Navegando por Assunto "Atividade antibacteriana"

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Acesso aberto (Open Access)
Atividade antibacteriana de plantas medicinais frente á bactérias multirresistentes e a sua interação com drogas antimicrobianas
(Universidade Federal do Pará, 2012-08-28) SARAIVA, Rosa Márcia Corrêa; VIEIRA, José Maria dos Santos; http://lattes.cnpq.br/6807452375674442
Infection control of the multidrug-resistant microorganisms sometimes is ineffective even with the development of new antibiotics. Many herbal extracts have antimicrobial effects and may represent an alternative therapy for infectious diseases, mainly when associated with antibiotics of clinical use. The aim of this study was to evaluate the antibacterial activity of medicinal plants in multidrug-resistant microorganisms and their interaction with antimicrobial agents. We evaluate the antibacterial activity of plant extracts and fractions of Eleutherine plicata (“marupazinho”) Geissospermum vellosii (“pau-pereira”) and Portulaca pilosa (“amor-crescido”) against isolates of Oxacillin-Resistant Staphylococcus aureus (ORSA) and multi-resistant bacteria Pseudomonas aeruginosa, from human clinical isolates. Also we evaluate interaction of these plant extracts with antimicrobial agents of clinical use. The antibacterial activity was determined by disk diffusion on Mueller Hinton agar and the Minimum Inhibitory Concentration (MIC) by micro dilution plate technique using Muller Hinton broth as culture medium and 0.01% resazurin as a developer of bacterial growth. The extracts and fractions were tested at concentrations of 500, 250, 125, 62.5, 31.2 and 16.2 μg/mL dissolved in 10% DMSO. Plants E. plicata and G. vellosii demonstrated activity against ORSA isolates with MICs of 125 μg/mL, whereas P. pilosa had an effect on the isolates of P. aeruginosa with MIC of 250 μg/mL. There were 25% of synergism and only 5% of antagonism of all 120 plant and antimicrobial agents interaction tested. ORSA isolates had synergistic interaction with ciprofloxacin, clindamycin and vancomycin agents and with both plant derivatives of E. plicata and G. vellosii. The derivatives of P. pilosa potentiated the action of the aztreonam, cefepime and piperacillin + tazobactam agents compared to the isolates of P. aeruginosa multidrug-resistant. The results shows therapeutic potential of E. plicata, G. vellosii and P. pilosa in the control of bacterial infections involving multidrug-resistant phenotype (MDR) and its interaction with antibacterial agents may represent a new alternative in the therapy of these infections.
Acesso aberto (Open Access)
Atividade antibacteriana, antioxidante e citotóxica in vitro do extrato etanólico da entrecasca da planta Ouratea hexasperma (EEEOH) (A. St-Hil.) Baill var. Planchonii Engl
(Universidade Federal do Pará, 2015-09-17) COSTA, Glauber Vilhena da; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Ouratea hexasperma (Ochnacea), popularly known as "cerrado barbatimão" is a very common plant in the brazilian cerrado region and has been used for the treatment of microbial infections and inflammation. Therefore, this study aimed to evaluate the antioxidant activities, quantifying total flavonoid content (TFT), antibacterial and cytotoxicity of ethanol extract of the bark of Ouratea hexasperma (EEBOH) as well as perform their phytochemical characterization. The plant was collected in the state of Amapá, and then was held extraction of dry bark through the cold maceration with 96% ethanol solution in a 2: 8 (w/v) for 1 day, forming the EEBOH. The phytochemical characterization was performed by testing chromatic/precipitation tube and flavonoid content was measured by assay complexation with aluminum using quercetin as standard (40-0,62μg/mL), and the total antioxidant capacity by the spectrophotometric method discoloration radical ABTS•+ (2,2'azino-bis-3-etilbenzotiazolin 6-sulfonic acid) - TEAC. The antimicrobial activity of EEBOH was tested against gram-positive and gram-negative bacteria, using the microdilution techniques broth with staining by resazurin, to determine the Minimum Inhibitory Concentration (MIC), and grown in petri dish with subsequent count of colony forming units (CFU) for obtaining the Minimum Bactericidal Concentration (MBC). The evaluation of the cytotoxicity of EEEOH human peripheral blood leukocytes. Mononuclear peripheral blood cells incubated with different concentrations of the extract and without stimulation (negative control). The cytotoxicity of EEEOH were tested using human peripheral blood leukocyte, mononuclear cells, with different extract concentrations and without stimulation (negative control), and incubated and maintained at 37 ° C, 98% humidity and 5% CO2 for 24 hours, NO and MDA were read in an ELISA spectrophotometer and different optical readings. The primary EEBOH phytochemical analysis showed the presence of tannins, saponins and flavonoids. The TFT in the extract was 1467 ± 264μg equivalents quercetin/g EEBOH. The antioxidant capacity by TEAC method showed high antioxidant activity, with no difference in antioxidant capacity (TEAC) between those concentrations of the extract. The EEBOH showed good antibacterial activity, mainly against gram-positive bacteria. The cytotoxicity was obtained by linear regression concentration able to kill 50% of cells (CC 50%) whose amount was 2231,5mg/mL, confirming that the crude extract has low cytotoxicity against human leukocytes, under the conditions tested. In the production of NO and MDA it found that the EEOC was not able to induce NO production of the concentrations tested. As well, no increase MDA of concentration induces changes when compared to the negative control (RPMI), confirming the low in vitro cytotoxicity of the extract. Statistical analyzes were performed by ANOVA one way and Turkey. In concluded that the EEBOH have antibacterial, antioxidant and low cytotoxicity.
Acesso aberto (Open Access)
Atividade antimicrobiana do óleo essencial de Piper aduncum L. e seu componente, dilapiol, frente a Staphylococcus spp. multirresistentes
(Universidade Federal do Pará, 2012-08-31) BRAZÃO, Maria Angélica Bolini; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
The essential oil of Piper aduncum (EPO) and its main component, the dilapiol (76.5%), were evaluated for antibacterial activity against different strains of Staphylococcus spp. ATCC and multiresistant. For testing the antibacterial activity of EPO and dilapiol were determined Minimum Inhibitory Concentration (MIC) and minimum bactericidal concentration (MBC), the technique of microdilution and by counting Colony Forming Units (CFU) using concentrations of 250, 500 , 750 and 1000 μg/ml of EPO and concentrations of 100 and 1000 μg/ml dilapiol. The bacterial inoculum used was adjusted to 1x104 range from 0.5 Mc Farland. As a negative control inoculum was used along with Tween 20, solubilising the essential oil and dilapiol, and as positive control we used the chloramphenicol 0.05 mg/mL. These compounds were tested against strains of S. aureus ATCC 25923, S. epidermidis ATCC 12228, MRSA hospital, and S.epidermidis, S. lentus multiresistant nosocomial. The results showed that the EPO showed the MIC 90% of 500 μg/mL and MBC of 1000 μg/mL against S. aureus ATCC 25923, whose concentration of 500 μg/mL was able to inhibit 60% of bacterial growth. The strain MRSA, the EPO showed a small inhibition (10%) at a concentration of 750 μg/mL, being obtained in the MIC90% 1000 μg/mL. In S. epidermidis ATCC 12228, the OEPA showed antimicrobial activity with MIC90% at 500 μg/mL and MBC at 750 μg/mL. For the strain S. epidermidis multiresistant, the PEO was able to inhibit only 35% growth of this strain at a concentration of 750 μg/mL, but the value obtained in the MIC90% 1000 mg/mL. As for dilapiol, the compound showed antimicrobial activity against a strain of S. aureus ATCC 25923 at a concentration of 1000 μg/mL, 100% growth inhibiting (CBM). On the other hand, had no antimicrobial effect on MRSA strain nor S. lentus multiresistant. Furthermore, the dilapiol inhibited only 20% of the growth of S. epidermidis ATCC 12228 and S. epidermidis multiresistant concentration of 1000 μg/mL. Thus, the data show a moderate antibacterial activity of the essential oil, and the dilapiol showed weak in vitro antimicrobial activity.
Acesso aberto (Open Access)
Produção de compostos fenólicos a partir de células imobilizadas do líquen Parmotrema andinum (Müll. Arg.) Hale e avaliação de atividade antimicrobiana
(2012-03) NÓBREGA, Nadejda de Azevedo; RIBEIRO, Sheyla Mara de Almeida; PEREIRA, Eugênia Cristina; MARCELLI, Marcelo Pinto; MARTINS, Mônica Cristina Barroso; FALCÃO, Emerson Peter da Silva; GUSMÃO, Norma Buarque de; SILVA, Nicácio Henrique da
Hale and evaluation of antimicrobial activity). Secondary metabolites obtained from lichens should be carefully used by the pharmaceutical, cosmetic, textile and food industries because the extraction and isolation of these metabolites requires large amounts of biomass, which is not renewable due to how slow lichens grow. Nowadays, it is possible to obtain these substances either by tissue culture or cell and enzymatic immobilizations, from an in natura thallus, using a small amount of lichenous material. Therefore, this work aimed to investigate the production of phenolic compounds from Parmotrema andinum (Müll. Arg.) Hale immobilized cells, using sodium acetate as a precursor in the biosynthesis of phenols. Testing of antimicrobial activity with organic extracts of the in natura thallus, cell eluate and lecanoric acid isolated from P. andinum Hale showed antimicrobial activity against Gram-positive bacteria. Through biochromatographic assays, it was possible to associate the antibacterial activity to the lecanoric acid and to another unidentified substance. The substances produced by cell immobilization did not exhibit any inhibitory action against tested microorganisms.