987 resultados para LEAVES
Resumo:
Leaves of Passiflora alata Curtis were characterized for their antioxidant capacity. Antioxidant analyses of DPPH, FRAP, ABTS, ORAC and phenolic compounds were made in three different extracts: aqueous, methanol/acetone and ethanol. Aqueous extract was found to be the best solvent for recovery of phenolic compounds and antioxidant activity, when compared with methanol/acetone and ethanol. To study the anti-inflammatory properties of this extract in experimental type 1 diabetes, NOD mice were divided into two groups: the P. alata group, treated with aqueous extract of P. alata Curtis, and a non-treated control group, followed by diabetes expression analysis. The consumption of aqueous extract and water ad libitum lasted 28 weeks. The treated-group presented a decrease in diabetes incidence, a low quantity of infiltrative cells in pancreatic islets and increased glutathione in the kidney and liver (p<0.05), when compared with the diabetic and non-diabetic control-groups. In conclusion, our results suggest that the consumption of aqueous extract of P. alata may be considered a good source of natural antioxidants and compounds found in its composition can act as anti-inflammatory agents, helping in the control of diabetes.
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The aim of this study was to evaluate the differential sensitivity of sugarcane genotypes to H2O2 in root medium. As a hypothesis, the drought tolerant genotype would be able to minimize the oxidative damage and maintain the water transport from roots to shoots, reducing the negative effects on photosynthesis. The sugarcane genotypes IACSP94-2094 (drought tolerant) and IACSP94-2101 (drought sensitive) were grown in a growth chamber and exposed to three levels of H2O2 in nutrient solution: control; 3mmolL(-1) and 80mmolL(-1). Leaf gas exchange, photochemical activity, root hydraulic conductance (Lr) and antioxidant metabolism in both roots and leaves were evaluated after 15min of treatment with H2O2. Although, root hydraulic conductance, stomatal aperture, apparent electron transport rate and instantaneous carboxylation efficiency have been reduced by H2O2 in both genotypes, IACSP94-2094 presented higher values of those variables as compared to IACSP94-2101. There was a significant genotypic variation in relation to the physiological responses of sugarcane to increasing H2O2 in root tissues, being root changes associated with modifications in plant shoots. IACSP94-2094 presented a root antioxidant system more effective against H2O2 in root medium, regardless H2O2 concentration. Under low H2O2 concentration, water transport and leaf gas exchange of IACSP94-2094 were less affected as compared to IACSP94-2101. Under high H2O2 concentration, the lower sensitivity of IACSP94-2094 was associated with increases in superoxide dismutase activity in roots and leaves and increases in catalase activity in roots. In conclusion, we propose a general model of sugarcane reaction to H2O2, linking root and shoot physiological responses.
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Essential oil from the leaves of Guatteria australis was obtained by hydrodistillation, analyzed by Gas Chromatography coupled to Mass Spectromery (GC-MS) and their antiproliferative, antileishmanial, antibacterial, antifungal and antioxidant activities were also evaluated. Twenty-three compounds were identified among which germacrene B (50.66%), germacrene D (22.22%) and (E)-caryophyllene (8.99%) were the main compounds. The highest antiproliferative activity was observed against NCI-ADR/RES (TGI = 31.08 μg/ml) and HT-29 (TGI = 32.81 μg/ml) cell lines. It also showed good antileishmanial activity against Leishmania infantum (IC50 = 30.71 μg/ml). On the other hand, the oil exhibited a small effect against Staphylococcus aureus ATCC 6538, S. aureus ATCC 14458 and Escherichia coli ATCC 10799 (MIC = 250 μg/ml), as well as small antioxidant activity (457 μmol TE/g) assessed through ORACFL assay. These results represent the first report regarding chemical composition and bioactivity of G. australis essential oil.
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The aim of this work is to obtain, purify and characterize biochemically a peroxidase from Copaifera langsdorffii leaves (COP). COP was obtained by acetone precipitation followed by ion-exchange chromatography. Purification yielded 3.5% of peroxidase with the purification factor of 46.86. The COP optimum pH is 6.0 and the temperature is 35 ºC. COP was stable in the pH range of 4.5 to 9.3 and at temperatures below 50.0 ºC. The apparent Michaelis-Menten constants (Km) for guaiacol and H2O2 were 0.04 mM and 0.39 mM respectively. Enzyme turnover was 0.075 s-1 for guaiacol and 0.28 s-1 for hydrogen peroxide. Copaifera langsdorffii leaves showed to be a rich source of active peroxidase (COP) during the whole year. COP could replace HRP, the most used peroxidase, in analytical determinations and treatment of industrial effluents at low cost.
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The present paper reports results of the effect of Potato virus X (PVX) on the contents of total phenols and alkaloids in leaves of Datura stramonium. A significant decrease in the contents of phenols and alkaloids was observed in leaves inoculated with PVX (X-I). However, there was an increase in the percentage of phenols in leaves rubbed with phosphate buffer (C1-I) and in leaves from the nodes immediately above, possibly induced by mechanical injury. Gas chromatography/mass spectroscopy revealed amounts of scopolamine in samples submitted to all treatments, except X-I, in which the amount of this alkaloid was low. High amounts of an unidentified compound (molecular ion m/z 302 and a prominent peak at m/z 129) were noted in extracts from leaves X-I, C1-I and leaves from the nodes immediately above the leaves inoculated with PVX. It is suggested that the synthesis and accumulation of the unidentified compound is a result of stress from mechanical injury and virus inoculation.
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The extracts from leaves of Ocotea catharinensis Mez (Lauraceae) were found to contain fourteen neolignans and two sesquiterpenes: nine benzofuran types (including three new compounds 1e, 2f and 4b), one new seco-benzofuran type (3b), two bicyclo[3.2.1]octane types (including the new compound 5c), two new dimers of bicyclo[3.2.1]octane type (7a and 7b) and two sesquiterpenes (including a new humulanol 9). In addition, seven neolignans were also showed to occur in somatic embryos of O. catharinensis including one new bicyclo[3.2.1]octane type (4a).
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Croton macrobothrys Baill, Euphorbiaceae, is a tree from the Atlantic Forest in Southern Brazil, used in traditional medicine and popularly known as "dragon's blood" and "pau-sangue". Leaf n-hexane, dichloromethane and methanol extracts were analyzed by GC/MS and evaluated for their in vitro antiproliferative activity on cell lines 786-0 (kidney), HT-29 (colon), K562 (leukemia), NCI-ADR/RES (drug resistant ovary), NCI-H460 (lung), MCF-7 (mammary), PC-3 (prostate), OVCAR-3 (ovary), U251 (glioma) and UACC-62 (melanoma). The dicloromethane extract exhibited activity against all cell lines at the concentration 25 µg/mL, in particular on cell lines NCI-H460 (GI50 0.33 μg/mL) and K5662 (GI50 0.91 μg/mL). Relevant constituents in dichloromethane extract are the alkaloids corydine and salutaridine, as well as the diterpenes geranylgeraniol and crotonin-derived clerodanes.
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The aim of the present study was to evaluate the effect of soil characteristics (pH, macro- and micro-nutrients), environmental factors (temperature, humidity, period of the year and time of day of collection) and meteorological conditions (rain, sun, cloud and cloud/rain) on the flavonoid content of leaves of Passiflora incarnata L., Passifloraceae. The total flavonoid contents of leaf samples harvested from plants cultivated or collected under different conditions were quantified by high-performance liquid chromatography with ultraviolet detection (HPLC-UV/PAD). Chemometric treatment of the data by principal component (PCA) and hierarchic cluster analyses (HCA) showed that the samples did not present a specific classification in relation to the environmental and soil variables studied, and that the environmental variables were not significant in describing the data set. However, the levels of the elements Fe, B and Cu present in the soil showed an inverse correlation with the total flavonoid contents of the leaves of P. incarnata.
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The essential oil of the leaves from Annona coriacea Mart., Annonaceae, was extracted by hydrodistillation in a Clevenger apparatus and analyzed by GC/MS and GC/FID. The oil yield was 0.05% m/m. Sixty compounds were identified, in a complex mixture of sesquiterpenes (76.7%), monoterpenes (20.0%) and other constituents (3.3%). Bicyclogermacrene was its major compound (39.8%) followed by other sesquiterpenes. Most of the monoterpenes were in low concentration (<1%). Only β-pinene and pseudolimonene presented the highest level of 1.6%. The volatile oil presented anti-leishmanial and trypanocidal activity against promastigotes of four species of Leishmania and trypomastigotes of Trypanosoma cruzi, showing to be more active against Leishmania (L.) chagasi (IC50 39.93 µ g/mL) (95% CI 28.00-56.95 µ g/mL).
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The objective of this study was to extract and concentrate calcium oxalate (CaOx) crystals from plant leaves that form the above mentioned crystals. The chemical and physical studies of CaOx from plant to be performed depend on an adequate amount of the crystals. The plant used in this study was croton (Codiaeum variegatum). The leaves were ground in a heavy duty blender and sieved through a 0.20 mm sieve. The suspension obtained was suspended in distilled water. The crystals were concentrated at the bottom of a test tube. The supernatant must be washed until it is free of plant pigments and other organic substances. Biogenic CaOx crystals have well-defined and sharp peaks, indicating very high crystallinity. Moreover, the CaOx crystals were not damaged during the extraction procedure, as can be seen on the scanning electron microscope images. The porposed method can be considered efficient to extract and concentrate biogenic calcium oxalate.
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Rumen fermentation and methane emission for eucalyptus (Eucalyptus citriodora) fresh leaves (FL) or residue leaves (RL), after essential oil extraction from eucalyptus leaves in comparison with alfalfa (Medicago sativa) hay, were investigated in vitro. Eucalyptus FL and RL were obtained from the Distillery Trees Barras Company, Torrinha City, Sao Paulo, Brazil. The semi-automatic system of gas production was used to measure gas production, methane emission and rumen fermentation after 24 h incubation in vitro. The results showed that the crude protein (CP) contents were 76.4, 78.1 and 181.9 g kg(-1) DM for eucalyptus FL, RL and alfalfa hay, respectively. The neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) were significantly lower in eucalyptus FL and RL than alfalfa hay. The Eucalyptus fresh and residue leaves were rich in total phenols (TP) and total tannins (TT) but had negligible content of condensed tannins (CT). There was significant reduction in cumulative gas production about 54 and 51% with eucalyptus FL and RL, respectively, compared with alfalfa hay. The methane emission (mL/g DM) was reduced (P<0.05) by 53 and 57% with eucalyptus FL and RL, respectively, but the reduction was 21 and 16% when expressed on truly digested organic matter basis. There were a decline (P<0.05) in true dry and organic matter degradation in vitro in eucalyptus FL and RL compared with alfalfa hay substrate. The partitioning factor values were higher (P<0.05) in eucalyptus FL and RL than alfalfa hay. There was no significant difference observed between eucalyptus FL, RL and alfalfa hay in protozoa count. It is concluded that the eucalyptus leaves have potential effect to mitigate CH4 production in vitro, which may be attributed to a decrease in fermentable substrate rather than to a direct effect on methanogenesis.
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The stomatal density and index in compressed leaves of Glossopteris communis from two different roof shales from the Lower Permian in Parana Basin, Brazil (Western Gondwana) have been investigated to test the possible relationship with modeled global changes in atmospheric CO(2) during the Phanerozoic. The obtained parameters show that the genus Glossopteris from the Cool Temperate biome can be used as CO(2) -proxy, despite the impossibility of being compared with living relatives or equivalents. When confronted with already published data for the Tropical Summer Wet biome, the present results confirm the detection of low levels of atmospheric CO(2) during the Early Permian, as predicted by the modeled curve. Nevertheless, the lower stomatal numbers detected at the climax of the coal interval (Faxinal Coalfield, Sakmarian) when compared to the higher ones obtained in leaves from a younger interval (Figueira Coalfield, Artinskian) could be attributed to temporarily high levels of atmospheric CO(2). Therefore, the occurrence of an extensive peat generating event at the southern part of the basin and subsequent greenhouse gases emissions from this environment may have been enough to reverse regionally and temporarily the reduction trend in atmospheric CO(2). Additionally, the Faxinal flora is preserved in a tonstein layer, which is a record of volcanic activity that could also cause a rise in atmospheric CO(2). During the Artinskian, the scarce generation of peat mires, as revealed by the occurrence of thin and discontinuous coal layers, and the lack of volcanism evidence would be insufficient to affect the general low CO(2) trend.
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This study investigated the composition and antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves of Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper solmsianum and Piper umbelata and fruits of P. cernuum and P. diospyrifolium. The essentials oils were analyzed by GC-MS and submitted of the antifungal activity tests. The essential oils of fruits from P. cernuum and leaves of P. crassinervium and P. solmsianum showed potential antifungal activity against C. sphaerospermum and C. cladosporioides. In addition, this is the first report of the composition of essential oils of fruits of P. cernuum and P. diospyrifolium.
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Chemical analysis carried out in leaves of 18 specimens of Piper aduncum L. (Piperaceae) occurring at Ripasa Reserve, Araraquara, SP, Brazil indicated two distinct populations when investigated over a period of 14 months (January 2000 to February 2001) and then submitted to cluster analysis. The two groups were characterized by accumulation of prenylated benzoic acids, chromenes and dihydrochalcone, respectively. A total of seven compounds were identified by HPLC analysis and compared with standards including two prenylated benzoic acid [aduncumene (1) and 3-(3'-7'-dimethyl-2'-6'-octadienyl)-4-methoxy-benzoic acid (5)], four chromenes [methyl 2,2-dimethyl-8-(3'-methyl-2'-butenyl)-2H-1-chromene-6-carboxylate (4), methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (2b), methyl 8-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate (3) and 2,2-dimethyl-2H-1-chromene-6-carboxylic acid (2a)] and one dihydrochalcone [2',6'-dihydroxy-4'-methoxy-dihydrochalcone (6)].
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A cyanobacterial mat colonizing the leaves of Eucalyptus grandis was determined to be responsible for serious damage affecting the growth and development of whole plants under the clonal hybrid nursery conditions. The dominant cyanobacterial species was isolated in BG-11 medium lacking a source of combined nitrogen and identified by cell morphology characters and molecular phylogenetic analysis (16S rRNA gene and cpcBA-IGS sequences). The isolated strain represents a novel species of the genus Brasilonema and is designated Brasilonema octagenarum strain UFV-E1. Thin sections of E. grandis leaves analyzed by light and electron microscopy showed that the B. octagenarum UFV-E1 filaments penetrate into the leaf mesophyll. The depth of infection and the mechanism by which the cyanobacterium invades leaf tissue were not determined. A major consequence of colonization by this cyanobacterium is a reduction in photosynthesis in the host since the cyanobacterial mats decrease the amount of light incident on leaf surfaces. Moreover, the cyanobacteria also interfere with stomatal gas exchange, decreasing CO2 assimilation. To our knowledge, this is the first report of an epiphytic cyanobacterial species causing damage to E. grandis leaves.