995 resultados para Phenolic products derivatives


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Field lab in marketing: Children consumer behaviour

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This project aims to explore the Portuguese Beauty and Cosmetics market, and to discuss the usage and purchase behaviour of young female adults, between 18 and 26 years old. After a market analysis based on secondary data, it evaluates the results of qualitative and quantitative research based on 9 interviews and 126 online questionnaires to explore the consumers’ reasoning when choosing products from this category – fragrances, skin care or make-up – as well as their attitude towards brands, with a special focus on the premium cosmetics brand Lancôme. Contrary to our expectations there was no statistically significant positive influence of the online touchpoints within this age segment’s purchase intention. However, results indicate that Lancôme is already being perceived by some as young and modern, but is still suffering the threat of Mass Market brands that are valued by this target, mainly due to a price sensitivity towards premium beauty brands.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In recent years the research of sensors with good sensitivity and good selectivity in aqueous medium has been of great interest. Chemosensors soluble in aqueous media are very interesting, because of the importance in revealing a number of biological processes, disease states and environmental pollutions. 2,4,5-Triaryl-imidazoles are versatile compounds with application in medicine, due to their biological activity, and materials sciences, for their interesting optical properties. These properties can be tuned by careful selection of substituents at positions 2, 4 and 5: replacement of the aryl group by a heterocyclic group results in larger π-conjugated systems with improved optical properties for application in nonlinear optics, OLEDs, DNA intercalators, and chemosensors. In this communication, we report the synthesis of new phenanthroimidazoles, substituted at position 2 with (hetero)aryl groups of different electronic character, in order to evaluate their photophysical properties and chemosensory ability. The new derivatives were characterized by the usual techniques and a detailed photophysical study was undertaken. The evaluation of the compounds as fluorimetric chemosensors was carried out by performing titrations in acetonitrile and acetonitrile/water in the presence of relevant organic and inorganic anions, and of alkaline, alkaline-earth and transition metal cations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

With increasing business competitiveness, companies have sought to adapt their processes and / or products to worldwide established quality standards in order to achieve a greater share of consumers having as favorable aspect the quality assurance of the products and/or services provided. It was observed that companies of different sizes have different challenges regarding the certification however, the degree of difficulty is the same for all of them. The objective of this paper is to verify the reasons for the implementation of ISO 9001, the obstacles encountered during the implementation, the benefits arising from the use of the quality management system and the degree of difficulty to implement this standard. This work was developed based on a survey involving companies certified with ISO 9001:2008 from the productive sector of sugar, ethanol and derivatives of sugarcane, located in all Brazilian states. It was observed that companies of different sizes have different challenges regarding the certification however the degree of difficulty is the same for all of them. Thus, we believe that expected results represent a very important contribution to examining the reasons, benefits and difficulties of the ISO 9001 to both, the companies and certification bodies, and to researchers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

[Excerpt] Purine nucleobases are essential biomolecules in living organisms. Playing several key roles in the cell, they have been a significant inspiration for drug design.1 Benzimidazole nucleus is an important pharmacophore in the development of molecules with pharmaceutical or biological interest. Benzimidazoles have been reported to display significant pharmacological activities such as antiulcer, antifungal, antiparkinson, anticancer and antibiotic.2 Fused structures incorporating these two scaffolds might be important for medicinal chemistry and, to the best of our knowledge, there are no reports of these systems in the literature. In particular, benzo[4,5]imidazo[2,1]purines seem to be novel and must be important target molecules in the heterocyclic synthesis. (...)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

[Excerpt] The imidazole nucleus is present in a significant number of biomolecules and the inclusion of this moiety in organic scaffolds is considered an important synthetic strategy in drug discovery.[1] 5-Aminoimidazoles are interesting building blocks in medicinal chemistry since they are key components in many bioactive molecules and their derivatives showed a wide pharmacological potential as anticancer drugs.[1] The hydrazones constitute an important class of biological active drug molecules due to their wide range of pharmacological properties that include antitumoral activities.[2] Amidrazone derivatives could be considered very promising in the perspective of new drug discovery, because they are very effective as building blocks to obtain various heterocycles.[2,3] The α-hydrazononitriles are a special case of compounds belonging to the family of hydrazones that is less common in the literature, but has a great interest due to their pharmacological applications.[4] (...)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The severity and frequency of opportunistic fungal infections still growing, concomitantly to the increasing rates of antimicrobial drugs resistance. Natural matrices have been used over years due to its multitude of health benefits, including antifungal potential. Thus, the present work aims to evaluate the anti-Candida potential of the phenolic extract and individual phenolic compounds of Glycyrrhiza glabra L. (licorice), by disc diffusion assay, followed by determination of the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) for both planktonic cells and biofilms. Licorice extract evidenced inhibitory potential against the nineteen tested Candida strains, but no pronounced effect was observed by testing the most abundant individual phenolic compounds. Candida tropicalis strains were the most sensible, followed by Candida glabrata, Candida parapsilosis and, then, Candida albicans. Lower MIC and MFC values were achieved to C. glabrata and C. tropicalis, which confirms its susceptibility to licorice extract; however, for C. tropicalis strains a higher variability was observed. Anti-biofilm potential was also achieved, being most evident in some C. glabrata and C. tropicalis strains. In general, a twice concentration of the MIC was necessary for planktonic cells to obtain a similar potential to that one observed for biofilms. Thus, an upcoming approach for new antifungal agents, more effective and safer than the current ones, is stablished; notwithstanding, further studies are necessary in order to understand its mechanism of action, as also to assess kinetic parameters.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that occur naturally in agricultural commodities worldwide. Aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone, trichothecenes and ergot alkaloids are presently the most important for food and feed safety. These compounds are produced by several species that belong to the Aspergillus, Penicillium, Fusarium and Claviceps genera and can be carcinogenic, mutagenic, teratogenic, cytotoxic, neurotoxic, nephrotoxic, estrogenic and immunosuppressant. Human and animal exposure to mycotoxins is generally assessed by taking into account data on the occurrence of mycotoxins in food and feed as well as data on the consumption patterns of the concerned population. This evaluation is crucial to support measures to reduce consumer exposure to mycotoxins. This work reviews the occurrence and levels of mycotoxins in Portuguese food and feed to provide a global overview of this issue in Portugal. With the information collected, the exposure of the Portuguese population to those mycotoxins is assessed, and the estimated dietary intakes are presented.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Numerous diseases have been related with free radicals overproduction and oxidative stress. Botanical preparations possess a multitude of bioactive properties, including antioxidant potential, which has been mainly related with the presence of phenolic compounds. However, the mechanisms of action of these phytochemicals, in vivo effects, bioavailability and bio-efficacy still need research. Scope and Approach: The present report aims to provide a critical review on the aspects related with the in vivo antioxidant activity of phenolic extracts and compounds from plant origin. Key findings: Biological functions beyond the human metabolism were discussed, comparing in vivo vs. in vitro studies, as also focusing the conditioning factors for phenolic compounds bioavailability and bio-efficacy. Furthermore, an upcoming perspective about the use of phytochemicals as life expectancy promoters and anti-aging factors in human individuals was provided. Conclusions: Overall, and despite all of those advances, the study of the biological potential of numerous natural matrices still remains a hot topic among the scientific community. In fact, the available knowledge about the responsible phytochemicals for the biological potential, their mechanisms of action, the establishment of therapeutic and prophylactic doses, and even the occurrence of biochemical inter-relations, is considerable scarce.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We investigated the reductive intramolecular cyclization of bromopropargyl ethers derivatives, catalyzed by electrogenerated (1,4,8,11-tetramethyl-1,4,8,11-tetraaza-cyclotetradecane)nickel(I), [Ni(tmc)]+ as the catalysts in N,N,N-trimethyl-N-(2- hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide,[N1 1 1 2(OH)][NTf2] and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C2mim][NTf2] by cyclic voltammetry and controlled-potential electrolysis. The results show that the reaction leads to the formation of the expected cyclic compounds, which are important intermediates in the synthesis of natural products with possible biological activities.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Phenolic acids are present in our diet in different foods. In particular, mushrooms are a good source of these molecules. Due to their bioactive properties, phenolic acids are extensively studied and there is evidence of their role in disease prevention. Nevertheless, in vivo, these compounds are metabolized and circulate in the organism as glucuronated, sulfated and methylated metabolites, displaying higher or lower bioactivity. To clarify the importance of the metabolism of phenolic acids, the knowledge about the bioactivity of the metabolites is extremely important. In this review, chemical features, biosynthesis and bioavailability of phenolic acids are discussed as well as the chemical and enzymatic synthesis of their metabolites. Finally, the metabolites bioactive properties are compared with that of the corresponding parental compounds.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mushrooms are rich sources of bioactive compounds such as phenolic acids. When ingested, these molecules have to be released from the matrix to be transformed/absorbed by the organism, so that they can exert their bioactivity. Several in vitro methodologies have been developed in order to evaluate the bioavailability of bioactive compounds. Herein, two Hericium species were analyzed for their chemical composition and antioxidant activity. Furthermore, an in vitro digestion of the mushrooms and mushroom phenolic extracts was performed, and the digested samples were also submitted to antioxidant activity evaluation in order to evaluate the bioaccessibility of the phenolic acids identified in the samples. Hericium species showed similar chemical profiles (except for tocopherols), varying only in the concentration of the compounds. The phenolic extracts revealed higher antioxidant activity than the in vitro digested samples, meaning that this process decrease the antioxidant properties of the extract/mushroom. Nevertheless, phenolic acids were found in the digested samples, meaning that those molecules are bioaccessible.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de Doutoramento em Ciências (Especialidade em Química)