Phenolics: from chemistry to biology

In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, will be discussed. In addition, the increasing interest in phenolics’ biological activities is covered, and several works addressing this matter are referred

Numerical solution of linear models in economics: The SP-DG model revisited

In general, complex and large dimensional models are needed to solve real economic problems. Due to these characteristics, there is either no analytical solution for them or they are not attainable. As a result, solutions can be only obtained through numerical methods. Thus, the growing importance of computers in Economics is not surprising. This paper focuses on an implementation of the SP-DG model, using Matlab,developed by the students as part of the Computational Economics course. We also discuss some of our teaching/learning experience within the course, given for the first time in the FEP Doctoral Programme in Economics.SP-DG Model, Output, Inflation, Numerical Simulation, Teaching of Economics

Resposta da couve Tronchuda (Brassica oleracea var. costata) à aplicação de azoto e boro e de um fertilizante orgânico autorizado em agricultura biológica

Os portugueses são dos maiores apreciadores mundiais de brássicas. A couve Tronchuda é cultivada em Portugal em área superior a 1000 ha. O seu consumo é sobretudo apreciado na quadra natalícia. Neste trabalho reportam-se resultados da fertilização com azoto e boro, na forma de adubos convencionais, e da utilização de Dix10 (com 10 % N total), um fertilizante orgânico autorizado em agricultura biológica. Plantas de raiz protegida foram transplantadas a 29 de Agosto de 2005 num compasso 0,8x0,5 m. O solo, de textura franca, continha 0,83 % matéria orgânica, 5,2 pH(H2O) e teores em P e K médios e altos, respectivamente. Foram estabelecidas seis modalidades: sem adubação (SAd); Dix10, em dose equivalente a 80 kg N/ha; modalidades com 80 (NB) e 160 (N+) kg N/ha, na forma de ureia; e modalidades sem B (B-) e com aplicação de 2,2 (NB) e 4,4 (B+) kg B/ha. Todas as modalidades de B foram fertilizadas com 80 kg N/ha e as de N com 2,2 kg B/ha, coincidindo na modalidade NB as doses médias de N e B. As plantas SAd produziram 13,7 Mg biomassa/ha e exportaram 33,9 kg N/ha e 40,9 g B/ha, valores significativamente inferiores às modalidades fertilizadas. Dix10 produziu 18,0 Mg de biomassa/ha e exportou 45,1 kg N/ha e 51,3 g B/ha. A modalidade NB originou maior produção de biomassa (38,6 Mg/ha) e N exportado (107,9 kg/ha) que as modalidades SAd e Dix10. A modalidade N+ não registou aumento de produção nem de N exportado comparativamente com NB. B+ não influenciou a produção de biomassa mas aumentou a concentração de B nos tecidos e o B exportado. N+ reduziu significativamente a concentração de B nos tecidos e o B exportado, sugerindo um efeito de antagonismo da aplicação de N sobre a absorção de B. As produções obtidas e a recuperação aparente de nutrientes mostraram que a redução de produção de biomassa nas modalidades SAd e Dix10 se deveu à reduzida disponibilidade de N no solo durante a estação de crescimento. The Portuguese are one of the greatest brassica consumers in the entire world. Tall cabbage is grown in Portugal over an area greater than 1000 ha. Tall cabbage consumption is very popular at Christmas time. In this work, results from nitrogen and boron application, as conventional fertilisers, and from the use of Dix10, an organic amendment (˜ 10 % total N) permitted in organic farming, are reported. Young cabbage plants were prepared in a greenhouse in micro-pots and transplanted with protected roots on August 29, 2005, spaced at 0.8x0.5 m between and within rows. The soil was loamy textured with 0.83 % organic matter, pH(H2O) 5.2, and with median P and high K content levels. Six treatments were established: SAd treatment, without any fertilization; Dix10, applied in a rate equivalent to 80 kg N/ha; NB and N+, with 80 and 160 kg N/ha as urea, respectively; and B-and B+ treatments, without B and with 4.4 kg B/ha as borax. Boron treatments were fertilised with 80 kg N/ha and N treatments with 2.2 kg B/ha. Thus, NB is a median treatment with 80 kg N/ha and 2.2 kg B/ha. SAd plants yielded 13.7 Mg biomass/ha and took up 33.9 kg N/ha and 40.9 g B/ha, which are values significantly lower than that obtained on fertilised plots. In Dix10 treatment, cabbage yielded 18 Mg biomass/ha and took up 45.1 and 51.3 g B/ha. NB treatment produced higher biomass (38.6 Mg/ha) and N uptake (107.9 kg/ha) than SAd and Dix10 treatments. N+ treatment did not increase the yield, neither N uptake if compared with NB. B+ treatment has not any influence in biomass yield but increased tissue B content and B uptake. In N+ treatment there was a significant decrease in tissue B concentration and B uptake, which suggests antagonism of N over the uptake of B. The biomass yields and the apparent N and B recoveries showed that the lower biomass yielded in SAd and Dix10 treatments were due to a shortage of soil N availability in these treatments during the growing season

Phenolic compounds, organic acids profiles and antioxidative properties of beefsteak fungus (Fistulina hepatica)

The phenolic compounds and the organic acids composition of the edible beefsteak fungus Fistulina hepatica was determined by HPLC/DAD and HPLC/UV, respectively. The results showed a profile composed by five phenolic compounds (caffeic, p-coumaric and ellagic acids, hyperoside and quercetin) and six organic acids (oxalic, aconitic, citric, malic, ascorbic and fumaric acids). The quantification of the identified compounds revealed that ellagic acid (ca. 49.7%) and malic acid (ca. 57.9%) are the main compounds in this species. In a general way the phenolic profile revealed to be more constant than the organic acids one and could be more useful for the quality control of the species. Beefsteak fungus was also investigated for its capacity to act as a scavenger of DPPH- radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid). Good results were obtained against DPPH in a concentration-dependent manner. Beefsteak fungus also displayed good activity against superoxide radical, achieved by its capacity to act as both scavenger and xanthine oxidase inhibitor. A prooxidant effect was noticed for hydroxyl radical, which may be due to its capacity for iron ions reduction. Little ability for iron chelation was also observed. Beefsteak fungus showed a weak protective effect against hypochlorous acid

Evaluation of a numerical method to predict the polyphenol content in monovarietal olive oils

Three monovarietal virgin olive oils obtained from olives grown under biological agricultural system, in Portugal, with different ripening stages, were studied in what concerns the parameters usually related with oxidation status (total polyphenols, tocopherols, chlorophylls and carotenoids, peroxide values, oxidative stability, specific extinction coefficients K232 and K270 and titratable acidity). A total of 18 samples were analyzed: seven from Cv. Cobranc¸osa (maturation indices 1–7), five from Cv. Madural (maturation indices 3–7) and six from Cv. Verdeal Transmontana (maturation indices 1–6). Oxidative stability and polyphenols profile presented high correlation coef- ficients. Given this high correlation, a numerical method was developed and evaluated to predict total polyphenols contents in olive oil. The method is based on the kinetic equation of the oxidation process in the presence of antioxidants and on Rancimat profiles. Total polyphenols contents obtained with this method were similar to those obtained by the Folin-Ciocalteau method

Investigação Química da Marthasterias Glacialis da Costa Portuguesa, como Fonte de Compostos com Actividade Farmacêutica

Marine organisms are increasingly regarded as a promising source of bioactive molecules for human pharmacotherapy, being used in conditions such as cancer, inflammation, infection and pain.Marthasterias glacialis, also known as the spiny sea-star, is an echinoderm common in the Portuguese coast, however little information is available regarding its chemical constituents.In this work, the chemistry of this organism is reviewed taking into account the latest reports on several classes of natural products, namely carotenoids, sterols, fatty acids and amino acids.Os organismos marinhos tem sido considerados como uma fonte promissora de moléculas com actividade farmacoterapêutica para os humanos, sendo utilizadas em distintas patologias como neoplásicas, inflamatórias, infecciosas ou álgicas. A Marthasterias glacialis, também conhecida como estrela do mar espinhosa, é um equinodermo muito comum na costa portuguesa, existindo, contudo, pouca informação sobre a sua composição quimica.Pretende-se rever a quimica deste organismo tendo em conta os ultimos dados sobre as diferentes classes de produtos, nomeadamente carotenoides, esteróides, ácidos gordos e aminoácidos

Contents of carboxylic acids and two phenolics and antioxidant activity of dried Portuguese wild edible mushrooms

The organic acids and phenolics compositions of nine wild edible mushrooms species ( Suillus bellini, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Suillus luteus, and Suillus granulatus) were determined by HPLC-UV and HPLC-DAD, respectively. The antioxidant potential of these species was also assessed by using the DPPH¥ scavenging assay. The results showed that all of the species presented a profile composed of at least five organic acids: oxalic, citric, malic, quinic, and fumaric acids. In a general way, the pair of malic plus quinic acids were the major compounds. Only very small amounts of two phenolic compounds were found in some of the analyzed species: p-hydroxybenzoic acid (in A. rubescens, R. cyanoxantha, and T. equestre) and quercetin (in S. luteusand S. granulatus). All of the species exhibited a concentration-dependent scavenging ability against DPPH¥. T. rutilansrevealed the highest antioxidant capacity

Composição química e actividade antioxidante das folhas internas da couve tronchuda

A couve tronchuda (Brassica oleracea L. var. costata DC) é uma das couves mais consumidas pelos portugueses, especialmente durante o Inverno, apresentando as folhas (internas e externas) diferenças organolépticas marcadas. No presente trabalho procedeu-se à caracterização química das folhas internas de couve tronchuda, através da identificação e quantificação dos compostos fenólicos e dos ácidos orgânicos que as compõem e avaliou-se o seu potencial antioxidante. Foram identificados e quantificados, por HPLC-DAD-ESI-MS e HPLC/DAD, respectivamente, 17 compostos fenólicos: quercetina 3-O-soforósido-7-O-glucósido, ácido 3-p-cumaroilquínico, campferol 3-O-soforósido-7-O-glucósido, campferol 3-O-(cafeoil)-soforósido-7-O-glucósido, ácido sinapoilglucósido, campferol 3-O-(sinapoil)-soforósido-7-O-glucósido, campferol 3-O-(feruloil)-soforósido-7-O-glucósido, campferol 3-O-(p-cumaroil)-soforósido-7-O-glucósido, ácido 4-p-cumaroilquínico, ácido sinápico, campferol 3-O-soforósido, 3 isómeros de 1,2-di-sinapoilgentiobiose, 1-sinapoil-2-feruloilgentiobiose, 1,2,2-tri-sinapoilgentiobiose e 1,2’-di-sinapoil-2-feruloilgentiobiose. Foram também identificados e quantificados, por HPLC/UV, sete ácidos orgânicos (ácidos aconítico, cítrico, ascórbico, málico, quínico, chiquímico e fumárico). A actividade antioxidante do extracto aquoso foi aferida pela capacidade para interceptar o radical DPPH e espécies reactivas de oxigénio (radicais superóxido e hidroxilo e ácido hipocloroso), tendo revelado grande efeito protector

Tronchuda cabbage flavonoids uptake by Pieris brassicae

The flavonoid pattern of larvae of cabbage white butterfly (Pieris brassicae L.; Lepidoptera: Pieridae) reared on the leaves of tronchuda cabbage was analysed by HPLC-DAD-MS/MS-ESI. Twenty flavonoids were identified or characterised, namely 16 kaempferol and four quercetin derivatives. Kaempferol 3-O-sophoroside, a minor component of tronchuda cabbage, was found to be the main component in P. brassicae (15.8%). Apart from this, only two other flavonoids present in significant amounts in tronchuda cabbage (kaempferol 3-O-sophoroside-7-O-glucoside and kaempferol 3-O-sophoroside-7-O-sophoroside) were found in the larvae. The larvae have high amounts of quercetin derivatives (18.5%), which were present only in trace amounts in tronchuda cabbage extracts, suggesting that P. brassicae is able to selectively sequester these flavonoids. The occurrence of a high content of flavonoids not detectable in tronchuda cabbage extracts indicates that P. brassicae larvae are able to metabolize dietary flavonoids