Authors:Y.-F. Yang, X.-Y. Lai, G.-L. Huang, Y.-H. Chen, X.-P. Du, Z.-D. Jiang, F. Chen, and H. Ni
Bee pollen is a health food with a wide range of nutritional and therapeutic properties. However, the bioactive compounds of bee pollen have not been extensively revealed due to low efficacy in separation. High-speed counter-current chromatography (HSCCC) and solvent extraction were applied to separate tyrosinase inhibitors from camellia pollen in this study. The camellia pollen extracts prepared with petroleum ether, ethyl acetate, and n-BuOH have tyrosinase inhibitory activity. Acidic hydrolysis could promote the tyrosinase inhibitory activity of crude sample. Three fractions with tyrosinase inhibitory activity were separated from the hydrolysate by a one-step HSCCC procedure. Among the fractions, two chemicals were sufficiently purified and identified to be levulinic acid (LA) and 5-hydroxymethylfurfural (5-HMF). The recovery was 0.80 g kg−1 pollen for LA and 1.75 g kg−1 pollen for 5-HMF; and their purity was all over 98%. The study demonstrates that HSCCC method is powerful for preparative separation of tyrosinase inhibitors from camellia pollen.
Authors:J. Chen, Q. Chen, F. Yu, H. Huang, P. Li, J. Zhu, and X. He
A rapid and sensitive method for the identification and quantification of phillyrin (POG) in Forsythia suspense is described. The phillyrin standard solution was directly infused into the ion trap mass spectrometers (IT-MS) for collecting the MSn spectra. The electrospray ionization (ESI) mass spectral fragmentation pathway of phillyrin was proposed, and the ESI-MSn fragmentation behavior of phillyrin was deduced in detail. The major product ion at m/z 355 belongs to furofuran, which was formed by loss the glucopyranoside (180 Da), and the characteristic fragment ions m/z 473, 395, 337, 309, and 249 were observed. The loss of 18 Da could arise from two different fragmentation pathways, and the observed ion was composed of a mixture of two different structural ions. Quantification of phillyrin was assigned in positive-ion mode at a product ion at m/z 557 → 355 by liquid chromatography-mass spectrometry (LC-MS). The LC-MS method was validated for linearity, sensitivity, accuracy, and precision and then used to determine the content of the phillyrin. Lastly, the LC-MS method was successfully applied to determine phillyrin in real sample F. suspense and three of its medicinal preparations in the positive mode at the first time.
Authors:X. Zhang, Y. Chen, Y. Wei, W. Lu, H. Liao, Y. Liu, X. Yang, X. Li, L. Yang, L. Li, and R. Li
Partial abortion of gametes possessing
genotype at locus
is responsible for hybrid sterility between indica and japonica subspecies in rice (
L.), while a single wide compatibility (WC) allele
can restore normal hybrid fertility between the two groups. In this study, Pei’ai 64S, one of the most popular WC line widely used for subspecific hybrid rice breeding program in South China was studied for location of its
locus. Twenty SSR (Simple Sequence Repeat) markers derived from Cornell SSR linkage map and 9 developed using sequences from GenBank database were employed to perform bulked segregant analysis of the mapping population derived from a three-way cross (Pei’ai 64S/T8//Akihikari) to tag fine location of the hybrid sterility locus,
locus was mapped on chromosome 6 approximately 0.2 cM from GXR6 and RM276 SSR markers. This tight linkage of the markers and the S-5 locus would be very useful for efficient marker-assisted selection for WC varieties and for map-based cloning of the gene.
Authors:H. Bai, X. Jin, F. Wang, J. Du, Y. Liu, and D. Chen
The preparation of a cold kit was introduced in the paper, and the effective quantities of the components (Vc, HEDP and SnCl2·2H2O) in the kit were determined. At the sametime, the effects of labelling kit on the reaction time, reaction temperature and animal distribution were studied in detail. The initial animal experiment showed the high uptake in the skeletal tissue, the clearance in the blood was quick.
Authors:L. Fu, Y. Chen, H. Du, J. Mao, X. Shi, and S. Li
A novel double -diketone 1,6-bis(1-phenyl-3-methyl-5-oxo-pyrazol-4-yl) hexanedione-[1,6] (BPMOPH) was further studied on its coordination compounds with uranium and thorium, respectively. The IR, UV, and1H-NMR spectra were examined, and the proposed structure is discussed.
Authors:Z. Cheng, Q. Lin, X. Jin, F. Wang, H. Bai, D. Chen, H. Fan, and J. Du
DTPA-Octreotide(Pentetreotide), a somatostatin analogue which can bind specifically and with high affinity to somatostatin
receptor in vitro and vivo, labeled with99mTc by tin reduction in acetate buffer, has been characterized by Reverse-phase High performance Liquid Chromatography. The
effect of different solvents, mobile phase pH, linear gradient and the injected volume on the separation efficiency was evaluated.
The results show that the separation efficiency is best using μBondapak-C18 (300×3.9 mm2), linear gradient of 40% to 80% methanol (1.0 ml/min) in 0.05M acetate buffer (pH 5.5) over a 30 min period and maintaining
for another 10 min. The labeled product is a mixture which mainly consists of five components (a, b, c, d, e) successfully
proved by HPLC. Paper chromatography is also evaluated in this paper. It may be used to determine the radiochemical purity
of the labeling product, but is not a good choice for the verification each components.
Authors:S. Chen, X. Meng, Q. Shuai, B. Jiao, S. Gao, and Q. Shi
solid complex Eu(C5H8NS2)3(C12H8N2) has been obtained from reaction of
hydrous europium chloride with ammonium pyrrolidinedithiocarbamate (APDC)
and 1,10-phenanthroline (o-phen⋅H2O)
in absolute ethanol. IR spectrum of the complex indicated that Eu3+
in the complex coordinated with sulfur atoms from the APDC and nitrogen atoms
from the o-phen. TG-DTG investigation provided
the evidence that the title complex was decomposed into EuS.
enthalpy change of the reaction of formation of the complex in ethanol, ΔrHmθ(l), as –22.2140.081 kJ mol–1,
and the molar heat capacity of the complex, cm,
as 61.6760.651 J mol–1 K–1,
at 298.15 K were determined by an RD-496 III type microcalorimeter. The enthalpy
change of the reaction of formation of the complex in solid, ΔrHmθ(s), was calculated as 54.5270.314 kJ mol–1
through a thermochemistry cycle. Based on the thermodynamics and kinetics
on the reaction of formation of the complex in ethanol at different temperatures,
fundamental parameters, including the activation enthalpy (ΔH≠θ),
the activation entropy (ΔS≠θ),
the activation free energy (ΔG≠θ),
the apparent reaction rate constant (k),
the apparent activation energy (E), the
pre-exponential constant (A) and the reaction
order (n), were obtained. The constant-volume
combustion energy of the complex, ΔcU,
was determined as –16937.889.79 kJ mol–1
by an RBC-II type rotating-bomb calorimeter at 298.15 K. Its standard enthalpy
of combustion, ΔcHmθ,
and standard enthalpy of formation, ΔfHmθ,
were calculated to be –16953.379.79 and –1708.2310.69
kJ mol–1, respectively.
Authors:Y. Guo, S. Luan, Y. Chen, X. Zang, Y. Jia, G. Zhong, and S. Ruan
New hexamethylenetetramine complexes of antimony and bismuth trichloride were synthesized through a solid phase reaction of
hexamethylenetetramine and antimony or bismuth trichloride. The formula of the complex is MCl3(C6H12N4)2⋅H2O (M=Sb, Bi).The crystal structure of the complexes belongs to monoclinic system and the lattice parameters: a=1.249 nm, b=1.4583 nm, c=1.6780 nm andβ=91.78 for SbCl3(C6H12N4)2⋅H2O and a=1.3250 nm, b=1.3889 nm, c=1.7449 nm and β=98.94 for BiCl3(C6H12N4)2⋅H2O. Far-infrared spectra reveal that the antimony or bismuth ion is coordinated by the nitrogen atom of the hexamethylenetetramine.
The thermal analysis also demonstrates the complex formation between the antimony or bismuth ion and hexamethylenetetramine.
The intermediate and final residues in the thermal decomposition process have been analyzed to check the pyrolysis reaction.
Authors:J. Zhang, L. Ge, X. Zhang, Y. Dai, H. Chen, and L. Mo
The thermal decomposition of Zn[NFA]2
5H2O (NFA=C16H18FN3O3, norfloxacin) and its kinetics were studied under non-isothermal conditions in air by TG-DTG and DTA methods. The intermediate and residue for each decomposition were identified from the TG curve. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The possible reaction mechanisms were investigated by comparing the kinetic parameters. The kinetic equation for the second stage can be expressed as d/dt=Aexp(–E/RT)(1–).
Authors:X. Chen, W. Feng, W. Miao, Y. Yu, Y. Shen, C. Wan, and J. Peng
The power-time curves of Tetrahymena thermophila exposed to tributyltin (TBT) were detected by microcalorimetry. Metabolic rate (r) decreased significantly while peak time
(PT) increased with the enhancement of TBT level. Compared with the measured multibiomarker including catalase, lactate dehydrogenase,
glutathione S-transferase, ATPase and membrane fluidity, PT and r could be sensitive biomarkers for assessing TBT toxicity at cellular level. The effective concentrations obtained by them
were consistent to those obtained by the protozoan community toxicity test. As a result, the microcalorimetric assay of T. thermophila had a great potential in assessing TBT acute toxicity and monitoring TBT pollution in the freshwater ecosystem.