Effect of Different Processing Methods on the Chemical Constituents of Scrophulariae Radix as Revealed by 2D NMR-Based Metabolomics

Scrophulariae Radix (SR) is one of the oldest and most frequently used Chinese herbs for oriental medicine in China. Before clinical use, the SR should be processed using different methods after harvest, such as steaming, “sweating”, and traditional fire-drying. In order to investigate the difference in chemical constituents using different processing methods, the two-dimensional (2D) ¹H-¹³C heteronuclear single quantum correlation (¹H-¹³C HSQC)-based metabolomics approach was applied to extensively characterize the difference in the chemical components in the extracts of SR processed using different processing methods. In total, 20 compounds were identified as potential chemical markers that changed significantly with different steaming durations. Seven compounds can be used as potential chemical markers to differentiate processing by sweating, hot-air drying, and steaming for 4 h. These findings could elucidate the change of chemical constituents of the processed SR and provide a guide for the processing. In addition, our protocol may represent a general approach to characterizing chemical compounds of traditional Chinese medicine (TCM) and therefore might be considered as a promising approach to exploring the scientific basis of traditional processing of TCM.     

Changes in Physicochemical Properties and Volatile Compounds of Roselle (Hibiscus sabdariffa L.) Calyx during Different Drying Methods

Fresh roselle are high in moisture and deteriorate easily, which makes drying important for extending shelf-life and increasing availability. This study investigated the influence of different drying methods (oven-drying, freeze-drying, vacuum-drying, and sun-drying) on the quality of roselle calyx expressed as physicochemical properties (moisture content, water activity, soluble solids, color), volatile compounds, and microstructure. Oven-drying and freeze-drying reduced moisture content most while vacuum-drying and sun-drying were not as efficient. All drying methods except sun-drying resulted in water activities low enough to ensure safety and quality. Vacuum-drying had no impact on color of the dry calyx and only small impact on color of water extract of calyx. Drying reduced terpenes, aldehydes, and esters but increased furans. This is expected to reduce fruity, floral, spicy, and green odors and increase caramel-like aroma. Sun-drying produced more ketones, alcohols, and esters. Scanning electron microscopy revealed that freeze-drying preserved the cell structure better, and freeze-dried samples resembled fresh samples most compared to other drying techniques. The study concludes that freeze-drying should be considered as a suitable drying method, especially with respect to preservation of structure.     

Mild steel corrosion inhibition by acid extract of leaves of Hibiscus sabdariffa as a green corrosion inhibitor and sorption behavior

A new corrosion inhibitor, namely acid extract of leaves of Hibiscus sabdariffa, has been synthesized, and its inhibiting action on the corrosion of mild steel in acidic bath (1.2 N HCl and 1.2 N H₂SO₄) has been investigated by corrosion-monitoring techniques. The results of the present study show that this compound has decent inhibiting property for mild steel corrosion in 1.2 N H₂SO₄ than 1.2 N HCl. Four sorption isotherms are tested for the data, namely Langmuir, Frumkin, Florry–Huggins, and Langmuir–Freundlich isotherms; of these the Langmuir isotherm fits the data well having correlation coefficient over 0.99 in both the acid environments.     

12-磷钨酸及其铯盐的酸位可接近性:固体核磁共振探针分子研究

 固体酸催化剂的酸位可接近性是影响催化剂性能的重要性质. 使用与反应分子大小接近的碱性探针分子三甲基膦和固体核磁共振技术,定量研究了磷钨酸及其铯盐的酸位可接近性. 结果表明,磷钨酸具有“假液相性”,三甲基膦可以接近磷钨酸体相中的酸位,在无水的磷钨酸中,有大约2/5的酸位可以被三甲基膦所接近. 磷钨酸的铯盐没有“假液相性”,探针分子只能接近催化剂表面的酸位,在无水的Cs1.5H1.5PW12O40中,只有大约5%的酸位能够被三甲基膦所接近.     

Effects of Different Processing Methods Based on Different Drying Conditions on the Active Ingredients of Salvia miltiorrhiza Bunge

Compared to the traditional processing method, fresh processing can significantly enhance the preservation of biologically active ingredients and reduce processing time. This study evaluated the influences of fresh and traditional processing based on different drying conditions (sun drying, oven drying and shade drying) on the active ingredients in the roots and rhizomes of S. miltiorrhiza. High-performance liquid chromatography (HPLC) was utilized to determine the contents of six active ingredients in the roots and rhizomes of S. miltiorrhiza. The data were analyzed by fingerprint similarity evaluation, hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results suggest that compared to the traditional processing method, the fresh processing method may significantly increase the preservation of biologically active ingredients. Furthermore, the findings demonstrated that among the three drying methods under fresh processing conditions, the shade-drying (21.02–26.38%) method is most beneficial for retaining the active ingredients in the roots and rhizomes of S. miltiorrhiza. Moreover, the fingerprint analysis identified 17 common peaks, and the similarity of fingerprints among samples processed by different methods ranged from 0.989 to 1.000. Collectively, these results suggest novel processing methods that may improve the yield of active ingredients for S. miltiorrhiza and may be implemented for industrial production.     

New Insight on Phenolic Composition and Evaluation of the Vitamin C and Nutritional Value of Smoothies Sold on the Spanish Market

Fruits and vegetables are a source of a wide range of nutrients, including bioactive compounds. These compounds have great biological activity and have been linked to the prevention of chronic non-communicable diseases. Currently, the food industry is developing new products to introduce these compounds, whereby smoothies are becoming more popular among consumers. The aim of this study was to evaluate the nutritional quality and the polyphenol and vitamin C content of smoothies available on the Spanish market. An evaluation of the nutritional information and ingredients was carried out. The phenolic compounds were determined by HPLC-ESI-TOF-MS; the vitamin C content was quantified using HPLC-UV/VIS; and the antioxidant activity was analyzed by DPPH and FRAP. Among all of the ingredients of the smoothies, coconut and banana have shown a negative impact on the polyphenol content of the smoothies. In contrast, ingredients such as orange, mango, and passion fruit had a positive correlation with the vitamin C content. Moreover, apple and red fruits showed the highest positive correlations with most of the phenolic acids, flavonoids, total phenolic compounds, and antioxidant activities. In addition, a clustering analysis was performed, and four groups were clearly defined according to the bioactive composition determined here. This research is a precious step for the formulation of new smoothies and to increase their polyphenol quality.     

Comparison of Different Extraction Processes on the Physicochemical Properties,Nutritional Components and Antioxidant Ability of Xanthoceras sorbifolia Bunge Kernel Oil

In this study, we investigated and compared the oil yield, physicochemical properties, fatty acid composition, nutrient content, and antioxidant ability of Xanthoceras sorbifolia Bunge (X. sorbifolia) kernel oils obtained by cold-pressing (CP), hexane extraction (HE), aqueous enzymatic extraction (AEE), and supercritical fluid extraction (SFE). The results indicated that X. sorbifolia oil contained a high percentage of monounsaturated fatty acids (49.31–50.38%), especially oleic acid (30.73–30.98%) and nervonic acid (2.73–3.09%) and that the extraction methods had little effect on the composition and content of fatty acids. X. sorbifolia oil is an excellent source of nervonic acid. Additionally, the HE method resulted in the highest oil yield (98.04%), oxidation stability index (9.20 h), tocopherol content (530.15 mg/kg) and sterol content (2104.07 mg/kg). The DPPH scavenging activity rates of the oil produced by SFE was the highest. Considering the health and nutritional value of oils, HE is a promising method for X. sorbifolia oil processing. According to multiple linear regression analysis, the antioxidant capacity of the oil was negatively correlated with sterol and stearic acid content and positively correlated with linoleic acid, arachidic acid and polyunsaturated fatty acid content. This information is important for improving the nutritional value and industrial production of X. sorbifolia.     

Synergic Effect of Active Sites in Zinc‐Modified ZSM‐5 Zeolites as Revealed by High‐Field Solid‐State NMR Spectroscopy

Understanding the nature of active sites in metal‐supported catalysts is of great importance towards establishing their structure–property relationships. The outstanding catalytic performance of metal‐supported catalysts is frequently ascribed to the synergic effect of different active sites, which is however not well spectroscopically characterized. Herein, we report the direct detection of surface Zn species and ¹H–⁶⁷Zn internuclear interaction between Zn²⁺ ions and Brønsted acid sites on Zn‐modified ZSM‐5 zeolites by high‐field solid‐state NMR spectroscopy. The observed promotion of C?H bond activation of methane is rationalized by the enhanced Brønsted acidity generated by synergic effects arising from the spatial proximity/interaction between Zn²⁺ ions and Brønsted acidic protons. The concentration of synergic active sites is determined by ¹H–⁶⁷Zn double‐resonance solid‐state NMR spectroscopy.     

Effect of β-cyclodextrin on the aggregation of the non-ionic surfactant Igepal CO-630 in water as studied by 1D and 2D NMR spectroscopy

The micellization process of the non-ionic surfactant, Igepal CO-630, and its inclusion complexes with β-cyclodextrin (β-CD) have been investigated by NMR spectroscopy. The critical micelle concentration of Igepal was determined by measuring the chemical shifts of different resonances. The structure and binding of the inclusion complexes between the Igepal and the β-CD have been studied by 1D proton NMR and ROESY experiments. The stoichiometry of the inclusion complex is mainly 1:1, with a slight contribution of 2:1. At high concentrations of surfactant, the plots of the chemical shifts in the absence and presence of β-CD coalesce, which indicates that the complexes do not take part into the micelles. The ROESY spectrum displays strong correlations between the internal cavity protons of the CD and the aromatic and aliphatic regions of the Igepal, suggesting the formation of a 2:1 primary face-to-face inclusion complex at high concentrations of β-CD.     

水杨酸与二烷基亚磷酸酯反应历程31P NMR与电喷雾质谱跟踪研究

The reaction between salicylic acid and dialkyl phosphite was traced by electrospray ionization mass spectrometry and ^31P NMR. All reactants, unstable intermediates and products were detected. The mechanism was proposed based on ESI-MS results and ^31P NMR profiles.     

亚硒酸钠对大鼠代谢产物影响的核磁共振研究

本文采用核磁共振(^1H NMR)技术研究了在最高耐受摄入量条件下补充亚硒酸钠对大鼠尿液代谢产物的影响。结果表明,在大鼠尿液中甲酸、乙酸、乳酸、丙氨酸、琥珀酸、甘氨酸、马尿酸、苯丙氨酸、色氨酸等代谢物谱峰信号显著增强,而柠檬酸、肌酸、尿素、尿甘素和氧化三甲胺(TAMO)的谱峰信号则显著降低。乳酸、柠檬酸和琥珀酸是体内三羧酸循环的中间产物,其代谢异常是能量代谢紊乱的标志;马尿酸、苯丙氨酸、丙氨酸的代谢异常与肾小球的滤过和回收功能有关;乙酸和甘氨酸的代谢异常则是肝功能损伤的标志,组织切片的结果也证明大鼠的肝和肾已经发生损伤,与^1H NMR的结果相一致。采用HPLC检测到补充亚硒酸钠后尿液中8-OHdG(8-hydroxy1-2′-deoxyguansoine)水平显著升高,证明体内氧化损伤的发生。以上结果表明,在最高耐受摄入量条件下补充亚硒酸钠是不安全的,用NMR方法对阐明硒的毒理学分子基础是有效的。     

运用NMR和DFT研究Michael加成反应的动力学行为及反应机理：(CO)5W=C(OEt)C2Ph作为底物

利用核磁共振方法研究了取代吡唑对炔基Fischer卡宾化合物的Michael加成的动力学行为，该反应为典型的二级反应。当吡唑的3，5-位由较大基团取代时，反应速率常数变小，而活化焓和活化熵明显增大。利用密度泛函理论研究了炔基钨卡宾为底物的Michael加成反应机理，发现吡唑上取代基团的增大可以导致第三步反应的活化能大于第一步，从而使反应的决速步骤由原来的第一步转变为第三步。     

Counterion mixing effects on the conformational transitions of polyelectrolytes. II. Counterion binding as measured by NMR spectroscopy of alkali metal poly(acrylate)s

Bound states of counterions during the coil‐globule transition of poly(acrylic acid) in water/organic solvent mixtures were investigated by NMR spectroscopy of alkali metal cations (Li⁺, Na⁺, Cs⁺). Accompanying the transition, the line widths of the respective NMR peaks significantly increased with increasing the organic solvent composition in the medium. Although this line width broadening suggests that some specific counterion binding with desolvation is involved with the coil‐globule transition, the most marked broadening was observed in higher organic solvent compositions than those of the coil‐globule transition region detected by the viscometry. Namely, the specific counterion binding with desolvation proceeds even after the polymer chain collapsed. This means in turn that such a strong counterion binding is not a prerequisite for the coil‐globule transition, at least at the stage of the onset. For the Li⁺/Cs⁺ mixed counterion system in 60 vol % DMSO, where our previous conductivity data suggested that the specific counterion binding occurred only for Cs⁺ during the coil‐globule transition induced on mixing with Li⁺, a significant increase in the line width was also observed only for Cs⁺. The coincidence between the conductivity and the NMR results for the Li⁺/Cs⁺ mixed counterion system strongly supports a working hypothesis, “size‐fitting effect,” that has been proposed to determine the counterion specificity observed for the conformational transitions of polyelectrolytes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2132–2139, 2009     

Detailed Investigation of the Immunodominant Role of O‐Antigen Stoichiometric O‐Acetylation as Revealed by Chemical Synthesis,Immunochemistry, Solution Conformation and STD‐NMR Spectroscopy for Shigella flexneri 3a

Shigella flexneri 3a causes bacillary dysentery. Its O‐antigen has the {2)‐[α‐d ‐Glcp‐(1→3)]‐α‐l ‐Rhap‐(1→2)‐α‐l ‐Rhap‐(1→3)‐[Ac→2]‐α‐l ‐Rhap‐(1→3)‐[Ac→6]_{≈40 %}‐β‐d ‐GlcpNAc‐(1→} ([(E)AB_AcC_AcD]) repeating unit, and the non‐O‐acetylated equivalent defines S. flexneri X. Propyl hepta‐, octa‐, and decasaccharides sharing the (E′)A′B_AcCD(E)A sequence, and their non‐O‐acetylated analogues were synthesized from a fully protected B_AcCD(E)A allyl glycoside. The stepwise introduction of orthogonally protected mono‐ and disaccharide imidate donors was followed by a two‐step deprotection process. Monoclonal antibody binding to twenty‐six S. flexneri types 3a and X di‐ to decasaccharides was studied by an inhibition enzyme‐linked immunosorbent assay (ELISA) and STD‐NMR spectroscopy. Epitope mapping revealed that the 2_C‐acetate dominated the recognition by monoclonal IgG and IgM antibodies and that the B_AcCD segment was essential for binding. The glucosyl side chain contributed to a lesser extent, albeit increasingly with the chain length. Moreover, tr‐NOESY analysis also showed interaction but did not reveal any meaningful conformational change upon antibody binding.     

变温核磁研究杂多酸催化芳烃磺化成砜

利用变温核磁技术研究了杂多酸同芳磺酸的作用,提出了杂多酸催化芳烃磺化成砜的作用机理。     

Molecular weight effect on the complexation of poly(methacrylic acid) and poly(ethylene oxide) as studied by high-resolution solid-state C NMR spectroscopy

Complexes of poly(methacrylic acid) (PMAA) and poly(ethylene oxide) (PEO) with different PEO molecular weight were studied by solid-state high-resolution ¹³C NMR spectroscopy, with the emphasis on the PEO molecular weight effect on inter-polymer interaction, morphology and molecular motion. It is found that the crystalline phase of PEO is completely destroyed in the complex. The results of ¹H transverse relaxation times and ¹³C spin-lattice relaxation times indicate that the chain mobility of both PEO and PMAA are greatly restricted by inter-molecular hydrogen-bonding interactions, especially when the molecular weight of PEO is 1500. The bulk structures of the complexes are found to be closely dependent on the molecular weight of PEO. The fraction of “free” PEO segments without forming hydrogen-bonds with PMAA increases with increasing PEO molecular weight.     

Eu^3^+离子与α-氨基酸配合物与介质酸度关系的 ^1^3C NMR研究

本文对Eu^3^+离子与α-氨基丙酸及组氨酸配合物体系在不同酸度条件下所表现出的^1^3CNMR波谱进行了研究,发现配合物的^1^3CNMR化学位移值随介质酸度的不同而发生规律性变化,认为这是由于不同的酸度促使配合物的结构形式产生变化所致。对长期有争议的α-氨基参与配位的酸度条件作了讨论,指出α-氨基在微酸性条件下配位的可能性,并通过计算予以进一步证实。     

制备方法对氧化镁负载的钼钒磷酸铜催化剂结构和催化性能的影响

在乙醇溶液中采用不同的浸渍方法制备了氧化镁负载的钼钒磷酸铜催化剂，利用XRD、IR和BET比表面测定等测试手段对催化剂进行了表征．XRD和IR表征结果表明，负载的钼钒磷酸铜在载体表面均匀分散，而且能够保持Keggin型结构．XRD和BET比表面测定结果说明，经12h浸渍制备的催化剂（H4PMo11VO40-CuO／MgO12H）化学和结构性能发生变化；其它两种方法制备的催化剂（H4PMo11VO40-CuO／MgO和Cu2PMo11VO40／MgO）没有化学和结构性能的变化，而且这两种催化剂具有相近的表征结果，说明两种催化剂具有相似的结构特征，以正己醇氧化脱氢生成正己醛反应评价了催化剂的催化反应性能，结果表明，H4PMo11VO40-CuO／MgO和Cu2PMO11VO40／MgO催化剂显示出比H4PM011VO40-CuO／MgO12H更高的催化反应活性。     

In Situ Crystallization of Bacterial Cellulose III. Influences of Different Polymeric Additives on the Formation of Microfibrils as Revealed by Transmission Electron Microscopy

Effects of polymer additives on the formation of microfibrils of bacterial cellulose have been examined by transmission electron microscopy. Among additives with different degrees of polymerization (DP) or substitution (DS), carboxymethyl cellulose sodium salt (CMC) with DP = 80 and DS = 0.57 is the most effective in producing separate, smaller-size microfibrils. By increasing the concentration of this CMC from 0.1 to 1.5%, the percentage of microfibrils measuring 3–7 nm wide is increased and levels off at around 1.0%. Other polymer additives such as xyloglucan are less effective than CMC in producing microfibrils with smaller sizes and the resulting microfibrils still tend to aggregate. The number of charged substituents and the molecular weight seem to be important factors in the production of highly separate smaller-size microfibrils. The reduction in average microfibril size is well correlated to the decrease in mass fraction of cellulose I in bacterial cellulose crystals. On the basis of these results, the mechanism of the crystallization of celluloses I and I is discussed. The effect of colony types, smooth and rough, on the formation of microfibrils in the presence of CMC is also described.     

The effects of anticalcification treatments and hydration on the molecular dynamics of bovine pericardium collagen as revealed by 13C solid‐state NMR

This article describes a solid‐state NMR (SSNMR) investigation of the influence of hydration and chemical cross‐linking on the molecular dynamics of the constituents of the bovine pericardium (BP) tissues and its relation to the mechanical properties of the tissue. Samples of natural phenetylamine‐diepoxide (DE)‐ and glutaraldehyde (GL)‐fixed BP were investigated by ¹³C cross‐polarization SSNMR to probe the dynamics of the collagen, and the results were correlated to the mechanical properties of the tissues, probed by dynamical mechanical analysis. For samples of natural BP, the NMR results show that the higher the hydration level the more pronounced the molecular dynamics of the collagen backbone and sidechains, decreasing the tissue's elastic modulus. In contrast, in DE‐ and GL‐treated samples, the collagen molecules are more rigid, and the hydration seems to be less effective in increasing the collagen molecular dynamics and reducing the mechanical strength of the samples. This is mostly attributed to the presence of cross‐links between the collagen plates, which renders the collagen mobility less dependent on the water absorption in chemically treated samples. Copyright © 2010 John Wiley & Sons, Ltd.