Atividade antifúngica de extratos de plantas a Colletotrichum gloeosporioides

The present work aimed to evaluate the effect fungitoxic of plant extracts on the mycelial growth and on the spores germination of C. gloeosporioides. The plant extracts were obtained starting from dried ground plants, using water and ethilic alcohol as extractor. Twenty-two plant species were used to obtain the extracts. The extracts were tested by means of the incorporation of 20% (v/v) in PDA medium, before or after sterilization. The percentage of inhibition of the mycelial growth (PIM) was determined. Extract in the proportion of 50% was added to a spore suspension used to determine the percentage of inhibition of the spores germination (PIS). The hidroetanolic extracts provided larger PIM of C. gloeosporioides, while larger PIS was obtained with the aqueous extracts. Non autoclaved extracts was the most efficient in mycelial growth of C. gloeosporioides, even more than the autoclaved ones. Aqueous and hidroetanolic extracts of Momordica charantia and hidroetanolic extract of Eucalyptus citriodora provided higher PIM. Aqueous extracts of Luffa acutangula, Eucalyptus citriodora, Chenopodium ambrosioides, and Bauhinia, and hidroetanolic extracts of Ruta graveolens, Eucalyptus citriodora, Zingiber officinale and Chenopodium ambrosioides inhibited more than 90% of spores germination.

When cholesterol is not cholesterol: a note on the enzymatic determination of its concentration in model systems containing vegetable extracts

Background: Experimental evidences demonstrate that vegetable derived extracts inhibit cholesterol absorption in the gastrointestinal tract. To further explore the mechanisms behind, we modeled duodenal contents with several vegetable extracts. Results: By employing a widely used cholesterol quantification method based on a cholesterol oxidase-peroxidase coupled reaction we analyzed the effects on cholesterol partition. Evidenced interferences were analyzed by studying specific and unspecific inhibitors of cholesterol oxidase-peroxidase coupled reaction. Cholesterol was also quantified by LC/MS. We found a significant interference of diverse (cocoa and tea-derived) extracts over this method. The interference was strongly dependent on model matrix: while as in phosphate buffered saline, the development of unspecific fluorescence was inhibitable by catalase (but not by heat denaturation), suggesting vegetable extract derived H2O2 production, in bile-containing model systems, this interference also comprised cholesterol-oxidase inhibition. Several strategies, such as cholesterol standard addition and use of suitable blanks containing vegetable extracts were tested. When those failed, the use of a mass-spectrometry based chromatographic assay allowed quantification of cholesterol in models of duodenal contents in the presence of vegetable extracts. Conclusions: We propose that the use of cholesterol-oxidase and/or peroxidase based systems for cholesterol analyses in foodstuffs should be accurately monitored, as important interferences in all the components of the enzymatic chain were evident. The use of adequate controls, standard addition and finally, chromatographic analyses solve these issues.

Validation of an immunoassay method for the determination of traces of carbaryl in vegetable and fruit extracts by liquid chromatography with photodiode array and mass spectrometric detection

A competitive enzyme-linked immunosorbent assay (ELISA) method for carbaryl quantitation in crop extracts was validated by liquid chromatography (LC) with diode array detection (DAD). For this purpose, six crops (banana, carrot, green bean, orange, peach and potato) were chosen for recovery and reproducibility studies. The general sample preparation included extraction with methanol followed by liquid-liquid partitioning and clean-up on Celite-charcoal adsorbent column of the vegetable extracts. ELISA samples consisted of a diluted LC extract in assay phosphate buffer (pH 7.5). The potential effect of methanol in these samples was evaluated. It was observed that a maximum content of 10% methanol present in the assay buffer could be tolerated without expressive losses in the ELISA performance. Under these conditions, a IC50 similar to 1.48 mu g l(-1) was obtained. A minimum matrix effect with a 1:50 dilution of the methanolic extracts in assay buffer was noticed, except for green bean samples that inhibited completely the assay. For the vegetable extracts, the ELISA sensitivities varied from 3.9 to 5.7 mu g l(-1), and good recoveries (82-96%) with R.S.D.s ranging from 5.7 to 12.1% were found. An excellent correlation between the LC-DAD and ELISA techniques was obtained. The confirmation of the carbaryl in less concentrated samples was achieved by LC-mass spectrometry interfaced with atmospheric pressure chemical ionisation. The [M + H](+)= 202 and [M + H-57](+)=145 ions, equivalent to the protonated molecular and l-naphthol ions, respectively, were used to carbaryl identification in these samples. (C) 1998 Elsevier B.V. B.V. All rights reserved.

Sweet Basil (Ocimum basilicum) Extracts Obtained by Supercritical Fluid Extraction (SFE): Global Yields, Chemical Composition, Antioxidant Activity, and Estimation of the Cost of Manufacturing

In this work, supercritical technology was used to obtain extracts from Ocimum basilicum (sweet basil) with CO(2) and the cosolvent H(2)O at 1, 10, and 20% (w/w). The raw material was obtained from hydroponic cultivation. The extract`s global yield isotherms, chemical compositions, antioxidant activity, and cost of manufacturing were determined. The extraction assays were done for pressures of 10 to 30 MPa at 303 to 323 K. The identification of the compounds present in the extracts was made by GC-MS and ESI-MS. The antioxidant activity of extracts was determined using the coupled reaction of beta-carotene and linolenic acid. At 1% of cosolvent, the largest global yield was obtained at 10 MPa and 303 K (2%, dry basis-d.b.); at 10% of cosolvent the largest global yield was obtained at 10 and 15 MPa (11%, d.b.), and at 20% of cosolvent the largest global yield was detected at 30 MPa and 303 K (24%, d.b.). The main components identified in the extracts were eugenol, germacrene-D, epi-alpha-cadinol, malic acid, tartaric acid, ramnose, caffeic acid, quinic acid, kaempferol, caffeoylquinic acid, and kaempferol 3-O-glucoside. Sweet basil extracts exhibited high antioxidant activity compared to beta-carotene. Three types of SFE extracts from sweet basil were produced, for which the estimated cost of manufacturing (class 5 type) varied from US$ 47.96 to US$ 1,049.58 per kilogram of dry extract.

Bioactivity of plant extracts on the larval and pupal stages of Aedes aegypti (Diptera, Culicidea)

Introduction Aedes aegypti is responsible for the transmission of the dengue and yellow fever viruses. This study evaluated the effects of extracts from Cnidosculos phyllacanthus, Ricinus communis, and Coutarea hexandra on the developmental periods of A.aegypti larvae and pupae. Crude extracts of C. phyllacanthus and C. hexandra and oil from R. communis and C. phyllacanthus were used. Methods Bioassays of the larvicidal and pupicidal effects of these products at different concentrations and times of exposure were evaluated. The lethal and sublethal effects were determined using different concentrations in larvicidal tests. Mortality data were evaluated by Probit analysis to determine the LC50 and LC90 values. Results The vegetable oils from C. phyllacanthus and R. communis demonstrated greater efficiency for larval control with an LC50=0.28µl/mL and an LC90=1.48µl/mL and LC50=0.029µl/mL and a LC90=0.26µl/mL, respectively. In pupal tests toxic effects for all insects were verified after exposure to the products at significant LC50 and LC90 values for 24 and 48h. The effects of sublethal concentrations of C. phyllacanthus (oil) were more effective on the insects. Conclusions The vegetables oils from C. phyllacanthus and R. communis demonstrated greater potential from the control of different developmental periods in the life cycle of this insect.

Water extracts of cabbage and kale inhibit ex vivo H2O2-induced DNA damage but not rat hepatocarcinogenesis

The chemopreventive potential of water extracts of the Brassica vegetables cabbage and kale was evaluated by administering their aqueous extracts in drinking water ad libitum to Wistar rats submitted to Ito’s hepatocarcinogenesis model (CB group and K group, respectively - 14 rats per group). Animals submitted to this same model and treated with water were used as controls (W group - 15 rats). Treatment with the vegetable extracts did not inhibit (P > 0.05) placental glutathione S-transferase-positive preneoplastic lesions (PNL). The number of apoptotic bodies did not differ (P > 0.05) among the experimental groups. Ex vivo hydrogen peroxide treatment of rat livers resulted in lower (P < 0.05) DNA strand breakage in cabbage- (107.6 ± 7.8 µm) and kale- (110.8 ± 10.0 µm) treated animals compared with control (120.9 ± 12.7 µm), as evaluated by the single cell gel (comet) assay. Treatment with cabbage (2 ± 0.3 µg/g) or kale (4 ± 0.2 µg/g) resulted in increased (P < 0.05) hepatic lutein concentration compared with control (0.5 ± 0.07 µg/g). Despite the absence of inhibitory effects of cabbage and kale aqueous extracts on PNL, these Brassica vegetables presented protection against DNA damage, an effect possibly related to increased hepatic lutein concentrations. However, it must be pointed out that the cause-effect relationship between lutein levels and protection is hypothetical and remains to be demonstrated.

Antioxidant potential of oregano (Oreganum vulgare L.), basil (Ocimum basilicum L.) and thyme (Thymus vulgaris L.): application of oleoresins in vegetable oil

Studies have been carried out in order to increase the stability of vegetable oils due to economic and health protection reasons. There is a growing interest in the addition of natural antioxidants; especially herbs and spices. For this reason, this study aimed at evaluating the antioxidant potential of the oleoresins of oregano, basil, and thyme, as well as their behavior when applied to soybean oil under various concentrations. Firstly, the antioxidant activity was determined by the β-carotene/linoleic acid system and by the quantification of total phenolic compounds. Next, different concentrations of oleoresins (500 to 3000 mg.kg-1) were added to the soybean oil, and its antioxidant potential was analyzed using the oxidative stability through a Rancimat equipment. The value of 3000 mg.kg-1 of thyme and oregano oleoresins was the concentration that presented the greatest oxidative stability to soybean oil making them a natural alternative to vegetable oil conservation.

Cheesemaking with vegetable coagulants - the use of Cynara L. for the production of ovine milk cheeses

This paper reviews the use of plant extracts as vegetable coagulants for cheesemaking. It covers the plants used as sources of coagulants, with a historical overview and particular emphasis on Cynara species. The genus Cynara L., its composition, milk clotting and proteolytic enzymes (cardosins) and their specificity towards peptide linkages are also described. Cheeses produced in the Iberian Peninsula using Cynara L. as coagulant are documented. Cynara L. is still the most used vegetable coagulant in cheesemaking, and also the most investigated. However, much work remains to be done to understand its action during cheese maturation and further characterization.

Characterization of the phytochemicals and antioxidant properties of extracts from Teaw (Cratoxylum formosum Dyer)

The leaves of the Thai vegetable, Teaw (Cratoxylum formosum Dyer) were extracted with ethanol to provide an extract that had antioxidant properties. The composition of the extract was studied by high-performance liquid chromatography with a diode array detector, and by electrospray ionization mass spectrometry. The main antioxidant component (peak 1) was chlorogenic acid, which was present at 60% of the extract. Three minor components were present at 7%, 3% and 2%, and other components that were present at lower concentrations were also observed. Treatment of the Teaw extract with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH center dot) caused a similar reduction in peak area of 55.2-58.1% for chlorogenic acid and the three minor components, indicating that these components had common structural features. Component 2 was identified as dicaffeoylquinic acid, and compounds 3 and 4 were identified as ferulic acid derivatives. The radical-scavenging activity of the Teaw extract was compared with alpha-tocopherol, BHT and chlorogenic acid, using the DPPH center dot and 2,2'-azinobis (3-ethylbenzothialozinesulfonic acid) radical cation (ABTS(center dot+)) assays. The Teaw extract scavenged both free radicals more strongly than did a-tocopherol and BHT, and the activity of the extract was consistent with the concentration of chlorogenic acid that was present, confirming that this component is a major contributor to the antioxidant activity. The acute toxicity of the Teaw leaf extract was investigated in mice, and it was found that the LD50 of the extract was > 32 g/kg. Consequently, this plant is a promising source of a natural food antioxidant. (c) 2006 Elsevier Ltd. All rights reserved.

Persistence of anticancer activity in berry extracts after simulated gastrointestinal digestion and colonic fermentation.

Fruit and vegetable consumption is associated at the population level with a protective effect against colorectal cancer. Phenolic compounds, especially abundant in berries, are of interest due to their putative anticancer activity. After consumption, however, phenolic compounds are subject to digestive conditions within the gastrointestinal tract that alter their structures and potentially their function. However, the majority of phenolic compounds are not efficiently absorbed in the small intestine and a substantial portion pass into the colon. We characterized berry extracts (raspberries, strawberries, blackcurrants) produced by in vitro-simulated upper intestinal tract digestion and subsequent fecal fermentation. These extracts and selected individual colonic metabolites were then evaluated for their putative anticancer activities using in vitro models of colorectal cancer, representing the key stages of initiation, promotion and invasion. Over a physiologically-relevant dose range (0-50 µg/ml gallic acid equivalents), the digested and fermented extracts demonstrated significant anti-genotoxic, anti-mutagenic and anti-invasive activity on colonocytes. This work indicates that phenolic compounds from berries undergo considerable structural modifications during their passage through the gastrointestinal tract but their breakdown products and metabolites retain biological activity and can modulate cellular processes associated with colon cancer.

Anti-hemorrhagic Activity of Four Brazilian Vegetable Species Against Bothrops jararaca Venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemical composition and antioxidants potential of extracts of yellow melon seeds in Soybean oil

The aim of this work was to characterize the yellow melon seeds, hybrid variety, as for their proximate composition, and to evaluate the antioxidant potential of extracts of seed in soybean oil. The extract of melon seeds (EM), obtained by extraction using ethanol: water (95:5), was applied in soybean oil at three different concentrations (500; 750 and 1000 mg kg(-1)) and submitted to Shaal oven method at 60 degrees C for 20 days. Oil samples were evaluated for peroxic a value in periods of five days. The antioxidant activity of the extract was compared to the BHT (butyl-hydroxytoluene) activity. The melon seeds showed a high nutrition value, containing high percentages of lipids (25.2%), proteins (20.1%) and fiber (30.0%). All these treatments retarded lipid oxidation in soybean oil; however the natural extracts were less effective than BHT after 10 days in the oven. The antioxidant activities of different treatments tested in this study followed the order: BHT > EM 1000 mg kg(-1) = EM 750 mg kg(-1) > EM 500 mg kg(-1)> control.

Antioxidant potential of oregano (Oreganum vulgare L.), basil (Ocimum basilicum L.) and thyme (Thymus vulgaris L.): application of oleoresins in vegetable oil

Por razões econômicas e de proteção à saúde, pesquisas têm sido dirigidas para ampliar a estabilidade dos óleos vegetais. Existe uma tendência para a adição de antioxidantes naturais, em particular, um crescente interesse em ervas e especiarias. Desta forma, os objetivos deste trabalho foram avaliar o potencial antioxidante das oleorresinas de orégano, manjericão e tomilho e seu comportamento ao serem aplicadas ao óleo de soja em diferentes concentrações. Numa primeira etapa foi determinada a atividade antioxidante pelo sistema β-caroteno/ácido linoleico e a quantificação de compostos fenólicos totais. Posteriormente, foram adicionadas ao óleo de soja diferentes concentrações das oleorresinas (500 a 3000 mg.kg-1) e analisado seu potencial antioxidante por meio da estabilidade oxidativa utilizando o Rancimat. A concentração de 3000 mg.kg-1das oleorresinas de orégano e tomilho foi a que apresentou melhor estabilidade oxidativa ao óleo de soja, o que as tornam alternativa natural na conservação de óleos vegetais.

Screening and confirmation of PAHs in vegetable oil samples by use of supercritical fluid extraction in conjunction with liquid chromatography and fluorimetric detection

A fast, simple, non-destructive method for the direct screening of polycyclic aromatic hydrocarbons (PAHs) in vegetable oil samples is proposed. The method uses a supercritical fluid extraction (SFE) system coupled on-line with a fluorimetric detector to determine PAHs. This special assembly avoids the main problems encountered in the determination of PAHs in complex matrices such as vegetable oils. PAHs are selectively extracted by using silica gel in the thimble and cleaned up by passage through a C18 column. Interferences are preferentially retained by the silica gel during the SFE process while PAHs are adsorbed in the C18 column and the remainder of the matrix is sent to waste. Finally, the C18 column is purged to remove residual CO2 gas and adsorbed PAHs are recovered by desorption with a solvent. The extracts from positive samples are subsequently analyzed by liquid chromatography (LC) with fluorescence detection. The proposed method allows the confirmation of vegetable oil safety and hence provides a new tool for consumer protection. (C) 2004 Elsevier B.V. All rights reserved.