The relevance of oxidative stress in the pathogenesis of several diseases (including inflammatory disorders) has traditionally led to the search for new sources of antioxidant compounds. In this ...work, we report the selection of fractions with high antioxidant action from
(BT) leaf extracts.
methods (DPPH and ABTS assays; determination of phenolic and flavonoid contents) were used to select products derived from
with high antioxidant action. Then, the samples with the highest potentials were evaluated in a model of injury based on the inoculation of a lethal dose of heat-inactivated
in
larvae. Due to its higher antioxidant properties, the methanolic extract (BTME) was chosen to be fractionated using Sephadex LH-20 column-based chromatography. Two fractions from BTME (BTFC and BTFD) were the most active fractions. Pre-treatment with these fractions protected larvae of
from the stress induced by inoculation of heat-inactivated
. Similarly, BTFC and BTFD increased the lifespan of larvae infected with a lethal dose of enteroaggregative
042. NMR data indicated the presence of aliphatic compounds (terpenes, fatty acids, carbohydrates) and aromatic compounds (phenolic compounds). These findings suggested that products derived from
leaves are promising candidates for the development of antioxidant and anti-infective agents able to treat oxidative-related dysfunctions.
Context: Buchenavia tetraphylla (Aubl.) RA Howard (Combretaceae: Combretoideae) is an ethnomedicinal plant with reported antifungal action.
Objective: This study evaluates the antimicrobial activity ...of B. tetraphylla leaf extracts against clinical isolates of Candida albicans. The morphological alterations, combinatory effects with fluconazole and the cytotoxicity of the active extract were analyzed.
Materials and methods: Extracts were obtained using different solvents (hexane: BTHE; chloroform: BTCE; ethyl acetate: BTEE; and methanol: BTME). Antimicrobial activity was determined by the broth microdilution method using nine strains of C. albicans isolated from vaginal secretions and one standard strain (UFPEDA 1007).
Results: All extracts showed anti-C. albicans activity, including against the azole-resistant strains. The MIC values ranged from 156 to 2500 μg/mL for the BTHE; 156 to 1250 μg/mL for the BTCE; 625 to 1250 μg/mL for the BTME and 625 μg/mL to 2500 μg/mL for the BTEE. BTME showed the best anti-C. albicans activity. This extract demonstrated additive/synergistic interactions with fluconazole. Scanning electron microscopy analysis suggested that the BTME interferes with the cell division and development of C. albicans. BTME showed IC
50
values of 981 and 3935 μg/mL, against J774 macrophages and human erythrocytes, respectively. This extract also enhanced the production of nitric oxide by J774 macrophages.
Discussion and conclusion: Buchenavia tetraphylla methanolic extract (BTME) is a great source of antimicrobial compounds that are able to enhance the action of fluconazole against different C. albicans strains; this action seems related to inhibition of cell division.
This work aimed to study the effect of gamma radiation on the production of enzymes by filamentous fungi present in the seawater used for thermoelectric Termope S / A, in the vicinity of Port of ...Suape, Pernambuco. The isolated microorganisms were screened for their ability to produce enzymes. Subsequently, the fungi were irradiated at 3 doses (500, 1000 and 1500 Gy), using 4 inoculation techniques: lyophilisation, scraping of the spores, glass beads and agarose block. A fermentation assay for enzyme production was made in simple batch using a bioreactor New Brunswick, model Bioflo 110. The best enzyme produced was lignin peroxidase (676 U/L) by Aspergillus awamori in 500 Gy dose. Manganese peroxidase enzyme (1720 U / L), produced by three species of fungi (Penicillium sp.), was the highest in 500 Gy dose. Aspergillus terreus produced laccase enzyme (980 U/L) better in 500 Gy dose. In the assay of the fermentation bioreactor, the best results were found in BH-amid corn steep liquor, where 650 U/L of laccase was produced at the baseline and also in the medium containing corn steep liquor, where 620 U/L laccase was produced during 72 h. This is better than Sabouraud. The use of gamma radiation increased the production of enzymes by filamentous fungi compared to tests without radiation. Statistical analysis shows there are no significant differences between the inoculation techniques, and the best dose of radiation tested was 500 Gy. In trial bioreactor containing Bushnell Haas + corn steep, Penicillium sp. produced larger amounts of phenoloxidases enzymes compared to Sabouraud medium. Irradiation in a dose of 500 Gy stimulates A. awamori, A. terreus and Penicillium sp. to produce phenoloxidases enzymes.
Submitted by Romulus Lima (romulus.lima@ufpe.br) on 2015-03-12T17:46:46Z
No. of bitstreams: 2
DISSERTAÇÃO José Robson Neves Cavalcanti Filho.pdf: 853299 bytes, checksum: ...f5df497c46cc3c25f784a5b6906e7e46 (MD5)
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
Made available in DSpace on 2015-03-12T17:46:46Z (GMT). No. of bitstreams: 2
DISSERTAÇÃO José Robson Neves Cavalcanti Filho.pdf: 853299 bytes, checksum: f5df497c46cc3c25f784a5b6906e7e46 (MD5)
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
Previous issue date: 2014
A frequência de infecções fúngicas invasivas devido a fungos patógenos oportunistas aumentou claramente nos últimos anos, sendo Candida albicans responsável por grande parte dos casos. Esta levedura pode causar infecções superficiais de pele e mucosas, é a espécie mais encontrada nas infecções vaginais. Assim, é importante a busca de novas fontes de moléculas bioativas anti-C. albicans. Buchenavia tetraphylla (Combretaceae) é uma espécie neotropical, distribuída desde Cuba ao Rio de Janeiro, sendo uma planta etnomedicinal utilizada por comunidades tradicionais da região Nordeste do Brasil. Em pesquisa recente utilizando folhas da B. tetraphylla foi comprovada sua atividade antimicrobiana. O objetivo deste estudo foi avaliar a atividade antimicrobiana de extratos orgânicos de folhas de Buchenavia tetraphylla frente a Candida albicans, além de analisar o potencial citotóxico e antioxidante do extrato mais ativo. A triagem fitoquímica foi realizada por cromatografia em camada delgada, onde foram observada a presença de hidrocarbonetos, açúcares, glicosídeos, terpenos, taninos e flavonóides. A atividade antimicrobiana, foi determinada pelo método de microdiluição em caldo utilizando 10 linhagens de C. albicans. Os valores de CMI dos extratos variaram a partir de 0,15625 mg/mL a 2,5 mg/mL. Como o extrato metanólico apresentou melhor resultado anti-C. albicans, sua ação combinada com fluconazol foi testada sendo obsevado efeitos aditivos e sinérgicos. Nas células tratadas com o extrato metanólico no valor do CMI foram observadas modificações externas, apresentando maiores rachaduras e encolhimento celular que podem ser atribuído à perda do volume citosólico. Em relação a atividade hemolítica do mesmo extrato testado acima, foi observado um IC50 igual a 3,935 ±0,3088 mg/mL e para atividade antioxidante um IC50 de 64,66 (±1,81 μg/mL). Assim, estes resultados estimulam novas pesquisas sobre aspectos farmacológicos e citotóxicos dos extratos de B. tetraphylla a fim de apoiar a sua aplicação como agente antimicrobiano.
PDF
