographic—its foreign policy behavior continues to align with the status of a middle power. Beyond the declared ambitions of various officials in Modi’s administration, India’s actions maintain the stance of a global balancer, characteristic of middle-tier powers. Furthermore, despite the U.S. push to elevate India’s regional role, the prioritization of continuity, efforts to manage tensions with China, and the country’s persistent and multifaceted internal challenges continue to position India in a secondary role within the region’s strategic landscape.Asia, epicentro dinámico del poder económico contemporáneo, se ha convertido también en el principal espacio de consolidación de potencias medias a nivel global. Corea del Sur, Indonesia, Tailandia, Australia y Arabia Saudita son algunos de los Estados que hoy se identifican con este concepto. India, país con la mayor población del planeta, emerge como una de las principales potencias de Asia como consecuencia del sostenido crecimiento económico que la posiciona hoy como la quinta economía en el mundo1. El país se consolida en el escenario internacional como un actor complejo, moldeado por su contexto sociohistórico, las dinámicas regionales de competencia y cooperación, y un fluctuante orden global que impacta de forma directa en la proyección y configuración de su política exterior. La India se encuentra en una posición particular entre la plétora de potencias medias –se destaca por sus condiciones excepcionales– y las grandes potencias, status que aún es esquivo a Nueva Delhi. De acuerdo con Sridharan (2017, p. 56) “India no es ni una de las grandes potencias ni una potencia menor; pero es una que no se puede ignorar y, en este sentido, encaja en la definición más general de potencia media”. En el mismo sentido, Kukreja (2020) sostiene que, a pesar de su poderío militar y nuclear, no tiene capacidad de intervención militar global, no detenta un dominio decisivo de su propia región, ni capacidad de configuración del sistema económico o militar. No obstante, sus dimensiones, su ubicación geográf ica, su creciente centralidad en el Indo-Pacífico y su creciente peso económico la definen como una potencia media con proyección global, aunque sin status de gran potencia.info:eu-repo/semantics/acceptedVersionFil: Rubiolo, María Florencia. Universidad Nacional de Córdoba. Facultad de Ciencias Sociales; Argentina.Fil: Rubiolo, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentina
A whole pattern iterative refinement method for powder X-ray diffraction spectra of two-phase coherent alloys
No full textAn iterative refining method using FullProf software (Rietveld refinement) as a multi-input–output black-box with cyclic feedback is proposed in order to accurately measure the lattice misfit in two-phase coherent alloys. The method uses two X-ray diffraction spectra taken on the same powder sample. In addition, it requires the volumetric fraction of the phases and the size of the crystallite in the precipitated phase as derived from the measurements made by the transmission electron microscopy–energy dispersive spectroscopy technique. The measurement of the lattice misfit in a Fe2AlV-strengthened ferritic Fe76Al12V12 alloy is shown as an application of the method.Fil: Ferreirós, Pedro Antonio. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad Tecnológica Nacional. Facultad Regional General Pacheco; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rubiolo, Gerardo Hector. Universidad Nacional de San Martín. Instituto Sabato; Argentina. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Citral-containing essential oils as potential tyrosinase inhibitors: A bio-guided fractionation approach
No full textExcessive melanin production causes serious dermatological conditions as well as minor aesthetic problems (i.e., freckles and solar lentigo). The downregulation of tyrosinase is a widespread approach for the treatment of such disorders, and plant extracts have often proven to be valuable sources of tyrosinase inhibitors. Citral (a mixture of neral and geranial) is an important fragrance ingredient that has shown anti-tyrosinase potential. It is highly concentrated in the essential oils (EOs) of Cymbopogon schoenanthus (L.) Spreng., Litsea cubeba (Lour.) Pers., Melissa officinalis L., and Verbena officinalis L. However, only L. cubeba EO has been investigated for use as a potential skin-whitening agent. This work evaluates the in vitro tyrosinase inhibitory activity of these EOs and studies, using bio-assay oriented fractionation, whether their differing chemical compositions influence the overall EO inhibitory activities via possible synergistic, additive, and/or competitive interactions between EOs components. The inhibitory activity of C. schoenanthus EO and that of M. officinalis EOs, with negligible (+)-citronellal amounts, were in-line with their citral content. On the other hand, L. cubeba and V. officinalis EOs inhibited tyrosinase to considerably greater extents as they contained beta-myrcene, which contributed to the overall EO activities. Similar observations were made for M. officinalis EO, which bears high (+)-citronellal content which increased citral activity
Phytochemical and biomolecular analyses of four wild edible Carduus species from Sardinia.
No full textIntra-specific variation in the little-known Mediterranean plant Ptilostemon casabonae (L.) Greuter analysed through phytochemical and biomolecular markers
No full textPtilostemon casabonae (L.) Greuter is a Mediterranean endemism traditionally used for its health-giving properties. Little is known about this species, therefore this study provides additional information about the phytochemical and biomolecular patterns of this plant, to have a combined fingerprint as a taxonomic tool. Several P. casabonae specimens were therefore collected from three different sites, two from Sardinia (Italy) and one from Corsica and the hydroalcoholic extracts of their aerial parts were investigated through HPLC-PDA-MS/MS analysis to study the phenolic composition. Quercetin, luteolin, kaempferol, apigenin and diosmetin O-glycosides, and caffeoylquinic acid derivatives were found as main components. Samples from the three sites showed similar phenolic profiles, although statistical analyses highlighted some quantitative differences for several compounds. The biomolecular analysis included amplification and sequencing of ITS, 5S-rRNA-NTS and psbA regions. No difference was found in the nucleotides among the P. casabonae samples from different geographical origins; however, a comparison with other Ptilostemon species sequences from Genbank, revealed an interspecific variability of ITS and psbA regions.
The combination of the results of the phytochemical and biomolecular studies provide information on P. casabonae useful to depict this little-known plant, which can also be applied for future investigations and to obtain a fingerprint of it. Moreover, the stability of the phenolic profile within the species affords to identify a set of specialised metabolites useful for its chemotaxonomic characterization. At the same time, the stability of the biomolecular profile of P. casabonae, and the identification of sequences specific for this species, enables to identify useful biomolecular markers to distinguish it unequivocally
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