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

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

Chemical and antioxidative assessment of dietary turnip (Brassica rapa var. rapa L.)

The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,20-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity

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

Development and evaluation of an HPLC/DAD method for the analysis of phenolic compounds from olive fruits

A new HPLC/DAD methodology for separating nine phenolic compounds is described. This methodology is applied to the definition of qualitative and quantitative profiles of three Portuguese olive fruit cultivars (Cobrançosa, Madural and Verdeal). Two different extraction methods were needed for the complete definition of their profiles, one of them including a Sep-pack C18 cleaning step. The chromatographic separation was achieved using a Spherisorb ODS2 (25.0 × 0.46 cm; 5 μm, particle size) column. The solvent system used was a gradient of water-formic acid (19:1) and methanol, with a flow rate of 0.9 mL/min. The detection limit values for phenolic compounds were between 0.04 and 4.32 μg/mL and the method was precise. As a general rule, the recovery values were high. This technique can also be useful in the discrimination of Portuguese olive fruit cultivar

Energy and Momentum densities of cosmological models, with equation of state ρ=μ\rho=\mu, in general relativity and teleparallel gravity

We calculated the energy and momentum densities of stiff fluid solutions, using Einstein, Bergmann-Thomson and Landau-Lifshitz energy-momentum complexes, in both general relativity and teleparallel gravity. In our analysis we get different results comparing the aforementioned complexes with each other when calculated in the same gravitational theory, either this is in general relativity and teleparallel gravity. However, interestingly enough, each complex's value is the same either in general relativity or teleparallel gravity. Our results sustain that (i) general relativity or teleparallel gravity are equivalent theories (ii) different energy-momentum complexes do not provide the same energy and momentum densities neither in general relativity nor in teleparallel gravity. In the context of the theory of teleparallel gravity, the vector and axial-vector parts of the torsion are obtained. We show that the axial-vector torsion vanishes for the space-time under study.Comment: 15 pages, no figures, Minor typos corrected; version to appear in International Journal of Theoretical Physic

Organic acids composition of Cydonia oblonga Miller leaf

Organic acid profiles of 36 Cydonia oblonga Miller leaf samples, from three different geographical origins of northern (Bragança and Carrazeda de Ansiães) and central Portugal (Covilhã), harvested in three collection months (June, August and October of 2006), were determined by HPLC/UV (214 nm). Quince leaves presented a common organic acid profile, composed of six constituents: oxalic, citric, malic, quinic, shikimic and fumaric acids. C. oblonga leaves total organic acid content varied from 1.6 to 25.8 g/kg dry matter (mean value of 10.5 g/kg dry matter). Quinic acid was the major compound (72.2%), followed by citric acid (13.6%). Significant differences were found in malic and quinic acids relative abundances and total organic acid contents according to collection time, which indicates a possible use of these compounds as maturity markers. Between June and August seems to be the best period to harvest quince leaves for preparation of decoctions or infusions, since organic acids total content is higher in this season

Metabolic profiling and biological capacity of Pieris brassicae fed with kale (Brassica oleracea L. Var. Acephala).

Vegetables of the Brassica group are the most commonly grown and consumed worldwide. Food plants with apparent cancer and cardiovascular di sease-preventing properties include several varieties of Brassica oleraceae. The majority of the herbivorous insect species are specialized feeders, for which the behavioral decision to accept a plant as food or oviposition substrate is mainly related with sensory information. Pieris insects (Lepidoptera: Pieridae) are specialist herbivores of cruciferous plants