Lan-Mei Chen

In vitro and in vivo investigations on the antiviral activity of a series of mixed-valence rare earth borotungstate heteropoly blues.

A series of mixed-valence rare earth borotungsto-heteropoly blues, K15H2[Ln(BW9W2O39)2].28H2O (Ln2, Ln=La, Ce, Pr, Nd, Sm, Eu, Gd), have been prepared and characterized by IR, UV, XPS, ESR and electrochemistry. The cytotoxicity and antiviral activity of these rare earth borotungstate heteropoly blues were investigated against influenza A(FluVA) strain (A/H1N1/Jingfang/1/91 and A/H3N2/Jingfang/30/95) and influenza virus B(FluVB) (B/Hufang/1/87) in MDCK cells. The results show that K15H2[Pr(BW9W2O39)2].28H2O (Pr2) exhibits the highest antiviral activity against FluVA with EC50 of less than 4.0 microg/ml (A/H1N1/Jingfang/1/91) and 6.0 microg/ml (A/H3N2/Jingfang/30/95), respectively, and has the lowest toxicity with CC50 of more than 480 microg/ml against MDCK cells. Additionally, both K15H2[Pr(BW9W2O39)2].28H2O (Pr2) and K15H2[Eu(BW9W2O39)2].28H2O (Eu2) showed excellent antiviral activities against FluVB by inhibiting FluVB replication at an EC50 of less than 8.0 microg/ml. Furthermore, investigation on in vivo antiviral activity of Pr2 against FluVA(FM1) in mice by giving the dosage either orally (p.o.) or intraperitoneally (i.p.), indicates that Pr2 exhibits higher inhibitory activity than that of positive control, virazole, and that its more effective when administered by i.p.

The hydrolysis process of the anticancer complex [ImH][trans-RuCl4(Im)2]: a theoretical study

A hydrolysis process of the anticancer drug [ImH][trans-RuCl4(Im)2] (ICR, Im=imidazole) has been investigated using density functional theory (DFT), and the aqueous solution effect has been considered and calculated by the conductor-like polarizable calculation model (CPCM). The stationary points on the potential energy surfaces for the first and second hydrolysis steps (including two different paths) were fully optimized and characterized. The results show that the computed values of free energy barriers DeltaG degrees (aq) and rate constants (k) in aqueous solution, in particular for the first hydrolysis step, are in excellent agreement with the experimental results. The analysis of electronic characteristics of species in the hydrolysis process suggests that the nucleophilic attack abilities (A) of hydrolysis products by biomolecular targets is in the sequence of A()<A()<A() (, and express the hydrolysis products of the first hydrolysis step, and of the second hydrolysis step through path 1 and path 2, respectively). On the basis of our present limited work, the following can reasonably be suggested: path 1 in the second hydrolysis step has thermodynamic preference over path 2, and thus the cis-diaqua species may dominate. The theoretical results provide the structural properties as well as the detailed energy profiles for the hydrolysis process of ICR, so such results may contribute to understanding the reaction mechanism of this drug with the biomolecular target.

Synthesis and physical properties of layered Ba(x)CoO

A layered cobaltite Ba(x)CoO2 (x = 0.19, 0.28, 0.30, 0.33) was synthesized by an ion exchange technique from the layered Na(x)CoO2 precursors. The phase composition and physical properties were investigated. Ba(x)CoO2 is isomorphic to the precursor Na(x)CoO2. The magnetic susceptibility of Ba(x)CoO2 decreases with increasing barium content and shows a Curie-Weiss-like behavior at temperatures above 50 K. The resistivity is sensitive to the barium content. As the barium content increases from 0.19 to 0.33, a crossover from a semiconducting behavior to a metallic behavior was observed. The Seebeck coefficient of Ba(x)CoO2 is insensitive to the barium content due to the tradeoff effect between the carrier concentration and the Co(4+) content, while the thermal conductivity increases with the increasing barium content from 0.19 to 0.33 owing to the ordered state of Ba ions between the CoO2 layers.