321 research outputs found

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

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    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

    Phenolic profile and antioxidative properties of the beefsteak fungus Fistulina hepatica

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    The phenolic composition of the edible beefsteak fungus Fistulina hepatica was determined by HPLC/DAD. The results showed a profile composed by caffeic, p-coumaric and ellagic acids, hyperoside and quercetin. Ellagic acid was the main compound in this 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 and superoxide radicals and hypochlorous acid but a prooxidant effect was observed for hydroxyl radical

    Quantitation of nine organic acids in wild mushrooms

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    The organic acids composition of six wild edible mushroom species ( Amanita caesarea, Boletus edulis, Gyroporus castaneus, Lactarius deliciosus, Suillus collinitus, and Xerocomus chrysenteron) was determined by an HPLC-UV detector method. The results showed that all of the samples presented a profile composed of at least five organic acids: citric, ketoglutaric, malic, succinic, and fumaric acids. Several samples also contained oxalic, ascorbic, quinic, and shikimic acids. In a general way, the quantitation of the identified compounds indicated that malic acid, followed by the pair citric plus ketoglutaric acids, were the main compounds in the analyzed species, with the exception of A. caesarea, in which malic and ascorbic acids were the most abundant compounds. The relative amounts and the presence/absence of each identified compound may be useful for the differentiation of the species

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

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    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 DPPHÂĄ 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 DPPHÂĄ. T. rutilansrevealed the highest antioxidant capacity

    Papaya Ringspot Virus Resistance of Transgenic Rainbow and SunUp is Affected by Gene Dosage, Plant Development, and Coat Protein Homology

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    R1 plants of the transgenic papaya line 55-1, which expresses a single coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) HA from Hawaii, were previously shown to be resistant only to PRSV isolates from Hawaii. Two transgenic papaya cultivars were subsequently derived from line 55-1. UH SunUp (SunUp) is homozygous for the CP gene insertion and UH Rainbow (Rainbow) is hemizygous for the CP gene because it is a F1 hybrid of a cross between SunUp and the nontransgenic papaya cultivar Kapoho. To determine the various parameters that affect the resistance of SunUp and Rainbow, plants at different developmental stages (younger and older) were inoculated with PRSV isolates from Hawaii, Brazil, Jamaica, and Thailand. Hawaiian isolates shared nucleotide sequence identities of 96.7-99.8% to the CP transgene, and the other isolates shared sequence identities of 89.5-92.5%. Resistance was affected by CP gene dosage, plant developmental stage, and CP sequence identity of the challenge isolate. Young and older hemizygous Rainbow plants were resistant to the homologous PRSV HA (99.8% homology to CP transgene), while only older Rainbow plants were resistant to the other Hawaiian isolates (96.7% homology). However, all inoculated Rainbow plants were susceptible to PRSV isolates collected from Jamaica, Brazil, and Thailand. In contrast, SunUp was resistant to all PRSV isolates, except the one from Thailand, regardless of the plant developmental stage. Resistance to the Thailand isolate, which shares 89.5% homology to the transgene, was observed only with SunUp plants inoculated at an older stage. Steady state RNA analysis and nuclear run-on experiments suggested that resistance of the transgenic papaya is RNA-mediated via post-transcriptional gene silencin

    Antioxidant potential and relation with chemical composition of wild edible mushrooms cap and stipe

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    A comparative study of the organic acids and phenolics composition and of the total alkaloids content of entire wild edible mushrooms (Russula cyanoxantha, Amanita rubescens, Suillus granulatus and [Boletus edulis) and correspondent cap and stipe was performed. All species presented oxalic, citric, malic and fumaric acids. Phenolic compounds were present in all of the analyzed species, beingp-hydroxybenzoic acid identified in A. rubescens and S. granulatus species. It seems that this compound may have a propensity to accumulate in the cap of A. rubescens. B. edulis was the species that presented the highest total alkaloids amounts. All species revealed DPPH radical scavenging activity, being B. edulis the most effective one

    Effect of the conservation procedure on the contents of phenolic compounds and organic acids in Chanterelle (Cantharellus cibarius) Mushroom

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    To check the influence of the conservation procedure in the chemical composition of chanterelle mushroom, phenolic compounds and organic acids of samples preserved under four different conditions (drying, freezing, conservation in olive oil and in vinegar) were determined. Phenolics and organic acids were analyzed by HPLC-DAD and HPLC-UV, respectively. The results showed that chanterelle is characterized by the presence of six phenolic compounds (3-, 4-, and 5-O-caffeoylquinic acid, caffeic acid, p-coumaric acid, and rutin) and five organic acids (citric, ascorbic, malic, shikimic, and fumaric acids). Samples preserved in olive oil also exhibited hydroxytyrosol, tyrosol, luteolin, and apigenin, whereas conservation in vinegar led to the detection of hydroxytyrosol, tyrosol, and tartaric acid in the analyzed samples. The conservation procedures to which chanterelle samples were subjected seem to affect the qualitative and quantitative phenolics and organic acids profiles

    Comparative study of phytochemicals and antioxidant potential of wild edible mushroom caps and stipes

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    A comparative study of the organic acids and phenolics composition and of the total alkaloids content of entire wild edible mushrooms (Russula cyanoxantha, Amanita rubescens, Suillus granulatus and Boletus edulis) and correspondent caps and stipes was performed. All species presented oxalic, citric, malic and fumaric acids, with A. rubescens exhibiting the highest total organic acids content. Organic acids were preferably fixed in the cap. Among phenolics, only p-hydroxybenzoic acid was found in A. rubescens and S. granulatus, in very low amounts. B. edulis was the species that presented the highest total alkaloid amounts. Except for this species, alkaloids mainly accumulated in the cap. All of the species exhibited a concentration-dependent scavenging ability against DPPH . B. edulis revealed the highest antioxidant capacity. The cap seemed to be the part with highest antioxidant potential. Some relationships between chemical composition and antioxidant capacity were consideredFundação para a Ciência e a Tecnologia for a grant (SFRH/BD/22108/2005

    Phenolic compounds and antimicrobial activity of olive (Olea europaea L. Cv. Cobrancosa) leaves.

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    We report the determination of phenolic compounds in olive leaves by reversedphase HPLC/DAD, and the evaluation of their in vitro activity against several microorganisms that may be causal agents of human intestinal and respiratory tract infections, namely Gram positive (Bacillus cereus, B. subtilis and Staphylococcus aureus), Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae) and fungi (Candida albicans and Cryptococcus neoformans). Seven phenolic compounds were identified and quantified: caffeic acid, verbascoside, oleuropein, luteolin 7-O-glucoside, rutin, apigenin 7-O-glucoside and luteolin 4’-O-glucoside. At low concentrations olive leafs extracts showed an unusual combined antibacterial and antifungal action, which suggest their great potential as nutraceuticals, particulalry as a source of phenolic compounds
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