959 resultados para R-br


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The variation in the proportion of reproductive branches, fruit, and seed production of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) were evaluated at ten beaches on Santa Catarina Island, state of Santa Catarina, Brazil. Three patches per beach of Ipomoea pes-caprae were monitored, involving two reproductive cycles. Ipomoea pes-caprae presented initially an average length of patches of 14 m, with 9.6 branches/m² and 39% of reproductive branches. The proportion of reproductive branches varied between the cycles, but there was not noticed an alternation of reproductive effort between the subsequent cycles. There was a reduction in the percentage of reproductive branches at six localities. In four beaches where Ipomoea pes-caprae populations declined, occurred reduction in the reproductive vigor, and in the seed production, being these declines associated to strong sea erosion. In another hand, in one beach with population increase, there were little reproductive branches due to the occurrence of young stolons. Four patches never maturated fruits, being three of these located at small beaches. The fruit and seed productions in the patches showed values up to 40 fruits/m² and up to 140 seeds/m², respectively. Populations with great seed production were localized in areas adjacent to great coastal plains, which may represent potential seed sources for areas with small seed production in the island.

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To determine the larvicidal activity of various extracts of Gymnema sylvestre against the Japanese Encephalitis vector, Culex tritaeniorynchus in Tamilnadu, India. To identify the active principle present in the promising fraction obtained in Chlorofom:Methanol extract of Fraction 2. The G. sylvestre leaf extracts were tested, employing WHO procedure against fourth instar larvae of C. tritaeniorhynchus and the larval mortalities were recorded at various concentrations (6.25, 12.5, 25.0, 50 and 100 µg/mL); the 24h LC50 values of the G. Sylvestre leaf extracts were determined following Probit analysis. It was noteworthy that treatment level 100 µg/mL exhibited highest mortality rates for the three different crude extracts and was significantly different from the mean mortalities recorded for the other concentrations. The LC50 values of 34.756 µg/mL (24.475-51.41), 31.351 µg/mL (20.634-47.043) and 28.577 µg/mL (25.159-32.308) were calculated for acetone, chloroform and methanol extract with the chi-square values of 10.301, 31.351 and 4.093 respectively. The present investigation proved that G. Sylvestre could be possibly utilized as an important component in the Vector Control Program.

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Calotropis procera R. Br. (Asclepiadaceae) is a well-known medicinal plant with leaves, roots, and bark being exploited by popular medicine to fight many human and animal diseases. This work deals with the fractionation of the crude latex produced by the green parts of the plant and aims to evaluate its toxic effects upon egg hatching and larval development of Aedes aegypti. The whole latex was shown to cause 100% mortality of 3rd instars within 5 min. It was fractionated into water-soluble dialyzable (DF) and non-dialyzable (NDF) rubber-free materials. Both fractions were partially effective to prevent egg hatching and most of individuals growing under experimental conditions died before reaching 2nd instars or stayed in 1st instars. Besides, the fractions were very toxic to 3rd instars causing 100% mortality within 24 h. When both fractions were submitted to heat-treatment the toxic effects were diminished considerably suggesting low thermostability of the toxic compounds. Polyacrylamide gel electrophoresis of both fractions and their newly fractionated peaks obtained through ion exchange chromatography or desalting attested the presence of proteins in both materials. When submitted to protease digestion prior to larvicidal assays NDF lost most of its toxicity but DF was still strongly active. It may be possible that the highly toxic effects of the whole latex from C. procera upon egg hatching and larvae development should be at least in part due to its protein content found in NDF. However the toxicity seems also to involve non protein molecules present in DF.

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Résumé A Madagascar, comme dans plusieurs pays en développement, une grande partie de la population utilise les plantes pour se soigner. Plusieurs espèces des plantes sont ainsi utilisées en médecine traditionnelle malgache. Par ailleurs, la plupart de ces plantes ne font l'objet que de très peu d'étude scientifique. En effet, dans le cadre de l'investigation phytochimique de plantes utilisées en médecine traditionnelle malgache et dans la recherche des nouvelles substances biologiquement actives, Hypoestes serpens (Vahl) R. Br. (Acanthaceae) a été étudiée. Elle se présente sous deux variétés (glabre et poilue) qui sont tous utilisées dans la région sud-centre de Madagascar pour traiter la blennorragie. De l'extrait dichlorométhanique des feuilles de H. serpens (Vahl) R. Br. variété glabre, 12 diterpénoides dont 8 nouveaux ont été isolés. Ils ont tous montré une activité antifongique contre un champignon pathogène des plantes, Cladosporium cucumerinum, dans la bioautographie directe sur CCM. Quelques-uns ont également présenté une activité contre une levure saprophyte chez l'homme, Candida albicans et une activité inhibitrice de l'enzyme acétylcholinesterase. Les diterpènoïdes sont déjà considérés comme les principaux métabolites secondaires du genre Hypoestes. Le fractionnement de l'extrait méthanolique a conduit à l'isolement de 5 glycosides des flavonoïdes dont 4 sous formes C-g,lycosides qui n'ont jamais été identifiés dans la famille Acanthaceae. Ces flavonoïdes ont présenté une activité antiradicalaire contre le DPPH. Le fractionnement et la purification des extraits ont été effectués à l'aide des différentes techniques chromatographiques telles que la chromatographie sur colonne ouverte, la filtration sur gel, la chromatographie liquide à haute pression, la chromatographie liquide à moyenne pression et la chromatographie liquide à basse pression. Par ailleurs, les structures des composés isolés ont été élucidées par des techniques spectroscopiques (UV, MS, RMN) et de méthode chimique (hydrolyse acide). En plus de ces techniques, certaines méthodes physiques (cristallographie par rayons-X, mesure de rotation optique) ont été réalisées pour confirmer certaines structures. Comme l'espèce Hypoestes serpens (Vahl) R. Br. se présente en deux variétés, une étude comparative a été effectuée. Cette étude avait montré que ces deux variétés ont une activité biologique similaire. Finalement, une technique analytique couplée, HPLC-UV-APC1-MS a permis de montrer la présence de toutes les substances isolées de la variété glabre dans la variété poilue. Second résumé Depuis des milliers d'almées, l'homme utilise les plantes pour se soigner. De nos jours, même avec le développement de la médecine moderne, la phytothérapie reste toujours la forme des soins de santé abordable et accessible pour la majorité des populations rurales des pays en développement. En outre, les plantes médicinales constituent une source potentielle de molécules biologiquement actives pour les industries pharmaceutiques et actuellement, on estime que 25% des médicaments commercialisés dans le monde sont à base de plantes Dans le cadre de la recherche des nouvelles molécules à intérêt thérapeutique qui pourraient devenir un médicament ou un modèle de structure ("lead compound") pour le développement de nouveaux médicaments, nous avons fait une étude sur l'espèce, Hypoestes serpens (Vahl) R. Br, plante utilisée en médecine traditionnelle malgache. Cette espèce existe en deux variétés, une glabre et une autre poilue qui sont tous utilisées dans la région sud-centre de Madagascar pour traiter la blennorragie. Par ailleurs, les tradipraticiens utilisent de préférence la variété poilue. Dans la première partie de ce présent travail, une investigation phytochimique de H serpens, variété glabre (variété moins utilisée) a d'abord été effectuée afm d'isoler et d'identifier le maximum des molécules biologiquement actives qu'elle contient. De ce fait, 17 composés dont 8 nouveaux ont été isolés. Les potentiels d'activités thérapeutiques des substances isolées ont ensuite été dépistés sur les différents cibles suivants.: deux souches de champignons (Cladosporium cucumerinum et Candida albicans), l'enzyme acétylcholinesterase et le radical DPPH. La deuxième partie de ce travail a été consacrée sur l'étude comparative des deux variétés (glabre et poilue) de H. serpens à la fois sur le plan biologique et sur le plan phytochimique. A l'issue de cette comparaison, nous avons constaté que l'utilisation de ces deux variétés en médecine traditionnelle malgache n'est pas un hasard ; les deux variétés avaient présenté une activité biologique très remarquable et contiennent les mêmes substances actives. Ces résultats démontrent les potentiels thérapeutiques de H serpens en médecine traditionnelle malgache et pourraient également encourager les tradipraticiens à utiliser la variété glabre tout en protégeant la variété poilue qui est en voie de disparition actuellement. En bref, l'investigation phytochimique de H. serpens justifiée par l'isolement et l'identification de certains de ses principes actifs ouvre la voie aux recherches des médicaments d'origine naturelle. Abstract In Madagascar, as in many developing countries, most people use plants to cure. A large number of plant species are employed in Malagasy traditional medicine. Moreover, most of these plants have been subject only very little scientific study. As part of a phytochemical investigation of plants used in Malagasy traditional medicine and in the search for new biologically active substances, Hypoestes serpens (Vah1) R.Br. (Acanthaceae) was investigated. This species exists in two varieties (glabrous and hairy) which are used in the south-center part of Madagascar to treat gonorrhoea. From the dichloromethane extract of the leaves of H. serpens (Vah1) R. Br. glabrous variety, 12 diterpenoids 8 of which were new, were isolated. They showed antifungal activity against the plant pathogen Cladosporium cucumerinum, in the direct TLC bioautography. Some of them also had activity against the yeast Candida athicans and inhibited acetylcholinesterase. The diterpenes are considered as the principal secondary metabolites of the genus Hypoestes. Fractionation of the methanol extract led to the isolation of 5 flavonoid glycosides, 4 of which were C-glycosides, never before identified in the Acanthaceae family. These flavonoids showed radical scavenging activity against DPPH. The fractionation and the purification of the extracts were achieved by different chromatographic techniques such as open-column chromatography, gel filtration, high- pressure liquid chromatography, medium-pressure liquid chromatography and low-pressure liquid chromatography. Moreover, the structures of the isolated compounds were elucidated by spectroscopic techniques (UV, MS, NMR) and chemical technique (acid hydrolysis). In addition, some physical methods (X-ray crystallography, measurement of optical rotation) were performed to confirm some structures. As the species Hypoestes serpens (Vah1) R. Br. is present in two varieties, a comparative study was carried out. This study showed that these two varieties had similar biological activity. Finally, a coupled analytical technique HPLC-UV-APCI-MS showed the presence of the same compounds in both the glabrous and hairy varieties.

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This work had as objective verified the term-stability of the Soxhlet modified system with analytical and pharmacothecnical application in extractive processes of Nasturtium officinale. It has proven that the process is thermo-stable. The analysis with analytical have determined 3.606 mg g-1 in chlorogenic acid and 11.813 mg g-1 in rutin (extract 1:20 w/v) and with pharmacotecnical 3.427 mg g-1 in chlorogenic acid and 11.278 mg g-1 in rutin (extract 1:6 w/v). The income of the pharmacothecnical process was inferior to the analytical, suggesting that the pharmacothecnical process would need of at least the double of time in each extraction system.

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Among other applications, Ipomoea pes-caprae is popularly used to treat jellyfish stings, supporting the development of a product for dermatological use. Hydroethanolic spray-dried extract was chosen for the further development of phytomedicines, and a stability-indicative HPLC-UV method was developed and validated for the determination of isoquercitrin and isochlorogenic acids A, B and C. The method was developed using a C18 column (250 x 4.6 mm, 5 µm) with an acetonitrile:water mobile phase at pH 3.0 in a gradient run. The four constituents and other unidentified components of the extract were appropriately resolved without interference of degradation products after stress tests (acid, alkali, neutral, oxidant, photolysis). The method showed linearity in the isoquercitrin concentration range from 5.0-50.0 µg mL-1, with adequate precision (RSD% < 2.5% for the intra- and inter-day studies), accuracy (recovery of 100.0 ± 2.0%), and robustness. Both the herbal drug and spray-dried extract of I. pes-caprae were subjected to stability studies in accelerated and long-term conditions over four months. The samples maintained their characteristics and marker contents (< 10% of variation).

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Specimens of Leonotis nepetiflolia were obtained from cultivated and wild environments to verify their influences in chemical composition. Phytochemical analyses were conducted for the ethyl acetate phase obtained by partitioning the crude ethanol extract from the cultivated leaves of L. nepetifolia. In doing so, flavonoid 3',4',5-trimethoxy-6,7-dihidroxyflavone (cirsiliol), a chemotaxonomic marker of the family Lamiaceae, was isolated. The results reveal that all phases and extracts tested exhibited weak to moderate antimicrobial activity against the strains of bacteria tested. The evaluation of in vitrocytotoxic and antitumor activity showed that the ethyl acetate phases obtained from both wild and cultivated leaves exhibit high potential cytotoxic and antitumor (> 78.0% of inhibition) activity. The major component of these phases was identified by high-performance liquid chromatography-diode array detector and nuclear magnetic resonance analyses using both 1D and 2D methods. The results further indicate that the flavonoid cirsiliol is the agent responsible for the activity observed in these phases.

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Este trabalho teve como objetivo avaliar o comportamento da madeira de Grevillea robusta na produção de painéis de madeira aglomerada. Os painéis foram produzidos em densidades de 0,60 e 0,80 g/cm³ e conteúdo de resina de 6 e 8%. Os resultados de propriedades físicas e mecânicas dos painéis fabricados com densidade de 0,80 g/cm³ e conteúdo de resina de 8% evidenciaram que a madeira de Grevillea robusta pode ser utilizada como fonte alternativa de matéria-prima para produção de painéis aglomerados.

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As results of a revision of the Brazilian species of Ditassa, lectotypes for D. endoleuca Schltr., D. pauciflora Decne. and D. ramosa E. Fourn. (= D. blanchetii Decne.) are designated.

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Pearl millet flour was utilized in kibbeh formulations instead of whole-wheat flour. Physicochemical properties, oxidation stability and sensorial characteristics of control kibbeh made with whole-wheat flour (CT) were compared with kibbehs prepared with millet flour (roasted or wet) and stored for 90 days (–18 °C). Kibbeh prepared with millet flour presented good oxidation stability (TBARS concentration). Baked kibbehs (with roasted millet flour) presented good acceptability and kibbeh samples did not differ significantly (p > 0.05) from the whole-wheat flour sample, when global appearance, texture and flavor were evaluated. Millet flour could be a suitable ingredient for kibbeh formulations, maintaining their nutritional value and sensorial quality in addition to being a gluten-free product.

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This research work aimed at investigating the physiological mechanisms of tolerance of pearl millet to low soil Phosphorus availability and drought under the Sahelian conditions.

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O estudo taxonômico do gênero Eleocharis R. Br. para o Rio Grande do Sul foi desenvolvido através dos métodos tradicionais em taxonomia. Os dados foram obtidos através da bibliografia, revisão de herbários regionais e coleta de exemplares a campo. O gênero está representado no Rio Grande do Sul por 27 espécies: Eleocharis acutangula (Roxb.) Schult., E. bonariensis Nees, E. contracta Maury, E. dunensis Kük., E. elegans (Kunth) Roem. & Schult., E. filiculmis Kunth, E. flavescens (Poir.) Urb., E. geniculata (L.) Roem. & Schult., E. interstincta (Vahl) Roem. & Schult., E. loefgreniana Boeck., E. maculosa (Vahl) Roem. & Schult., E. minima Kunth var. minima, E. montana (Kunth) Roem. & Schult., E. montevidensis Kunth, E. nudipes (Kunth) Palla, E. obtusetrigona (Lindl. & Nees) Steud., E. ochrostachys Steud., E. parodii Barros, E. aff. quinquangularis, E. quinquangularis Boeck., E. rabenii Boeck., E. radicans (Poir.) Kunth, E. sellowiana Kunth, E. squamigera Svenson, E. subarticulata (Nees) Boeck., E. viridans Kük. e Eleocharis sp. O trabalho apresenta descrições, ilustrações, dados sobre distribuição geográfica, habitat e períodos de floração e frutificação das espécies, além de uma chave dicotômica para diferenciá-las.

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In this work we report the identification of two flavonol glycosides isolated from the leaves of Calotropis procera R. Br. (Asclepiadaceae), a plant species with large occurrence in Northwest of Brazil with some applications in folk medicine. Some proved pharmacological activities in this species could be attributed to the presence of flavonol glycosides. The extraction and isolation of flavonol glycosides was carried out firstly by a liquid-liquid partition, and then by elution of n-BuOH fraction with MeOH over a Sephadex LH-20 column. The identification of flavonol glycosides isorhamnetin-3-O-rutinoside (1), and isorhamnetin-3-O-robinobioside (2), was obtained by 1H and 13C NMR, one- and two-dimensional techniques.

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[ES] Se confirma la expansión corológica del xenófito, Maireana brevifolia (R.Br.) P.G. Wilson, especie invasora de reciente introducción en Gran Canaria comentándose su ecología y la amenaza que implica para las comunidades vegetales de los espacios naturales protegidos en la isla.