941 resultados para Yeast extract


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A crude aqueous extract of the leaves of the guava tree, Psidium guajava L. (Myrtaceae), were studied for antidiarrhoeal effects, to place one of its traditional medical uses. The extract induced a decrease in the propulsive movements of the intestinal contents in mice. These findings suggested that an aqueous extract of guava leaves may be used as an effective treatment for non-specific diarrhoea in folk medicine.

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The clastogenic effect of the A. populnea leaves extract was tested in vivo on bone marrow cells of Wistar rats by evaluating the induction of chromosome aberrations and micronuclei induction on polychromatic erythrocytes. The extract was administered by gavage at doses of 300, 600 and 900mg/kg body weight. Experimental and control animals were submitted to euthanasia 24 h after the treatment. Under the conditions used, A. populnea leaves extract did not induce decrease in mitotic index and did not induce a statistically significant increase in the mean number of micronucleated polychromatic erythrocytes or chromosome aberrations in the bone marrow cells of Wistar rats. © 2007 The Japan Mendel Society.

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Casearia sylvestris (Flacourtiaceae) is a plant which grows in wild and has been widely used in folk medicine. In this study, clastogenic/aneugenic properties of Casearia sylvestris crude ethanolic extract were evaluated using in vivo chromosomal aberrations (CAs) and micronucleus (MN) assays in rodents. The animals were treated by gavage with 3 concentrations of the extract: 150, 300 and 500 mg/kg body weight. Bone marrow cells from Wistar rats were collected 24 h after having been submitted to the MN and CAs test. Peripheral blood cells from Swiss mice were collected 48 and 72 h after having been submitted to the MN test. The results show that C. sylvestris extract does not induce a significant increase in mean values for micronucleated polychromatic erythrocytes (MNPCE) in Swiss mice and Wistar rats, or CAs in rat bone marrow cells, at the 3 tested doses, indicating that the extract showed no clastogenic/aneugenic effects on chromosomes of the rodent cells tested. © 2007 The Japan Mendel Society.

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Antifungal activity of natural products has been tested by adapting methods designed for synthetic drugs. In this study, two methods for the determination of antifungal activity of natural products, agar diffusion and broth microdilution, the CLSI reference methods for synthetic drugs, are compared and discussed. The microdilution method was more sensitive. The minimal inhibitory concentrations (MIC) of crude extracts, fractions and pure substances from different species of the plant families Piperaceae, Rubiaceae, Clusiaceae, Fabaceae and Lauraceae, from the Biota project, were determined. Antifungal activities against Candida albicans, C.krusei, C.parapsilosis and Cryptococcus neoformans were produced by several samples.

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This work was aimed at evaluating the antioxidant activity of rosemary extract added to soybean oil in thermoxidation conditions. Purified soybean oil, refined soybean oil and refined soybean oil containing 1,000 mg/kg rosemary extract were heated at 180°C. The oxidation of the samples was evaluated after 0, 2.5, 5, 7.5 and 10 hours of thermoxidation by means of oxidative stability determination, total polar compounds and conjugated dienes. The purified oil differed significantly from the refined oil, mainly in relation to oxidative stability due the removal of the natural antioxidants. Rosemary extract presented antioxidant effects at high temperatures. After 10 hours of heating, 1,000 mg/kg rosemary extract added to the refined soybean oil significantly increased the oil oxidative stability from 7.52 to 13.5 hours and decreased the formation of polymers and decomposing products measured through the polar rates from 17.35 to 7.99%. The build up of primary oxidation products gauged through diene rates also decreased from 1.61 to 0.80%. Rosemary extract could be recommended as an alternative antioxidant.

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Paracoccidioides brasiliensis is a dimorphic fungus that causes paracoccidioidomycosis, the most prevalent human deep mycosis in Latin America. The dimorphic transition from mycelium to yeast (M-Y) is triggered by a temperature shift from 25°C to 37°C and is critical for pathogenicity. Intracellular Ca 2+ levels increased in hyphae immediately after temperature-induced dimorphism. The chelation of Ca 2+ with extracellular (EGTA) or intracellular (BAPTA) calcium chelators inhibited temperature-induced dimorphism, whereas the addition of extracellular Ca 2+ accelerated dimorphism. The calcineurin inhibitor cyclosporine A (CsA), but not tacrolimus (FK506), effectively decreased cell growth, halted the M-Y transition that is associated with virulence, and caused aberrant growth morphologies for all forms of P. brasiliensis. The difference between CsA and FK506 was ascribed by the higher levels of cyclophilins contrasted to FKBPs, the intracellular drug targets required for calcineurin suppression. Chronic exposure to CsA abolished intracellular Ca 2+ homeostasis and decreased mRNA transcription of the CCH1 gene for the plasma membrane Ca 2+ channel in yeast-form cells. CsA had no detectable effect on multidrug resistance efflux pumps, while the effect of FK506 on rhodamine excretion was not correlated with the transition to yeast form. In this study, we present evidence that Ca 2+/calmodulin-dependent phosphatase calcineurin controls hyphal and yeast morphology, M-Y dimorphism, growth, and Ca 2+ homeostasis in P. brasiliensis and that CsA is an effective chemical block for thermodimorphism in this organism. The effects of calcineurin inhibitors on P. brasiliensis reinforce the therapeutic potential of these drugs in a combinatory approach with antifungal drugs to treat endemic paracoccidioidomycosis. Copyright © 2008, American Society for Microbiology. All Rights Reserved.

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The present study focuses on potential agents of chromoblastomycosis and other endemic diseases in the state of Paraná, Southern Brazil. Using a highly selective protocol for chaetothyrialean black yeasts and relatives, environmental samples from the living area of symptomatic patients were analysed. Additional strains were isolated from creosote-treated wood and hydrocarbon-polluted environments, as such polluted sites have been supposed to enhance black yeast prevalence. Isolates showed morphologies compatible with the traditional etiological agents of chromoblastomycosis, e.g. Fonsecaea pedrosoi and Phialophora verrucosa, and of agents of subcutaneous or systemic infections like Cladophialophora bantiana and Exophiala jeanselmei. Some agents of mild disease were indeed encountered. However, molecular analysis proved that most environmental strains differed from known etiologic agents of pronounced disease syndromes: they belonged to the same order, but mostly were undescribed species. Agents of chromoblastomycosis and systemic disease thus far are prevalent on the human host. The hydrocarbon-polluted environments yielded yet another spectrum of chaetothyrialean fungi. These observations are of great relevance because they allow us to distinguish between categories of opportunists, indicating possible differences in pathogenicity and virulence.

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The synergistic effect of lemon seed extract with tert-butylhydroquinone (TBHQ) in soybean oil subjected to thermoxidation by Rancimat was investigated, and the influence of these antioxidants on α-tocopherol degradation in thermoxidized soybean oil. Control, LSE (2,400 mg/kg Lemon Seed Extract), TBHQ (50 mg/kg), Mixture 1 (LSE + 50 mg/kg TBHQ) and Mixture 2 (LSE + 25 mg/kg TBHQ) were subjected to 180°C for 20 h. Samples were taken at time 0, 5, 10, 15 and 20 h intervals and analysed for oxidative stability and α-tocopherol content. LSE and Mixtures 1 and 2 showed the capacity of retarding lipid oxidation when added to soya oil and also contributed to α-tocopherol retention in oil heated at high temperatures. However, Mixtures 1 and 2 added to the oil presented a greater antioxidant power, consequently proving the antioxidants synergistic effect.

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The present study was designed to analyze the effects of the association between cinnamon extract and aerobic exercise on the glycemic control and serum lipid profile of diabetic rats. Fifty Wistar male rats divided into five groups: control (C), sedentary nondiabetic rats; diabetic (D), sedentary diabetic rats; diabetic cinnamon (DC), sedentary diabetic rats that received cinnamon extract; diabetic exercise (DE), sedentary diabetic rats subjected to physical training; and diabetic cinnamon exercise (DCE), diabetic rats that received cinnamon extract and were subjected to physical training. For the induction of diabetes, the rats received alloxan. The cinnamon was administered to once a day for four weeks. The groups performed swimming exercises for one hour each day with lead overloads (3% - 5% of b.w) for five days a week for four weeks. Body weight loss was lower in the DE group compared to the other diabetic groups. The basal serum glucose of all the diabetic groups was higher compared to the control group. Group D had higher serum cholesterol concentrations compared to the DE and DCE groups. The resting blood lactate in group D was higher than the resting blood lactate in the DC and DE groups. Aerobic exercise partially counteracted the diabetic effects on body weight, serum cholesterol and blood lactate concentrations. No additional beneficial effects of cinnamon extract and aerobic exercise were observed on the parameters studied.

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A synbiotic yoghurt based on a combination of soymilk and yacon water extract (from yacon root tubers) was developed as a novel food product fermented with a probiotic culture of Enterococcus faecium CRL 183 and Lactobacillus helveticus ssp jugurti 4l6. Response surface methodology (RSM) was used to optimize the independent variables soymilk protein concentration and percentage of yacon extract in the formulation through a Central Composite Rotatable Design (CCRD), consisting of a 22 factorial design with two levels (-1, +1), two central points (0) and four axial points (± a, 0) (0, ± α). The responses were assessed by consumer acceptance tests. The optimization indicated that a formulation with a soymilk protein concentration of 1.74g/L and 25.86% of yacon extract gave the best average values, 5.91 for the taste and 6.00 for the overall impression responses. The formulation with 40% of yacon extract and the same concentration of soymilk protein achieved similar acceptance values: taste (5.94) and overall impression (5.87), however, with the extra yacon, it probably had a greater content of prebiotic fructooligosaccharides. Consequently, both formulations may give useful functional foods, with sensory properties comparable with those of soy yoghurt (control formulation). Copyright © 2010 by New Century Health Publishers.

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This study aimed to stablish the efficacy of a multivitamin and polyminerals supplemented with Panax ginseng extract (Natus Gerin ®) on patients subjected to common physical or mental stress. Patients were randomly divided in two groups and underwent a thorough clinical examination. Group A received Natus Gerin ® capsules and B placebo capsules. Two capsules were taken daily during meals during four weeks. Mood and physical activity were evaluated through a questionnaire assessing quality of life. From the 176 patients enrolled, 17 were excluded due to voluntary withdrawal, 81 completed the study in group A and 78 in group B. The treatment with Natus Gerin ® increased the quality of life when compared to placebo. After 15 and 30 days, group A showed a significant increase in average scoring score from 1.78 to 3.78, and finally 5.32 points. The study has shown that the daily use of Natus Gerin ® can be effective in improving quality of life in patients suffering from physical and mental stress.

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This study examined the antioxidant activity of lyophilized rosemary extract added to soybean oil, subjected to thermoxidation conditions and also its synergistic effect with the synthetic antioxidant tertiary butylhydroquinone (TBHQ). Soybean oil samples with no antioxidant added (SO), 3,000mg/kg rosemary extract (RE), 50mg/kg TBHQ (TBHQ), and a mixture of those two antioxidants (RE+TBHQ) were heated to 180C for 20h. After 0, 10 and 20h, the oxidative stability, total polar compounds, tocopherol content and fatty acid profile were determined. The addition of rosemary extract increased oxidative stability and resulted in a lower formation of total polar compounds and a higher retention of tocopherols. The RE treatment showed the highest amount of polyunsaturated fatty acids after 20h. There was not any synergy between TBHQ and rosemary extract in preventing oxidation of soybean oil. Rosemary extract showed a higher antioxidant potential when compared with TBHQ. PRACTICAL APPLICATIONS: Antioxidants are important ingredients in food processing because they have the capacity to protect foods, containing oils and fats, from damage caused by free radicals and reactive oxygen species. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants. Several species are used in cooking, medicine and by the pharmaceutical industry, standing out the rosemary. Being rich in compounds with high antioxidant activity, the rosemary extract can be used to replace synthetic antioxidants used in vegetable oils. © 2012 Wiley Periodicals, Inc.

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Secondary compounds produced by plants are considered an alternative method of weed suppression but can cause negative effects on crops in succession, especially in a no-tillage system, due to the degradation of crop residues with allelopathic potential. The objective of this work was to analyze the influence of foliar aqueous extracts of Brassica napus on the germination and initial development of seedlings of Phaseolus vulgaris. The extract was prepared as a stock 10 % weight/volume solution, and diluted into treatments of relative concentrations of 100 % (i.e. 10 % w/v stock), 75 %, 50 %, 25 % and 0 % (untreated control consisting of distilled water), in a completely randomized design. The seeds of Phaseolus vulgaris were moistened with the differing concentrated extracts and kept in a germination chamber at 25 °C, with a photoperiod of 12 h for nine days. The variables evaluated were: percentage germinating, first count of germination and germination velocity index, as well the root and hypocotyl length, and fresh and dry mass of the seedlings. The aqueous leaf extracts of Brassica napus did not influence the germination of Phaseolus vulgaris seeds, but did induce the growth of abnormal seedlings by inhibition of secondary roots and reduced prominence of the primary root.

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The results of the present study showed a significant decrease in the number of E. coli in root canals (first collection) after irrigation with castor oil extract during biomechanical preparation. All medications tested in this study were able to eliminate E. coli in root canals; however, they could not neutralize endotoxins completely.

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Flavonoids have been widely incorporated into cosmetic and dermatological formulations, affording benefits such as antioxidant action, improved skin tone and fewer lines and wrinkles. Brazil has a huge biodiversity, with one of the richest flora in the world, and existing studies justify the quest for greater research efforts in this area. The cajazeira (Spondias lutea L.), a plant of the Anacardiaceae family from tropical America, is widely disseminated in Brazil. This plant was chosen because of the presence of flavonoids that exhibit antioxidant activity. The purpose of this research was to develop a stable topical formulation containing Spondias lutea extract with the aim of preventing skin diseases caused by UV radiation. Hydro ethanolic extract of Spondias lutea fruit was prepared and assayed for its the flavonoids content. The antioxidant activity was estimated by DPPH and superoxide assay. The physicochemical stability and skin permeation of the cream containing 8% (w/w) of extract were assessed. The results showed that the S. lutea extract possessed antioxidant activity, and that it is possible to obtain a stable cosmetic containing the extract, which is able to penetrate the skin. Thus, it is possible to use this extract to produce an anti-aging cosmetic.