Rapid analysis of Radix puerariae by near-infrared spectroscopy

A new, rapid analytical method using near-infrared spectroscopy (NIRS) was developed to differentiate two species of Radix puerariae (GG), Pueraria lobata (YG) and Pueraria thomsonii (FG), and to determine the contents of puerarin, daidzin and total isoflavonoid in the samples. Five isoflavonoids, puerarin, daidzin, daidzein, genistin and genistein were analyzed simultaneously by high-performance liquid chromatography-diode array detection (HPLC-DAD). The total isoflavonoid content was exploited as critical parameter for successful discrimination of the two species. Scattering effect and baseline shift in the NIR spectra were corrected and the spectral features were enhanced by several pre-processing methods. By using linear discriminant analysis (LDA) and soft independent modeling class analogy (SIMCA), samples were separated successfully into two different clusters corresponding to the two GG species. Furthermore, sensitivity and specificity of the classification models were determined to evaluate the performance. Finally, partial least squares (PLS) regression was used to build the correlation models. The results showed that the correlation coefficients of the prediction models are R = 0.970 for the puerarin, R = 0.939 for daidzin and R = 0.969 for total isoflavonoid. The outcome showed that NIRS can serve as routine screening in the quality control of Chinese herbal medicine (CHM).     

Classification and quantification analysis of Radix scutellariae from different origins with near infrared diffuse reflection spectroscopy

A rapid near infrared spectroscopy analysis method was developed for the geographical origin discrimination and content determination of Radix scutellariae, a kind of Traditional Chinese Medicine (TCM). 81 R. scutellariae samples from six different origins were analyzed with HPLC-UV as reference method. The NIR spectra were collected in integrating-sphere diffused reflection mode and processed with different spectra pretreated methods. Discriminant analysis (DA) and discriminant partial least squares (DPLS) were applied to classify the geographical origins of those samples, and the latter had a better predictive ability with 100% accuracy after two exceptional samples eliminated from the calibration set. For the quantitative calibration, the samples were divided into calibration set and validation set by Kennard-Stone algorithm. The models of baicalin, wogonoside, baicalein, wogonin were established with partial least squares (PLS) algorithm and the optimal principal component (PC) numbers were selected with Leave-One-Out (LOO) cross-validation. The established models were evaluated with the root mean square error of prediction (RMSEP) and corresponding correlation coefficients. The correlation coefficients of all the four calibration models are above 0.920, and the RMSEPs of baicalin, wogonoside, baicalein and wogonin are 0.752%, 0.094%, 0.418% and 0.139%, respectively. This research indicated that the NIR diffuse reflection spectroscopy could be used for the rapid analysis of R. scutellariae, which is beneficial to the quality control of this raw material in TCM pharmaceutical factory, and will also help to solve analogous problems.     

Novel microporous zirconium silicate (K2ZrSi3O9·2H2O) from high temperature phase transformation

A new microporous zirconosilicate K₂ZrSi₃O₉·2H₂O (AV-15) has been prepared by high-temperature phase transformation at 910 °C. Its structure has been determined ab initio from powder X-ray diffraction data. The unit cell is orthorhombic, space group C222₁ (no. 20), Z=4 with cell dimensions: a=8.105(3), b=10.684(5), c=12.030(5) Å, V=1041.76(7) Å³. The framework connection of AV-15 is essentially the same as the previously reported sodium stannosilicate AV-10 while the locations of potassium and water molecules in the former are quite different from those of the sodium and water molecules in AV-10. In AV-10 sodium and water molecules form a sinucoidal chain, while potassium and water molecules build up a linear chain in AV-15. The water molecules in AV-15 are lost on heating with a typical zeolitic behaviour. SEM shows that the particle sizes and habits of AV-15 and parent umbite material are the same. The ²⁹Si MAS NMR spectrum of AV-15 displays two resonances at ca. −89.4 and −90.1 ppm in a 1:2 intensity ratio. Thermogravimetry analysis confirms the existence of water in this material.     

Effects of process severity on the chemical structure of Miscanthus ethanol organosolv lignin

Ethanol organosolv lignin extracted from Miscanthus × giganteus with differing levels of severity (1.75 < CS<2.8) were subjected to comprehensive structural characterization by ¹³C, ³¹P NMR, FTIR spectroscopy and gel permeation chromatography. The results were compared to those from milled wood lignin from the same feedstock. The results showed that an increase in the severity of the treatment enhanced the dehydration reactions on the side chain and the condensation of lignin, increased the concentration of phenol groups and decreased the molecular mass of lignin fragments. It appeared that for the experimental conditions generally employed the cleavage of α-aryl ether bonds is primarily reaction responsible for lignin depolymerization under the organosolv conditions examined.     

Ab initio study on structure and phase transition of A- and B-type rare-earth sesquioxides Ln2O3 (Ln=La-Lu, Y, and Sc) based on density function theory

Ab initio energetic calculations based on the density functional theory (DFT) and projector augmented wave (PAW) pseudo-potentials method were performanced to determine the crystal structural parameters and phase transition data of the polymorphic rare-earth sesquioxides Ln₂O₃ (where Ln=La-Lu, Y, and Sc) with A-type (hexagonal) and B-type (monoclinic) configurations at ground state. The calculated results agree well with the limited experimental data and the critically assessed results. A set of systematic and self-consistent crystal structural parameters, energies and pressures of the phase transition were established for the whole series of the A- and B-type rare-earth sesquioxides Ln₂O₃. With the increase of the atomic number, the ionic radii of rare-earth elements Ln and the volumes of the sesquioxides Ln₂O₃ reflect the so-called “lanthanide contraction”. With the increase of the Ln³⁺-cation radius, the bulk modulus of Ln₂O₃ decreases and the polymorphic structures show a degenerative tendency.     

Simultaneous determination of selenium and arsenic contents in different extracts of Radix Astragali by enhancement effect of ethanol in hydride generation-inductively coupled plasma-atomic emission spectrometry

A new method was developed for simultaneous determination of trace arsenic and selenium in different extracts of Radix Astragali by enhancement effect of ethanol in hydride generation-inductively coupled plasma-atomic emission spectrometry (HG-ICP-AES) with a microwave digestion system. The effects of the concentration of the hydride generating reagent (NaBH₄), ethanol concentration, different extraction methods and pre-reducing reagents on selenium and arsenic emission intensity were discussed and optimized. The contents of selenium and arsenic in different extracts (polysaccharide, amino acid, astragaloside, and water decoction,) in Radix Astragali were analyzed. The proposed method was validated by the use of two plant reference samples {poplar leaf (GBW07604) and tea (GBW07605)}. The detection limits (3σ) were 7.0 ng L^− 1 and 2.0 ng L^− 1 for Se(IV) and As(III) and relative standard deviations (RSD) were 1.8% and 2.3%, respectively. The determination of Selenium and Arsenic contents in different extracts of Radix Astragali would provide useful information for the quality control of Radix Astragali.     

Crystal chemistry peculiarities of Cs2Te4O12

The Raman and IR-absorption spectra of the Cs₂Te₄O₁₂ lattice are first recorded and interpreted. Extraordinary features observed in the structure and Raman spectra of Cs₂Te₄O₁₂ are analyzed by using ab initio and lattice-dynamical model calculations. This compound is specified as a caesium-tellurium tellurate Cs₂Te^IV(Te^VIO₄)₃ in which Te^IV atoms transfer their 5p electrons to [Te^VIO₄]₃⁶⁻ tellurate anions, thus fulfilling (jointly with Cs atoms) the role of cations. The Te^VI-O-Te^VI bridge vibration Raman intensity is found abnormally weak, which is reproduced by model treatment including the Cs⁺ ion polarizability properties in consideration.     

Conformational study of lanthanide(III) complexes of N-(2-salicylaldiminatobenzyl)-1-aza-18-crown-6 by using X-ray and ab initio methods

A structural study of lanthanide complexes with the deprotonated form of the monobracchial lariat ether N-2-salicylaldiminatobenzyl-aza-18-crown-6 (L⁴) (Ln = La(III)–Tb(III)) is presented. Attempts to isolate complexes of the heaviest members of the lanthanide series were unsuccessful. The X-ray crystal structures of [Pr(L⁴)(H₂O)](ClO₄)₂ · H₂O · C₃H₈O and [Sm(L⁴)(H₂O)](ClO₄)₂ · C₃H₈O show the metal ion being bound to the eight donor atoms of the ligand backbone. Coordination number nine is completed by the oxygen atom of an inner-sphere water molecule. Two different conformations of the crown moiety (labelled as A and B) are observed in the solid state structure of the Pr(III) complex, while for the Sm(III) complex only conformation A is observed. The complexes were also characterized by means of theoretical calculations performed in vacuo at the HF level, by using the 3-21G^∗ basis set for the ligand atoms and a 46 + 4fⁿ effective core potential for lanthanides. The optimized geometries of the Pr(III) and Sm(III) complexes show an excellent agreement with the experimental structures obtained from X-ray diffraction studies. The calculated relative energies of the A and B conformations for the different [Ln(L⁴)(H₂O)]²⁺ complexes (Ln = La, Pr, Sm, Ho or Lu) indicate a progressive stabilization of the A conformation with respect to the B one upon decreasing the ionic radius of the Ln(III) ion. For the [Ln(L⁴)(H₂O)]²⁺ systems, most of the calculated bond distances between the metal ion and the coordinated donor atoms decrease along the lanthanide series, as usually observed for Ln(III) complexes. However, our ab initio calculations provide geometries in which the Ln–O(5) bond distance [O(5) is an oxygen atom of the crown moiety] increases across the lanthanide series from Sm(III) to Lu(III).     

Ab initio simulations of doped single-walled carbon nanotube sensors

The interactions between oxygen and nitrogen atoms with single-walled carbon nanotubes were investigated for nanotubes with two different geometrical configurations using first-principle calculations within the framework of the density functional theory. We introduced a new type of toxic gas sensor that can detect the presence of H₂, Cl₂, CO, and NO molecules. We also demonstrated that the sensitivity of this device can be controlled by the concentration of the dopants on the surface of the nanotube. In addition, the transport properties of the doped nanotube were studied for different concentrations of oxygen or nitrogen atoms that were randomly distributed on the surface of the single-walled carbon nanotube. We observed that small amounts of dopants can modify the electronic and transport properties of the nanotube and can lend metallic properties to the nanotube. Band-gap narrowing occurs when the nanotube is doped with either oxygen or nitrogen atoms.     

An easily-automated assay for the physiological state quantification of Pseudomonas sp. M18

In order to foreknow poorly performing cultures before wasting energy to scale them to large cultures, industrial microbial fermentation can greatly benefit from knowledge of the physiological state of cells. The method currently proposed is an easily automated physiological state determination method. We have designed one universal rRNA-specific probe for bacteria and developed novel signal probe hybridization (SPH) assay featuring no RNA extraction and no PCR amplification steps necessary to quantify the physiological state of microbial cells. The microbial cell was lysed with sonication and SDS. Signal probes were applied to hybridize and protect the rRNA target. S1 nuclease was then applied to remove the excessive signal probes, the single-stranded RNA and the mismatch RNA/DNA hybrids. The remaining signal probe was captured with a corresponding capture probe immobilized on a microplate and quantified with a horseradish peroxidase-conjugated color reaction. We then systemically optimized our assay. Results showed that the cell limit of detection (LOD) and the cell limit of quantification (LOQ) were 2.64 × 10⁴ cells and 9.86 × 10⁴ cells per well of microplate, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of signal probe were 49.0 fM and 344.0 fM respectively. Using this technique, we quantified the 16S rRNA levels during the fermentation process of Pseudomonas sp. M18. Our results indicate that the 16S rRNA levels can directly inform us about the physiological state of microbial cells. This technique has great potential for application to the microbial fermentation industry.     

Infectopyrone, a potential mycotoxin from Alternaria infectoria

A new metabolite, infectopyrone (1), has been isolated from the filamentous fungus Alternaria infectoria. The structure of 1 was elucidated by analysis of 2D NMR spectroscopic data. Compound 1 is an α-pyrone resembling known toxins, and is a useful phenotaxonomic marker for the A. infectoria species-group. Infectopyrone (1) was also produced by species within Stemphyllium and Ulocladium, and found in mouldy food.     

Characterization of milled wood lignin and ethanol organosolv lignin from miscanthus

Ethanol organosolv lignin extracted from Miscanthus × giganteus (using the following conditions: T = 190 °C, t = 60 min, sulfuric acid = 1.2% w/w, EtOH/H₂O = 0.65) and milled wood lignin from Miscanthus × giganteus were subjected to a comprehensive structural characterization by ¹³C, ³¹P NMR, FTIR, UV spectroscopies and size exclusion chromatography. The results showed that Miscanthus lignin is an H/G/S type (4%, 52%, 44% respectively) with ∼0.41 β-O-4 linkage per aromatic ring and contains coumarylate linkages (0.1/Ar). It was shown that during organosolv treatment, cleavage of β-O-4 linkages and of ester bond (acetyl and coumaryl residues) was the major mechanisms of lignin breakdown but the process did not significantly change the core of the lignin structure.     

Quantification of the push-pull effect in substituted alkenes

The quotient of the occupation numbers of π bonding and π* antibonding orbitals of the central CC partial double bond, , proved to be a useful parameter to quantify the push-pull effect completely for the first time in substituted alkenes by examination of a comprehensive set of compounds.     

FTIR spectroscopy and biochemical investigation of ethanol stressed yeast Pachysolen tannophilus

FTIR can assess multiple aspects of cell biochemistry and cytoplasmic components. The aim of this study was the FTIR examination of control and ethanol stressed Pachysolen tannophilus. The results of FTIR measurements were compared with those obtained by traditional biochemical methods. The data obtained with both FTIR and chemical methods, showed that ethanol stress led to changes in carbohydrate, lipids and proteins. This study demonstrates that the relative proportions of the major macromolecules contained in P. tannophilus cells and their changes in response to external stimuli can be determined rapidly, simultaneously and inexpensively using FTIR. The technique proved to be equally reliable to and less labour intensive than the more traditional chemical methods.     

Identification and quantification of 13 components in Angelica sinensis (Danggui) by gas chromatography-mass spectrometry coupled with pressurized liquid extraction

Angelica sinensis (Danggui in Chinese), a well-known traditional Chinese medicine, is also used as a health food product for women's care in Europe and America. Therefore, the demand for Danggui is enormous throughout the world. Due to the shortage of Angelica sinensis, Angelica acutiloba and Angelica gigas are commonly used as the substitutes of Danggui in the market of southeast Asia. However, the three common Angelica roots showed variation in their genetic and chemical composition. Up to date, it is thought that ferulic acid, ligustilide and other phthalides such as butylidenephthalide are the biologically active components of Danggui. In this paper, the contents of 13 compounds including ferulic acid, Z-ligustilide, E-ligustilide, Z-butylidenephthalide, E-butylidenephthalide, 3-butylphthalide, 3-butylidene-4-hydroxyphthalide, senkyunolide A, 6,7-epoxyligustilide, senkyunolide F, senkyunolide H, senkyunolide I, and 6,7-dihydroxyligustilide were determined or estimated by using gas chromatography-mass spectrometry (GC-MS) coupled with pressurized liquid extraction (PLE). The results showed that GC-MS coupled with PLE offered a simple, rapid and high sensitive method to analysis of components in Angelica root. And the contents of investigated compounds in Angelica sinensis, Angelica acutiloba and Angelica gigas, which are used as Danggui in China, Japan and Korea, respectively, were highly variant. It is thought that interaction of multiple chemical compounds contributes to the therapeutic effects of Chinese medicines. However, the overall clinical efficacy of these different Danggui has not been determined. Therefore, comparison of chemical components and pharmacological activities of different Angelica root is helpful to elucidate the mechanism of therapeutic effects of Danggui.     

Hupermine A,a novel C16N2-type Lycopodium alkaloid from Huperzia phlegmaria

A novel C₁₆N₂-type Lycopodium alkaloid consisting of a quinolizidine with a 6-dimethylaminohexyl side chain, hupermine A (1), was isolated from the club moss of Huperzia phlegmaria, and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Pressurized fluid extraction of carotenoids from Haematococcus pluvialis and Dunaliella salina and kavalactones from Piper methysticum

Pressurized fluid extraction (PFE) was examined as an alternative technology for the extraction of carotenoids in the green algae Haematococcus pluvialis and Dunaliella salina and kavalactones in Piper methysticum. The extraction process was optimized by varying the key extraction factors of solvent, sample-solvent ratio, temperature, and time. The selectivity and efficiency of extraction parameters were determined with high performance liquid chromatography (LC) and LC-mass spectrometry (LC-MS). Results showed that PFE utilization of conventional solvents under controlled temperature and pressure in an oxygen and light-free environment could result in the use of less solvent in a shorter period of time. PFE showed higher or equal extraction efficiencies as compared with traditional solvent extractions while maintaining the integrity of chemical components. PFE showed high potential for extraction of natural products and nutraceuticals, particularly labile and light sensitive chemicals.     

Prediction of the transport properties of a polyatomic gas

An ab initio molecular potential model is employed in this paper to show its excellent predictability for the transport properties of a polyatomic gas from molecular dynamics simulations. A quantum mechanical treatment of molecular vibrational energies is included in the Green and Kubo integral formulas for the calculation of the thermal conductivity by the Metropolis Monte Carlo method. Using CO₂ gas as an example, the fluid transport properties in the temperature range of 300–1000 K are calculated without using any experimental data. The accuracy of the calculated transport properties is significantly improved by the present model, especially for the thermal conductivity. The average deviations of the calculated results from the experimental data for self-diffusion coefficient, shear viscosity, thermal conductivity are, respectively, 2.32%, 0.71% and 2.30%.     

Overlapping chemical and genetic diversity in Ligularia lamarum and Ligularia subspicata. Isolation of ten new eremophilanes and a new seco-bakkane compound

Root chemicals and DNA sequences were analyzed for Ligularialamarum samples collected in Yunnan and Sichuan Provinces of China and the relationship between the plant and Ligulariasubspicata, its taxonomically closest species, was examined. Both species produce furanoeremophilanes and eremophilan-8-one derivatives as the major components. Eleven new compounds, including a new seco-bakkane compound, were isolated. The two species were found to harbor overlapping intra-specific diversities with respect to the chemicals and the DNA sequences.