Free-radical scavenging capacity and reducing power of wild edible mushrooms from northeast Portugal: Individual cap and stipe activity

The antioxidant properties of two wild edible mushroom species from the northeast of Portugal, Lactarius deliciosus (L.) Gray and Tricholoma portentosum (Fr.) Quél., were evaluated. Methanolic extracts from the entire mushroom, the cap and the stipe, separately, were screened for their reducing power and free radical scavenging capacity by chemical assays. The total phenolic content was determined, in order to assess its effect on the extract’s antioxidant activity. Both two species showed antioxidant potential; but L. deliciosus proved to be more active. The portion of the mushroom used had an influence on the results obtained, with the cap methanolic extracts exhibiting the greatest antioxidant effect.     

不同品种桑椹酒抗氧化能力及其多酚含量分析

对6个不同品种的桑椹酒的总酚、总类黄酮、原花青素、总花色苷及桑椹酒中主要的两种花色苷（矢车菊-3-氧-芸香糖苷和矢车菊-3-氧-葡萄糖苷）的总抗氧化能力及其相关性进行了分析.结果表明,不同品种的总酚、总类黄酮、原花青素、总花色苷、矢车菊-3-氧-葡萄糖苷、矢车菊-3-氧-芸香糖苷和总抗氧化能力变幅和变异系数较大,存在显著差异（P＜0.05）;桑椹酒总抗氧化能力与总酚、总类黄酮、原花青素、总花色苷及矢车菊-3-氧-葡萄糖苷和矢车菊-3-氧-芸香糖苷含量之间存在正相关性,其中与总酚的相关性最强,达到0.917 2.     

β-Cyclodextrin Based Molecularly Imprinted Solid Phase Extraction for Class Selective Extraction of Priority Phenols in Water Samples

Molecular imprinted polymer (MIP MAA-β-CD) with 2,4-dichlorophenol (2,4-DCP) and methacrylic acid functionalized β-cyclodextrin (MAA-β-CD) as the template molecule and the functional monomer, respectively, was prepared and used in molecular imprinted-solid phase extraction (MISPE) for the extraction of phenols (2,4-dichlorophenol, 2-chlorophenol, 4-chloro-3-methylphenol, 4-chlorophenol, 2,4,6-trichlorophenol, and 2-nitrophenol) from water samples. The MISPE method was optimized prior to the determination using gas chromatography coupled with a flame ionization detector (GC-FID). Under the optimized conditions, the MIP MAA-β-CD sorbent showed good linearity (0.01-12 mgL^?1), low limits of detection (0.14-0.75 µgL^?1), and good repeatability (RSD 2.3-3.6%, n = 3). Good recoveries were obtained in the range of 97-115% for tap water and between 88-103% for river water. The developed MIP MAA-β-CD SPE was then compared with other adsorbents. The unique properties of β-CD and presence of imprinted cavities explains the higher extraction recoveries obtained for phenols when using MIP MAA-β-CD SPE.     

Environmentally friendly phthalocyanine catalysts for water decontamination—Non-photocatalytic systems

Macrocyclic porphyrin-like compounds known as phthalocyanines (Pcs) have been shown to produce singlet oxygen species upon illumination with light of an appropriate wavelength. Singlet oxygen is an effective agent for complete oxidation of common water-soluble pollutants including chlorinated phenols. The most active are, in this respect, phthalocyanines bearing Al, Zn and Si central atoms. Although these compounds were proofed to be virtually non-toxic, the presence of the Al³⁺ and Zn²⁺ ions may contradict this. On the other hand e.g. iron phthalocyanine (FePc) does not represent any danger from this point of view. However, due to the specific coordination of its central metal ion and also because of the number of electrons occupying its valence orbitals, the FePc cannot be effectively activated by the photon flux. Here we report on an alternative system in the dark. It is based on the initial catalytic decomposition of various peroxo substances by metal Pc, producing oxidising species which can decompose chlorinated phenols. A series of Pcs and peroxo substances were compared and the reaction system optimised. It was shown that the highest activity was revealed for the system comprising of FePc and tert-butylhydroperoxide. Iron phthalocyanine was also successfully immobilised on an Al₂O₃ solid matrix, and this heterogeneous system was tested analogously to the homogeneous one. Virtually zero leaching of the anchored complex was detected and the activity was found to be comfortably high.     

4—氨基安替比林法测定挥发性酚空白值对校准曲线斜率的影响

4-氨基安替比林(4-AAP)试剂易吸潮结块并受空气氧化,从而使试剂空白值明显增高,必要时可将4-AAP试剂纯化。本文研究了4-AAP试剂空白值对校准曲线斜率的影响,并得出测定挥发性酚时,4-AAP试剂空白吸光度控制在0.045～0.100为最佳。     

Chemically mediated behavior in Acari: Adapations for finding hosts and mates

Ticks and mites respond to a limited spectrum of stimuli in their search for hosts and mates. Airborne chemical signals include carbon dioxide, ammonia, organic acids, terpenoids, 2,6-dichlorophenol, and other phenolic compounds. These are detected primarily by sensilla in and adjacent to Haller's organ. Most ixodid species examined have one or more multiporose sensilla that detect such volatiles. These olfactoreceptors enable the ticks to respond to remote volatile chemicals from hosts and from the other ticks, e.g., sex pheromones. Other sensilla, probably mechanogustatory in function, also occur on the tarsi. Gustatory sensilla on the palps detect assembly pheromones that enable ticks and mites to respond to conspecific or heterospecific chemical stimuli in their environment. Responses to those stimuli in ticks result in clustering, i.e., arrestant behavior. Arrestant behavior also occurs in certain mites. Finally, cheliceral chemosensilla enable ticks to recognize specific phagostimulants in host blood, e.g., ATP and glutathione, that stimulate feeding. InDennacentor variabilis andD. andersoni, these same cheliceral chemosensilla recognize species-specific genital sex pheromones in the vulvae of conspecific mates, without which they do not copulate.     

卤代酚对水生梨形四膜虫急锐毒性的QSAR研究

应用HyperChem7．O计算与卤代苯酚对水生四膜虫毒性相关的量化参数以及自己设计的结构编码参数,对31种卤代酚的毒性做QSAR研究。使用逐步回归筛选出影响卤代苯酚毒性的主要参数分子表面积S、分子体积ν和编码参数R3和R6建立QSAR方程。用留一法验证该模型,检验结果相关系数R为0．9496,标准偏差s为0．2606,与回归拟合得到的R=O．9686,s =0．2067十分接近,表明所建立的QSAR方程具有较好的预测效果和较高的预测稳定性。对QSAR方程各参数对卤代苯酚毒性的影响分析表明,S、ν影响卤代酚的基本毒性,R6影响极性麻醉,而R3则既与卤代酚基本毒性有关,也与极性麻醉有关。     

Influence of Dekkera bruxellensis on the contents of anthocyanins,organic acids and volatile phenols of Dão red wine

The anthocyanin, organic acid and volatile phenol compositions of red wine obtained from Touriga Nacional grapes growing in the Dão region (Portugal) were determined by HPLC/DAD, HPLC/UV and GC/FID, respectively. By these means, nine anthocyanic compounds (malvidin-3,5-O-diglucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, malvidin-3-O-glucoside, delphinidin, cyanidin, pelargonidin and malvidin), six organic acids (ketoglutaric, tartaric, malic, quinic, lactic and shikimic acids) and two volatile phenols (4-ethylguaiacol and 4-ethylphenol) were identified and quantified. Malvidin-3-O-glucoside, the pair lactic plus shikimic acids and 4-ethylguaiacol were the main anthocyanin, organic acids and volatile phenol, respectively. The effects of nine different Dekkera bruxellensis strains on these chemical parameters were also evaluated. The results obtained indicate that some strains of D. bruxellensis yeast are able to cause deterioration of red wine from the Dão region during its maturation by the production of volatile phenols, namely 4-ethylphenol.     

Measurement of phenols dearomatization via electrolysis: The UV-Vis solid phase extraction method

Dearomatization levels during electrochemical oxidation of p-methoxyphenol (PMP) and p-nitrophenol (PNP) have been determined through UV-Vis spectroscopy using solid phase extraction (UV-Vis/SPE). The results show that the method is satisfactory to determine the ratio between aromatic compounds and aliphatic acids and reaction kinetics parameters during treatment of wastewater, in agreement with results obtained from numerical deconvolution of UV-Vis spectra. Analysis of solutions obtained from electrolysis of substituted phenols on antimony-doped tin oxide (SnO₂Sb) showed that an electron acceptor substituting group favored the aromatic ring opening reaction, preventing formation of intermediate quinone during oxidation.