Density functional theory investigation on antioxidant activity of five flavonoids from Hebei Xiangju / 中国中药杂志

Five main flavonoids of Hebei Xiangju were studied using the Density Functional Theory (DFT) B3LYP method with 6-311 G (d) basis set．Their activities were analyzed based on molecular structure,bond dissociation energy (BDE),natural orbital charge distribution (NBO),bond order and the energy gap between HOMO and LUMO. The results showed that the existing of intra molecular hydrogen bond in B ring can improve the antioxidant activity of the flavonoids, at the same time, the hydroxyl groups on the glycosides do not have the activity of eliminating free radicals, but decrease the total molecular antioxidant activity. As a result, the antioxidant ability order of the five flavonoids compounds is luteolin< luteolin-7-O-glucoside< apigenin < acacetin < acacetin-7-O-glucose, which is agreement with the experimental conclusion reported in literature. The results showed that the DFT method can provide theoretical guidance for the selection of natural flavonoid antioxidants.

Construction of a eukaryotic expression plasmid containing gp120 gene of HIV-1 subtype B and its expression in HepG2 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct an eukaryotic expression plasmid containing gp120 gene of HIV-1 subtype B and obtain gp120 gene expression in HepG2 cells.</p><p><b>METHODS</b>According to the published gp120 gene sequence in Genbank, a pair of primers was designed and synthesized. The PCR amplification product of gp120 gene was cloned into pMD-18T vector using TA cloning followed by BamHI and XhoI digestion and sequence analysis. The target gene was then subcloned into a highly efficient eukaryotic expression vector pcDNA3.1 (+). The recombinant plasmid was sequenced and identified by restrictive endonuclease digestion, and transfected into HepG2 cells via liposome. The expression of gp120 gene was analyzed by RT-PCR and Western blotting, respectively.</p><p><b>RESULTS</b>Restriction endonuclease digestion and sequence analysis verified successful construction of the recombinant vector pcDNA3.1(+)/gp120. The target fragment gp120 was identical with U26942 in Genbank, and the expression of gp120 gene was detected in the lysate of the transfected HepG2 cells by RT-PCR and Western blotting.</p><p><b>CONCLUSION</b>The eukaryotic expression plasmid for gp120 has been constructed successfully, which is capable of stable expression in HepG2 cells.</p>

Investigations on the molecular mechanisms of saponins from Anemarrhena asphodeloides Bunge using oligonucleotide microarrays / 药学学报

<p><b>AIM</b>To investigate the molecular mechanisms of saponins from the rhizome of Anemarrhena asphodeloides Bunge.</p><p><b>METHODS</b>Oligonucleotide microarrays consisting of 87 probes representing 87 human cardiovascular disease-related genes were constructed. Effects of saponins on gene expression in human umbilical vein endothelial cells were analyzed by comparing hybridization of Cy 5-labeled cDNAs from saponins-treated human umbilical vein endothelial cells and Cy 3-labeled cDNAs from untreated human umbilical vein endothelial cells.</p><p><b>RESULTS</b>The results indicate that angiotensinogen gene, alpha 2A-adrenoceptor gene and endothelin-converting enzyme 1 gene were downregulated 2.8, 1.9 and 3.1 folds respectively after human umbilical vein endothelial cells were incubated in medium containing 80 mg.L-1 saponins.</p><p><b>CONCLUSION</b>These results suggest that saponins may have beneficial effect on cardiovascular diseases by modulating the function of vein endothial cells and microarray can be used to investigate the biological action of extracts from traditional Chinese medicine.</p>