Authors:G.-F. Shi, Z.-J. Wang, G.-Y. Wang, R.-X. Yao, F.-W. Chen, and Z.-R. Shi
High-performance liquid chromatography-mass spectrometry (HPLC-MS) method coupled with radical reaction for screening active ingredients from perennial fujimoto bean whole herb was established. The active ingredients, present in perennial fujimoto bean whole herb, possess scavenging effects towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide, peroxy radical, and hydroxyl radical. The radical scavenging abilities of these active ingredients were evaluated based on the relative peak areas in the HPLC chromatogram. The results indicate that potent antioxidants are present in the anhydrous methanol extract of perennial fujimoto bean whole herb. Based on HPLC-MS analysis, it was found that the scavenging ability can be mostly attributed to the presence of three compounds: cyanidin-3-o-β-d-glucopyranoside, troxerutin, and rutin. The structures were identified based on the MS and nuclear magnetic resonance (NMR) data. Free radical scavenging activity decreased in the following order: troxerutin > rutin > cyanidin-3-o-β-d-glucopyranoside.
Authors:B. Tong, Z. Tan, X. Lv, L. Sun, F. Xu, Q. Shi, and Y. Li
The molar heat capacities Cp,m of 2,2-dimethyl-1,3-propanediol were measured in the temperature range from 78 to 410 K by means of a small sample automated
adiabatic calorimeter. A solid-solid and a solid-liquid phase transitions were found at T-314.304 and 402.402 K, respectively, from the experimental Cp-T curve. The molar enthalpies and entropies of these transitions were determined to be 14.78 kJ mol−1, 47.01 J K−1 mol− for the solid-solid transition and 7.518 kJ mol−1, 18.68 J K−1 mol−1 for the solid-liquid transition, respectively. The dependence of heat capacity on the temperature was fitted to the following
polynomial equations with least square method. In the temperature range of 80 to 310 K, Cp,m/(J K−1 mol−1)=117.72+58.8022x+3.0964x2+6.87363x3−13.922x4+9.8889x5+16.195x6; x=[(T/K)−195]/115. In the temperature range of 325 to 395 K, Cp,m/(J K−1 mol−1)=290.74+22.767x−0.6247x2−0.8716x3−4.0159x4−0.2878x5+1.7244x6; x=[(T/K)−360]/35. The thermodynamic functions HT−H298.15 and ST−S298.15, were derived from the heat capacity data in the temperature range of 80 to 410 K with an interval of 5 K. The thermostability
of the compound was further tested by DSC and TG measurements. The results were in agreement with those obtained by adiabatic
Authors:F. Zhang, W. Feng, J. Shi, M. Wang, Y. Huang, W. He, and Z. Chai
The damage in the pup rat brain with low-level mercury exposure, and the concentration variation of trace elements in the
rat hippocampus was determined by synchrotron radiation X-ray fluorescence technique (SRXRF). Meanwhile, the levels and activities
of glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA)
in the hippocampus were also measured. The results showed that the low dose of inorganic mercury prenatal and postnatal exposure
could lead to the significant increase of both copper and zinc contents and remarkable decrease of iron content in pup rat
brain. Compared to the control group, the activities of antioxidant enzymes such as GSH-Px, SOD, the contents of GSH and MDA
in the pup rat hippocampus of mercury-exposed group fell down obviously.
Authors:Z. Wu, F. Li, L. Huang, Y. Shi, X. Jin, S. Fang, K. Chuang, R. Lyon, F. Harris, and S. Cheng
The thermal mechanical properties and degradation behaviors were studied on fibers prepared from two high-performance, heterocyclic polymers, poly(p-phenylenebenzobisthiazole) (PBZT) and poly(p-phenylenebenzobisoxazole) (PBZO). Our research demonstrated that these two fibers exhibited excellent mechanical properties and outstanding thermal and thermo-oxidative stability. Their long-term mechanical tensile performance at high temperatures was found to be critically associated with the stability of the C—O or C—S linkage at the heterocyclic rings on these polymers' backbones. PBZO fibers with the C—O linkages displayed substantially higher thermal stability compared to PBZT containing C—S linkages. High resolution pyrolysis-gas chromatography/mass spectrometry provided the information of the pyrolyzates' compositions and distributions as well as their relationships with the structures of PBZT and PBZO. Based on the analysis of the compositions and distributions of all pyrolyzates at different temperatures, it was found that the thermal degradation mechanisms for both of these heterocyclic polymers were identical. Kevlar®-49 fibers were also studied under the same experimental conditions in order to make a comparison of thermo-oxidative stability and long-term mechanical performance at high temperatures with PBZO and PBZT fibers. The data of two high-performance aromatic polyimide fibers were also included as references.
Authors:Y. C. Xiao, L. T. Liu, J. J. Bian, C. Q. Yan, L. Ye, M. X. Zhao, Q. S. Huang, W. Wang, K. Liang, Z. F. Shi, and X. Ke
Shuganjieyu (SGJY) capsule is a classical formula widely used in Chinese clinical application. In this paper, an ultra-performance liquid chromatography coupled with electrospray ionization and ion trap mass spectrometry has been established to separate and identify the chemical constituents of SGJY and the multiple constituents of SGJY in rats. The chromatographic separation was performed on a C18 RRHD column (150 × 2.1 mm, 1.8 μm), while 0.1% formic acid–water and 0.1% formic acid–acetonitrile was used as mobile phase. Mass spectral data were acquired in both positive and negative modes. On the basis of the characteristic retention time (Rt) and mass spectral data with those of reference standards and relevant references, 73 constituents from the SGJY and 15 ingredients including 10 original constituents and 5 metabolites from the rat plasma after oral administration of SGJY were identified or tentatively characterized. This study provided helpful chemical information for further pharmacology and active mechanism research on SGJY.