A new lignan rhamnoside identified as 2,6-di（4＇,5＇-dihydroxyphenyl）-3,7-dioxabicyclo[3.3.0]octane-1-hydroxy-5-O-rhamnopyranoside （1） has been isolated from the ethanolic extract of seed pods of Bauhinia retusa. ...A new lignan rhamnoside identified as 2,6-di（4＇,5＇-dihydroxyphenyl）-3,7-dioxabicyclo[3.3.0]octane-1-hydroxy-5-O-rhamnopyranoside （1） has been isolated from the ethanolic extract of seed pods of Bauhinia retusa. Its structure was established by extensive spectroscopic techniques （UV, IR, 1D NMR, 2D NMR, HRESIMS）.展开更多
Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pel...Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pellegr.,Distemonanthus benthamianus and Erythrophleum ivorense A.Chev.The color of four wood species was evaluated to be consistent by the CIELab and CIE1931 color system.The boards of B.bracteosa,M.heitzii and E.ivorense was divided into dark color.The wood color of B.bracteosa had the highest red to green hue,while the wood appearance of D.benthamianus had the brightest and yellowest color within the four wood species.The whiteness of D.benthamianus was significantly higher than the other three wood species,namely tangential section 21.9%and radial section 22.2%.Hence,the color of the four species varied significantly,which was closely related to internal constituents of wood materials.M.heitzii wood had the highest surface glossiness on both tangential and radial section surfaces.The surface glossiness was highly related to the wood microstructure,especially with the pore and groove structure.This study of the visible characteristics provided the indicated knowledge for the application of the four wood species in wood industry.展开更多
In the present study,the tannins from stem and root barks of Tessmannia burttii Harms(Caesalpiniaceae),a plant species abundantly growing in Tanzania and other parts of Africa,were investigated for their suitability i...In the present study,the tannins from stem and root barks of Tessmannia burttii Harms(Caesalpiniaceae),a plant species abundantly growing in Tanzania and other parts of Africa,were investigated for their suitability in hides tanning.Tannin powder was extracted at selected temperatures(30,50 and 80°C)and the influence of each temperature on the crosslinking capacity was evaluated.The interaction mechanism between hide powder collagen and the tannins was studied by Differential Scanning Calorimetry(DSC),trinitrobenzensulfonic(TNBS)acid assay and amino acid hydrolysis methods.Extraction temperatures showed low influence on crosslinking capacity of the tannins.However,extract obtained at 50°C exhibited best performance in terms of gap size between T onset and T peak.The stem bark extract yield was higher than that from the root bark,but both were within the recommended ranges.The tannin content(61%)of T.burttii stem bark extract was above recommended value(10%),whereas its total phenolic content and total flavonoic content were found to be above that of commercial Acacia mearnsii tannin.The study of cross-linking parameters as a function of pH showed cross-linking to occur via a covalent mechanism at the basic amino groups.However,the bonds were not resistant to acid hydrolysis.The observed interaction mechanism indicated that tannins from stem and root barks of T.burttii belong to the condensed tannin,similar to A.mearnsii(black wattle),a commercial tannin source that was used in this study as a reference.Findings from this study depict that T.burttii extracts are auspicious eco-friendly alternative source of vegetable tannins to overcome the use of chromium salts in the leather industry.展开更多
文摘A new lignan rhamnoside identified as 2,6-di（4＇,5＇-dihydroxyphenyl）-3,7-dioxabicyclo[3.3.0]octane-1-hydroxy-5-O-rhamnopyranoside （1） has been isolated from the ethanolic extract of seed pods of Bauhinia retusa. Its structure was established by extensive spectroscopic techniques （UV, IR, 1D NMR, 2D NMR, HRESIMS）.
基金This work was financially supported by the Hunan Provincial Natural Science Foundation of China(2020JJ2058)Scientific Research Foundation of Hunan Provincial Education Department(18A159)Technology Innovation Project of Yihua Lifestyle Technology Co.,Ltd.(YH-JSJSKF-201708006).
文摘Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pellegr.,Distemonanthus benthamianus and Erythrophleum ivorense A.Chev.The color of four wood species was evaluated to be consistent by the CIELab and CIE1931 color system.The boards of B.bracteosa,M.heitzii and E.ivorense was divided into dark color.The wood color of B.bracteosa had the highest red to green hue,while the wood appearance of D.benthamianus had the brightest and yellowest color within the four wood species.The whiteness of D.benthamianus was significantly higher than the other three wood species,namely tangential section 21.9%and radial section 22.2%.Hence,the color of the four species varied significantly,which was closely related to internal constituents of wood materials.M.heitzii wood had the highest surface glossiness on both tangential and radial section surfaces.The surface glossiness was highly related to the wood microstructure,especially with the pore and groove structure.This study of the visible characteristics provided the indicated knowledge for the application of the four wood species in wood industry.
基金J.J.E.M.is grateful to the International Foundation for Sciences(IFS)[grant numbers Grant No.J/5528-1]for financial support involved in the plant collection.
文摘In the present study,the tannins from stem and root barks of Tessmannia burttii Harms(Caesalpiniaceae),a plant species abundantly growing in Tanzania and other parts of Africa,were investigated for their suitability in hides tanning.Tannin powder was extracted at selected temperatures(30,50 and 80°C)and the influence of each temperature on the crosslinking capacity was evaluated.The interaction mechanism between hide powder collagen and the tannins was studied by Differential Scanning Calorimetry(DSC),trinitrobenzensulfonic(TNBS)acid assay and amino acid hydrolysis methods.Extraction temperatures showed low influence on crosslinking capacity of the tannins.However,extract obtained at 50°C exhibited best performance in terms of gap size between T onset and T peak.The stem bark extract yield was higher than that from the root bark,but both were within the recommended ranges.The tannin content(61%)of T.burttii stem bark extract was above recommended value(10%),whereas its total phenolic content and total flavonoic content were found to be above that of commercial Acacia mearnsii tannin.The study of cross-linking parameters as a function of pH showed cross-linking to occur via a covalent mechanism at the basic amino groups.However,the bonds were not resistant to acid hydrolysis.The observed interaction mechanism indicated that tannins from stem and root barks of T.burttii belong to the condensed tannin,similar to A.mearnsii(black wattle),a commercial tannin source that was used in this study as a reference.Findings from this study depict that T.burttii extracts are auspicious eco-friendly alternative source of vegetable tannins to overcome the use of chromium salts in the leather industry.
