This study aims to develop and validate a high-performance size-exclusion chromatography (HPSEC) method to determine the amount of polymer in cefmetazole sodium for injection and to compare this method with gel chromatography. A Zenix SEC-150 column was used with the mobile phase of phosphate buffer solution (pH 7.0; 0.01 M)—acetonitrile (90:10 v/v) at a flow rate of 0.8 mL min−1 and a detection wavelength of 240 nm. The polymer was quantified by an external standard method with self-control, and the amount was expressed by the percentage of cefmetazole. The HPSEC method was validated for specificity, linearity, and precision. The chromatographic conditions, chromatographic performances, sensitivity, linearity, and precision of the developed HPSEC method and gel chromatography were compared, and both methods were subsequently used to determine the amount of polymer from seven batches of samples. The HPSEC method was fully validated. The time of isocratic elution for sample assay was less than 14 min. The results of comparison indicate that the developed HPSEC method was superior to gel chromatography. The Student t test results also showed significant difference in the amount of polymer from the samples obtained by the two methods. Thus, the HPSEC method with two obvious advantages, the superior sensitivity and a shorter analysis time, is more suitable for determination of polymer amount in cefmetazole sodium for injection to control the quality of the product.
In this study, the peach kernel proteins were extracted and treated with alkaline proteinase to generate peach kernel protein hydrolysate (PKH), which showed angiotensin converting enzyme (ACE) inhibition activity. The hydrolysate was separated into four fractions and their anti-ACE activities were investigated. Our results showed that all PKHs had anti-ACE activity, and the lowest molecular weight fraction PKH4 had the highest ACE inhibitory activity. Lineweaver–Burk plots illustrated that the inhibition types of PKH3 and PKH4 were non-competitive. The Ki of PKH4 was lower than Ki of PKH3; suggesting PKH4 had high affinity to ACE. Amino acid composition analysis showed that the best anti-ACE peptide PKH4 possessed high levels of hydrophobic amino acids, branched-chain amino acids, and aromatic amino acids. In summary, our findings demonstrated that high anti-ACE activity is negatively related to the size of the PKHs and possibly the composition of amino acids, and the PKH4 was the best ACE inhibitor. Further, peach kernel peptides can be developed as a functional food for patients with hypertension.
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:G. Zhong, S. Luan, P. Wang, Y. Guo, Y. Chen and Y. Jia
thiourea complexes of antimony and bismuth triiodide were synthesized by a
direct reaction of antimony and bismuth triiodide with thiourea powder at
room temperature. The formula of the complex is MI3[SC(NH2)2]3(M=Sb, Bi). The crystal structure of the
complexes belongs to monoclinic system and the lattice parameters are a=1.4772 nm, b=1.6582
nm, c=2.0674 nm and β=90.81 for
and a=1.4009 nm, b=2.0170
nm, c=2.0397 nm and β=90.84 for
The infrared spectra reveal that the trivalent antimony or bismuth ion is
coordinated by the nitrogen atom, not the sulfur atom of the thiourea. Thermal
analysis shows that there are two times structure rearrangements or phase
transformation in the complexes from 100 to 170C.
Authors:Q. Ren, Y. Hua, H. Shen, L. Zhong, C. Jin, Y. Mi, H. Yao, Y. Xie, S. Wei and L. Zhou
The uptake of rare earth elements (REE) by Euglena gracilis cells has been investigated in Fudan University. The remarkable ability to transport REEs to these cell’s compartments had
been observed. X-ray absorption fine structure experiments (XAFS) of cerium in Euglena gracilis were performed at Beijing Synchrotron Radiation Facility (BSRF) to directly determine the cerium valence state and coordination
structure in situ. Extended X-ray absorption fine structure (EXAFS) derived calculation showed that cerium was surrounded
by 8 N atoms with bond length of 0.258 nm. Combining with other measurements, it may indicate that most likely REEs are mainly
located in chlorophyll molecules.
Authors:G. Zhong, J. Shen, Q. Jiang, Y. Jia, M. Chen and Z. Zhang
Four ethylenediamine-N,N,N′,N′-tetraacetate complexes with Sb(III)-M-Sb(III) polynuclear structure (M=Co(II), La(III), Nd(III), Dy(III)) are synthesized. [Sb2-μ4-(EDTA)2Co(H2O)2]·5.15H2O is characterized by single crystal X-ray diffraction. The crystal structure of [Sb2-μ4-(EDTA)2Co(H2O)2]·5.15H2O belongs to monoclinic system, space group P21/n, lattice parameters: a=6.9969(2), b=20.8705(4), c=10.8106(2) Å, β=90.031(1)°, V=1578.66(6) Å3, Z=2, Mr=1007.76, Dc=2.120 g cm−3, F(000)=1001, μ=2.323 mm−1, the final R=0.0235 and wR=0.0629 for 3480 observed reflections (I>2σ(I)). The powder X-ray diffraction patterns of the complexes are also measured. Elemental analyses, FTIR spectra, TG-DSC and
DTA of [Sb2(EDTA)2Ln]NO3·nH2O are performed. FTIR spectra reveal that the antimony and other metallic ions were connected through the carboxylate bridges.
The thermal analysis can demonstrate the complex formation of the antimony, other metallic ions and EDTA. The possible pyrolysis
reactions in the thermal decomposition process of the complexes, the experimental and calculated percentage mass losses are
Authors:Y. Masuda, K. Minagawa, W. Morita, Z. Zhong and P. K. Gallagher
The behaviour of thermal dehydrations of isomorphous complexes of calcium copper acetate hexahydrate, CaCu(CH3CO2)4·6H2O and calcium cadmium acetate hexahydrate, CaCd(CH3CO2)4· 6H2O was studied by means of thermal analyses and X-ray structural analysis. The enthalpy changes for the dehydration of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 315±9.7 and 295±8.0 kJ mol−1, respectively. The DSC curves of the dehydrations indicated that the seemingly simple dehydrations are more complex than they appear at first sight. Apparent activation energies for the dehydrations of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 85.7±7.4 and 87.9±12.5 kJ mol−1, respectively.
Authors:F. Xu, L. Sun, P. Chen, Y. Qi, J. Zhang, J. Zhao, Y. Liu, L. Zhang, Zhong Cao, D. Yang, J. Zeng and Y. Du
The heat capacities of LiNH2 and Li2MgN2H2 were measured by a modulated differential scanning calorimetry (MDSC) over the temperature range from 223 to 473 K for the
first time. The value of heat capacity of LiNH2 is bigger than that of Li2MgN2H2 from 223 to 473 K. The thermodynamic parameters such as enthalpy (H–H298.15) and entropy (S–S298.15) versus 298.15 K were calculated based on the above heat capacities. The thermal stabilities of them were investigated by
thermogravimetric analysis (TG) at a heating rate of 10 K min−1 with Ar gas flow rate of 30 mL min−1 from room temperature to 1,080 K. TG curves showed that the thermal decomposition of them occurred in two stages. The order
of thermal stability of them is: Li2MgN2H2 > LiNH2. The results indicate that addition of Mg increases the thermal stability of Li–N–H system and decrease the value of heat
capacities of Li–N–H system.
Authors:J. L. Zhao, L. Zou, L. Y. Zhong, L. X. Peng, P. L. Ying, M. L. Tan and G. Zhao
This study was to examine the effects of four fungal polysaccharides, namely exo-polysaccharide (EPS), water-extracted mycelia polysaccharide (WPS), sodium hydroxideextracted mycelia polysaccharide (SPS), and hydrochloric-extracted mycelia polysaccharide (APS) obtained from the endophytic fungus Bionectra pityrodes Fat6, on the sprout growth and flavonoids production of Fagopyrum tataricum. Without obvious changes in the appearance of the sprouts, the exogenous polysaccharide elicitors notably stimulated the sprout growth and functional metabolites accumulation, and the stimulation effect was mainly depended on the polysaccharide species along with its treatment dose. With application of 150 mg/l of EPS, 150 mg/l of WPS and 200 mg/l of SPS, the total rutin and quercetin yield of buckwheat sprouts was effectively increased to 49.18 mg/(100 sprouts), 50.54 mg/(100 sprouts), and 52.27 mg/(100 sprouts), respectively. That was about 1.57- to 1.66-fold in comparison with the control culture of 31.40 mg/(100 sprouts). Moreover, the present study revealed the accumulation of bioactive flavonoids resulted from the stimulation of the phenylpropanoid pathway by fungal polysaccharide treatments. It could be an efficient strategy for improving the nutritional and functional quality of tartary buckwheat sprouts applied with specific fungal elicitors.
Authors:J. Chen, L. Wang, W.H. Liu, J. Shi, Y. Zhong, S.J. Liu and S.M. Liu
Although the use of aspirin has substantially reduced the risks of cardiovascular events and death, its potential mechanisms have not been fully elucidated. In a previous study, we found that aspirin triggers cellular autophagy. In the present study, we aimed to determine the protective effects of aspirin on human coronary artery endothelial cells (HCAECs) and explore its underlying mechanisms. HCAECs were treated with oxidized low-density lipoprotein (ox-LDL), angiotensin II (Ang-II), or high glucose (HG) with or without aspirin stimulation. The expression levels of endothelial nitric oxide (NO) synthase (eNOS), p-eNOS, LC3, p62, phosphor-nuclear factor kappa B (p-NF-κB), p-p38 mitogen-activated protein kinase (p-p38 MAPK), and Beclin-1 were detected via immunoblotting analysis. Concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured via ELISA. NO levels were determined using the Griess reagent. Autophagic flux was tracked by tandem mRFP-GFP-tagged LC3. Results showed that aspirin increased eNOS level and reduced injury to the endothelial cells (ECs) caused by ox-LDL, Ang-II, and HG treatment in a dose-dependent manner. Aspirin also increased the LC3II/LC3I ratio, decreased p62 expression, and enhanced autophagic flux (autophagosome and autolysosome puncta) in the HCAECs. p-NF-κB and p-p38 mitogen-activated protein kinase inhibition, sVCAM-1 and sICAM-1 secretion, and eNOS activity promotion by aspirin treatment were found to be dependent on Beclin-1. These results suggested that aspirin can protect ECs from ox-LDL-, Ang-II-, and HG-induced injury by activating autophagy in a Beclin-1-dependent manner.