The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by che...The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).展开更多
The antioxidant capacity and changes in chemical composition of two grape varieties, the new hybrid BRS-Carmem and the Bord6 grape （Vitis labrusca） and of their products （juice, wine and vinegar） were evaluated by...The antioxidant capacity and changes in chemical composition of two grape varieties, the new hybrid BRS-Carmem and the Bord6 grape （Vitis labrusca） and of their products （juice, wine and vinegar） were evaluated by several techniques. The DPPH method was used to measure the antioxidant capacity, whereas, the total phenolic contents （TPC） were measured by Folin-Ciocalteau method. Overall chemical composition was also monitored by ESI-MS fingerprints and UPLC-MS analysis. For both grape varieties, the highest （and similar） antioxidant capacity and TPC were observed for the wine and vinegar samples followed by the grapes and then the juices. In addition, ESI-MS fingerprints and UPLC-MS analysis in the negative ion mode indicated substantial changes in chemical composition from grape to juice and wine, and then to vinegar.展开更多
文摘The American chestnut (<em>Castanea dentata</em>) was once a dominant tree species in the Appalachian Mountains and played a critical role in the ecological system. However, it was nearly eliminated by chestnut blight caused by the Ascomycetous fungus <em>Cryphonectria parasitica</em>. Identification of compounds specific to species and backcross hybrids may help further refine disease resistance breeding and testing. Phenolic compounds produced by plants are significant to their defense mechanisms against fungal pathogens. Therefore, an analytical platform has been developed to estimate the total phenolic content in leaf tissues of the American chestnut, Chinese chestnut (<em>Castanea mollissima</em>), and their backcross breeding generations (B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>) using the Folin-Ciocalteu reagent assay with UV/Vis spectrophotometry which may be used to predict blight resistance. Adsorption (765 nm) results from leaf tissue extraction in methanol/water (95%:5% v/v) and pH 2, show that the variations among these four tree species are significant (ANOVA p = 2.3 × 10<sup>-7</sup>). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, Elovich, and power law models. In addition, extensive analysis using headspace solid phase microextraction (SPME) gas chromatography and mass spectrometry was conducted to identify volatile organic compounds (VOCs) from the leaf of American chestnut, Chinese chestnut, and their backcross hybrids B<sub>3</sub>F<sub>2</sub> and B<sub>3</sub>F<sub>3</sub>. A total of 67 VOCs were identified among all chestnut types. Many of the metabolites associated with the Chinese chestnut have been reported to have antifungal properties, whereas the native and hybrid American chestnut metabolites have not. Most of the antifungal metabolites showed the strongest efficacy towards the Ascomycota phylum. A partial least squares discriminant analysis (PLS-DA) model (R<sup>2</sup>X = 0.884, R<sup>2</sup>Y = 0.917, Q<sup>2</sup> = 0.584) differentiated chestnut species and hybrids within the first five principal component (PCs).
文摘The antioxidant capacity and changes in chemical composition of two grape varieties, the new hybrid BRS-Carmem and the Bord6 grape （Vitis labrusca） and of their products （juice, wine and vinegar） were evaluated by several techniques. The DPPH method was used to measure the antioxidant capacity, whereas, the total phenolic contents （TPC） were measured by Folin-Ciocalteau method. Overall chemical composition was also monitored by ESI-MS fingerprints and UPLC-MS analysis. For both grape varieties, the highest （and similar） antioxidant capacity and TPC were observed for the wine and vinegar samples followed by the grapes and then the juices. In addition, ESI-MS fingerprints and UPLC-MS analysis in the negative ion mode indicated substantial changes in chemical composition from grape to juice and wine, and then to vinegar.
