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Search Results: 1 - 10 of 251 matches for " Phenols "
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Development and Characterization of Nanovesicles Containing Phenolic Compounds of Microalgae Spirulina Strain LEB-18 and Chlorella pyrenoidosa  [PDF]
Letícia Marques de Assis, Adriana Rodrigues Machado, Amanda de Souza da Motta, Jorge Alberto Vieira Costa, Leonor Almeida de Souza-Soares
Advances in Materials Physics and Chemistry (AMPC) , 2014, DOI: 10.4236/ampc.2014.41002
Abstract:

The objective of this study was to elaborate liposomes, through the lipid film hydration methodology, to nanoencapsulate phenolic compounds of Spirulina LEB-18 and Chlorella pyrenoidosa microalgae, and evaluate their physicochemical characteristics and storage stability for 21 days. The total phenolic compounds were evaluated using a calibration curve of gallic acid using methanol and ethanol as extraction solvents. The size and polydispersity index of nanovesicles were determined by light scattering and the percentage encapsulation efficiency was determined by a centrifugation process. The stability of the liposomes at storage time was measured by zeta potential for 21 days. The methanol extracts from Spirulina had a higher content of phenolic compounds (2.62 mg gallic acid·g-1 of microalgae) compared to the extracts of Chlorella. However, liposomes with ethanolic extracts of the two algae showed higher encapsulation efficiency. The value was higher (96.40%) for Chlorella. All samples obtained nanometric size, with the highest value obtained for the liposome containing ethanol extract of Chlorella (239 nm) differing significantly (p 0.05) from the others. The liposomes containing extracts of Spirulina were more stable during the 21 days of storage, whereas, those consisting of ethanol extract showed no significant difference

Fenóis halogenados e/ou sulfatados de macroalgas marinhas
Carvalho, Luciana Retz de;Roque, Nidia F.;
Química Nova , 2000, DOI: 10.1590/S0100-40422000000600009
Abstract: during the biological evolution, marine macroalgae have developed biochemicals tools in order to utilize components of seawater such as sulfates and halogens, to produce a variety of chemicals (secondary metabolites).this review shows and discuss the occurrence of sulfated and/or halogenated phenolic compounds in seaweeds.
Fenóis halogenados e/ou sulfatados de macroalgas marinhas
Carvalho Luciana Retz de,Roque Nidia F.
Química Nova , 2000,
Abstract: During the biological evolution, marine macroalgae have developed biochemicals tools in order to utilize components of seawater such as sulfates and halogens, to produce a variety of chemicals (secondary metabolites).This review shows and discuss the occurrence of sulfated and/or halogenated phenolic compounds in seaweeds.
Effects of Ascorbic Acid in Controlling Lethal Browning in in Vitro Culture of Brahylaena huillensis Using Nodal Segments  [PDF]
Cosmas Funguomali Ndakidemi, Emerald Mneney, Patrick Alois Ndakidemi
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.51024
Abstract:

Brachylaena huillensis (Asteraceae) is a threatened resourceful timber tree species. B. huillensis regenerates only through seeds. However, the seeds have poor germination rate and are also not obtainable. Developing tissue culture techniques for B. huillensis will permit the application of biotechnology to its propagation and provide alternative method for its regeneration. The current study was conducted to investigate the effect of antioxidant ascorbic acid in controlling lethal browning caused by oxidized phenols in in vitro culture of Brachylaena huillensis using nodal segments. The treatments included four levels of ascorbic acid (0, 50, 100, 150, 200, & 250 mg/litre) supplied into basal woody plant medium supplemented with Benzylaminopurine (BAP). The results of the current study revealed that production of phenolic compounds of explants was significantly controlled by incorporating higher levels of ascorbic acid into the medium. The best control was achieved by supplying 200-250 mg/litre of ascorbic acid in the woody plant medium supplemented with BAP.

Extraction of Antioxidant Total Phenol from Lees of Xiaoqu Spirits  [PDF]
Xinzhi Cao, Fang Liu, Jia Liu, Xiao Tan, Linsheng Ren
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.611106
Abstract: By the Soxhlet extraction, ethanol is used as extraction solvent of lees to determinate the total phenol content of Xiaoqu spirits lees. Folin-phenol method is handled to extract and to determine the reducing ability of extraction. The total phenolic content in the most suitable condition is determinated by the Folin-phenol method and the optimum extraction technological condition of total phenol is determinated by the experiment. The experimental results show that the optimization conditions of the determination methods of total phenolic content are determined by 3.5 mL for the Folin phenol reagent, 1:1 for the 10% Na2CO3 ratio and 30 min for the chromogenic reaction at room temperature. The optimum extraction technological condition of total phenol from lees is as following: solid-liquid ratio 1:12, ethanol concentration 100%, extraction temperature 80℃, extraction time 10 h.
Fenóis, peroxidase e polifenoloxidase na resistência do cafeeiro a Meloidogyne incognita
Mazzafera, Paulo;Gon?alves, Wallace;Fernandes, José Afonso Righetti;
Bragantia , 1989, DOI: 10.1590/S0006-87051989000200001
Abstract: seedlings of two coffee cultivars were inoculated with the nematode meloidogyne incognita: cv. mundo novo (susceptible) of coffea arabica and cv. apoat? (resistant) of c. canephora. during the larval penetration and adult female phases of the parasite, evaluations were made on phenol content, peroxidase and polyphenoloxidase activities. in the two evaluations, no differences were observed in roots and shoots growth among inoculated and non inoculated seedling. for both cultivars, only in the first phase infected seedlings showed an increase in phenols as compared to their counterparts not inoculated. however, phenol values were higher in the second than in the first phase. the cv. mundo novo had always higher phenols content than apoat?. only inoculated seedlings of the cv. mundo novo showed an increase of peroxidase activities in the first phase; but, both cultivars presented higher peroxidase activities in the second phase as compared to the first. apoat? seedlings had always higher peroxidase and polyphenoloxidase activities than mundo novo. infected seedlings of the cv. apoat? showed in the first phase, only, an increase in polyphenoloxidase activity. thin-layer chromatograms of phenolic extracts did not present any difference among inoculated and non-inoculated seedlings. twenty three spots on the chromatograms were common to both cultivars, except that apoat? had a further nine spots not found in mundo novo and the later had a further eleven not found in the former.
The surface-active bio oil solution in sulfured copper mineral benefit
Brossard, L.E.;Varela, N.;Brossard Jr., L.E.;Brossard, C.O;Cortez, L.A B.;Magalh?es, P.G.;
Brazilian Journal of Chemical Engineering , 2005, DOI: 10.1590/S0104-66322005000100001
Abstract: surface-active bio-oil (sabo) solutions, prepared from vacuum pyrolysis bio-oil with a phenol-to-levoglucosan mass ratio of 4.8, was compared to pine-oil (po) as foaming agent in the process of flotation of sulfured copper minerals. with the aid of 23 factorial designs, regression models were obtained for % cu in flotation concentrate (lcu) and % cu recovery (r), as functions of foaming agent-to-cu mineral, collector-to-cu mineral mass ratio and liquid-to-solid ratio (v/w). experimental designs composed of a saturated design in its first half and a fold over design in its second half allowed to study the influence of flotation conditions on lcu and r when sabo was the foaming agent. the factors selected were: particle size; pulp ph; flotation time; initial cu content in the mineral (mineral type); liquid-to-solid ratio and finally sabo-to-mineral and collector-to-mineral mass ratio. within the chosen experimental region only pulp ph affected significantly both responses. it is shown that high pulp ph, in the presence of minerals rich in cu content leads to a significant increase in lcu and r. although sabo to mineral mass ratio is high compared to po, it is considered that an optimization study on pulp ph should reduce this difference making sabo an attractive alternative to po and a way to widen the field of applications of pyrolysis products.
Alternativas verdes para o preparo de amostra e determina??o de poluentes fenólicos em água
Rodrigues, Guilherme Dias;Silva, Luis Henrique Mendes da;Silva, Maria do Carmo Hespanhol da;
Química Nova , 2010, DOI: 10.1590/S0100-40422010000600027
Abstract: the restricted availability of water sources suitable for consumption and high costs for obtaining potable water has caused an increase of the conscience concerning the use. thus, there is a high demand for "environmentally safe methods" which are according to the principles of green chemistry. moreover, these methods should be able to provide reliable results for the analysis of water quality for various pollutants, such as phenol. in this work, greener alternatives for sample preparation for phenol determination in aqueous matrices are presented, which include: liquid phase microextraction, solid phase microextraction, flow analysis, cloud point extraction and aqueous two-phase systems.
Biochemical Impact of Fodder Galega (Galega orientalis Lam.) on Agro-ecosystems
Ligita Bale?entien?,Albinas Kusta
Environmental Research, Engineering and Management , 2011, DOI: 10.5755/j01.erem.58.4.678
Abstract: Multifunctional allelochemicals activities stimulate an increase in an employment spectrum of biologically active compounds in biological farming. The understanding of the allelochemical action mechanisms makes it possible to use these compounds to enhance crop production and develop a more sustainable agriculture, including weed and pest control through crop rotations, residue management and a variety of approaches in bio-control. The aim of this research was to establish and to compare the total amount of phenolic compounds and allelopathic activity of the aqueous extracts produced of different shoot parts (leaves, stems, blossoms and seed) and roots of new crop, namely fodder galega at their different growth stages. Biochemical impact of the aqueous extracts produced of fodder galega ground part and roots on the germination data of the test–object subjected significantly on the galega growth stage and extract concentration. The biochemical effect of all tested extracts and concentrations had the same tendency to inhibit the test–object seed germination. The extracts of the ground part were more toxic than those of roots and had a stronger suppressive effect on the test–plant germination. Phenols concentration and conventional coumarine unit (CCU) content increased evenly in dependence on total phenols concentration at all plant development stages accordingly to the extracts concentration gradient. Phenols concentration as well as their activity of ground part and roots increased from shooting to flowering stage.
Synthesis of new α,β-unsaturated butenolides
Veena Joshi,R.P. Chamoli
Bulletin of the Chemical Society of Ethiopia , 2010,
Abstract: A number of new &gama;-substituted α,β-unsaturated butenolides have been synthesized by the condensation of phenols with β-(3-nitrobenzoyl)acrylic acid and β-(4-methyl-3-nitrobenzoyl)acrylic acid.
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