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Gan L.-S.,Zhejiang University | Zheng D.-J.,Zhejiang University | Liu Q.,Zhejiang University | Zhou J.,Zhejiang University | And 5 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2015

Fourteen 20,24-epoxy-cycloartane triterpenoids, including eight new ones (1-8), were isolated from 95% ethanol extract of the rhizomes of Beesia calthifolia. Their structures were determined by spectroscopic and chemical methods, especially 2D NMR and HRMS techniques. Among them, four new compounds (1-4) possess carbonyl groups at C-16, which were rarely found in cycloartane triterpenoids from this genus. Relative configuration at C-12 in beesioside III (9) and its aglycone (10) was revised to be 12α-OH rather than the reported 12β-OH. Some of the compounds showed potential hepatoprotective activities against human hepatic L02 cell damage induced by D-galactosamine. © 2015 Elsevier Ltd.

Niu H.,Zhejiang University of Technology | Li L.,Zhejiang University of Technology | Li Y.,Zhejiang University of Technology | Guo L.,Zhejiang Chemical Industry Research Institute Co. | And 3 more authors.
Cuihua Xuebao/Chinese Journal of Catalysis | Year: 2013

The effect of Cr-doping on the acidity and pore structure of mesoporous magnesium fluoride prepared by co-precipitation was investigated. The prepared MgF2, CrF3, and Cr(x)-MgF2 with different Cr loadings were characterized by N2 adsorption-desorption, X-ray powder diffraction, transmission electron microscopy, pyridine adsorption Fourier transform infrared spectroscopy, and NH3 temperature-programmed desorption. The catalytic activity of MgF2 and Cr(x)-MgF2 was tested in the disproportionation of CHClF2. The doped Cr in the MgF2 results in the improvements of the specific surface area and surface Lewis acidity. Meanwhile, the MgF2 catalyst samples doped with Cr show excellent catalytic performance in CHClF2 disproportionation. © 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Zeng L.-W.,Zhejiang University | Zhou C.-X.,Zhejiang University | Liu J.-D.,Nanjing University | Liu C.-H.,Nanjing University | And 5 more authors.
Natural Product Research | Year: 2016

Sixteen new ester derivatives with various partition coefficient (ClogP) values of tanshinone IIA (TSIIA), a major lipophilic component of Salvia miltiorrhiza, were designed and synthesised, including six aliphatic esters (3a–e, 5a), one phosphate ester (4c) and nine aromatic esters (5b–j). Their antimicrobial activities against three Gram-positive bacteria strains, Staphylococcus aureus, Bacillus subtilis, and Bacillus amyloliquefaciens, and two Gram-negative bacteria strains, Pseudomonas aeruginosa and Escherichia coli, as well as two fungi species, Candida albicans and Saccharomyces cerevisiae, were evaluated in vitro by broth microdilution susceptibility tests. The results showed that keeping ClogP values in a certain range is necessary for their antimicrobial activities. For those compounds with ClogP values between 5 and 10, their MIC values showed positive correlations with ClogP values. In particular, compound 3e exhibited fourfold and twofold higher potency than the standard drug amphotericin B against fungi C. albicans and S. cerevisiae with MIC values of 1.95 and 7.81 μg/mL, respectively. © 2016 Taylor & Francis

Wang X.-J.,Zhejiang University | You J.-Z.,Zhejiang University | Yu F.,Zhejiang Chemical Industry Research Institute Co.
Journal of Analytical and Applied Pyrolysis | Year: 2015

The thermal decomposition of emtricitabine (FTC) was measured with thermogravimetry (TG), differential scanning calorimetry (DSC), and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG-FTIR). The infrared (IR) spectra, high performance liquid chromatography (HPLC), and liquid chromatography mass spectrometry (LC-MS) of FTC and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated with an ab initio method from the GAMESS program. The mechanism of thermal decomposition of FTC was discussed. The kinetic parameters of thermal decomposition such as activation energy Ea and the pre-exponential factor A were obtained with the Ozawa method. The prospective lifetime of FTC was estimated with the Dakin equation. The results indicated that the thermal decomposition of FTC is a two-step process. In the thermal decomposition process, most of FTC decomposes directly to small molecules and insoluble substance due to the fracture of the N-C bond of amide in the 5-fluorocytosine ring, a small amount of FTC decomposes to 5-fluorocytosine due to the fracture of the N-glycosidic bond, and a small amount of 5-fluorouracil and 2′,3′-dideoxy-5-fluoro-3′-thiauridine are generated due to the oxidation reaction. The initial decomposition temperature either nitrogen or air is 200 °C. For decomposition in nitrogen, the Ea and A for the initial thermal decomposition are 142.4 kJ mol-1 and 2.09 × 1013 min-1, respectively. For decomposition in air, the corresponding Ea and A are 140.7 kJ mol-1 and 1.62 × 1013 min-1, respectively. The thermal stability of FTC is very good under routine temperatures. © 2015 Elsevier B.V. All rights reserved.

Zheng D.-J.,Zhejiang University | Zhou J.,Zhejiang University | Liu Q.,Zhejiang University | Yao W.,Zhejiang Chemical Industry Research Institute Co. | And 5 more authors.
Fitoterapia | Year: 2015

Abstract Phytochemical study on rhizomes of Beesia calthifolia resulted in the isolation of five new (1-5) and three known (6-8) cycloartane triterpenoids possessing a hemiketal or ketal group at C-24 from the EtOAc fraction of 95% ethanol extract. Their structures were determined by spectroscopic and chemical methods, especially HRMS and 2D NMR techniques. Compounds 3 and 4 showed potential hepatoprotective activities against d-galactosamine induced human hepatic L02 cell damage. © 2015 Elsevier B.V.

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