Table of Content

15 September 1998, Volume 7 Issue 3

Previous Issue    Next Issue

Full Papers

Modeling of Dopamine D2 Receptor and its Agonist DOCK Analyses

Qi-Qing Zhu, Zong-Ru Guo^*

1998, 7(3):  115-120. 

Asbtract ( 883 )   PDF (415KB) ( 438 )  

References | Related Articles | Metrics

A model of transmembrane helices of dopamine D2 receptor was constructed using the X-ray coordinates of bacteriorhodopsin (BR) as a template. Based on the results from the model and the sitedirected mutagenesis experience, the binding pocket, including nine amino acid residues beside indispensable Asp86, Ser141 and Ser144 residues, was defined. In order to testify the 3D-structure of dopamine D2 receptor and specially test the binding sites, two sets of D2 receptor agonists (one was rigid and the other flexible) were selected for docking. A good result of correlation between -logIC50 and binding energy Eb indicates that the predicted model is reliable for the investigation of the receptor-ligand interaction and design of new active molecules.

Interactions Between Anticancer Pt(II) complexes and Human Erythrocyte Spectrin

Xiao-Gai Yang, Rong-Chang Li

1998, 7(3):  121-126. 

Asbtract ( 1172 )   PDF (318KB) ( 491 )  

References | Related Articles | Metrics

The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10² binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K1>3.47×10⁶ were of highest affinity, 1.8×10² sites with K2 = 3.47×10⁶ were of high affinity, and other 2.2×10² sites with K3 = 8.77×10⁵ were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio (R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis-diaquodiamine platinum (DADP) with SP followed a twostep first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2-cyclohexanediammine isomers as chiral carrier ligand, stereo-matching played a more important role than the affinity of Pt(II) to thiol groups of SP.

Antiplatelet Aggregation Effects of YIGSK and RGD Containing Peptides

Dilinur Shabitofu, Ming Zhao, Chao Wang, Shi-Qi Peng^*

1998, 7(3):  127-129. 

Asbtract ( 1159 )   PDF (289KB) ( 481 )  

References | Related Articles | Metrics

Antiplatelet aggregation effects of YIGSK, RGDS, RGDV, RGDF, YIGSKRGDS, YIGSKRGDV and YIGSKRGDF were observed. By comparing their activities it was found that by coupling YIGSK and RGD containing peptides the antiplatelet aggregation effects of some of the compounds may be enhanced.

Methodological Studies on Genomic DNA Extraction and Purification from Plant Drug Materials

Hui Cao, Paul Pui-Hay But, Pang-Chui Shaw

1998, 7(3):  130-137. 

Asbtract ( 949 )   PDF (1059KB) ( 726 )  

References | Related Articles | Metrics

This paper reports the rationale and methods of DNA extraction and purification from nine species of Compositae and four commercial drugs of corresponding plant Elephantopus scaber. The comparison of three methods: CsCl gradient, CTAB/CsCl gradient and CTAB miniprep extraction by yield, purity and factors affecting PCR was carried out. In conclusion, CTAB miniprep method provides a rapid, effective, economic approach for isolating genomic DNA for Chinese drug identification by genomic fingerprints.

Quantitative Analysis of Flavonoids in Scutellariae Radix of Different Sources and Seasonal Variation by HPLC

Yong-Yu Zhang, Yun-Zhen Guo, Hiroyuki Ageta, Yoshihiro Harigaya, Masayuki Onda, Kadsunori Hashimoto, Yukinobu Ikeya, Minoru Okada, Masao Maruno

1998, 7(3):  138-141. 

Asbtract ( 853 )   PDF (301KB) ( 523 )  

References | Related Articles | Metrics

The seasonal and source variations of flavonoid contents in Scutellariae Radix were investigated by using the materials collected at the same place in Liaoning Province, China, during three years, 1990-1992, and in seven other provinces in China. Four principal flavonoids in the plant roots, i.e., baicalin, baicalein, wogonin-7-O-glucuronide and wogonin were analyzed by using a reversed-phase chromatographic system with a chemically bonded ODS silica gel column and phosphate buffer-methanol (68:32 and 1:1) as mobile phase. The contents of the four compounds combined in the herb collected at Chengde, Hebei Province are the highest. The results show that the best time for harvesting the roots in Liaoning Province is the end of August.

The Activity of Erianin and Chrysotoxine from Dendrobium chrysotoxum to Reverse Multidrug Resistance in B16/h MDR-1 Cells

Guo-Xiang Ma^*, Gerald A. LeBlanc

1998, 7(3):  142-146. 

Asbtract ( 319 )   PDF (302KB) ( 530 )  

References | Related Articles | Metrics

The ability of two dihydrostilbene derivatives erianin and chrysotoxine from Dendrobium chrysotoxum to reverse multidrug resistant (MDR) cells was investigated using murine B16 melanoma cells transfected with the human MDR-1 gene and crossresistant to vinblastine and adriamycin (B16/h MDR-1 cells). Both of the two compounds were shown to increase the accumulation of adriamycin, the P-glycoprotein (P-gp) substrate, in B16/h MDR-1 transfectants.

Cytotoxicity of Benzo(a)pyrene-7,8-dihydrodiol on Genetically Engineered V79 Chinese Hamster Cells Expressing Rat Liver Cytochrome P450 1A1

Jing-Rong Cui, N.P.E.Vermeulen

1998, 7(3):  147-151. 

Asbtract ( 809 )   PDF (314KB) ( 490 )  

References | Related Articles | Metrics

To develop well defined in vitro cell system to test cytotoxicity of a number of model toxins, genetically engineered V79 Chinese hamster fibroblasts expressing isoenzymes of cytochrome P4501A1 XEM2 cells and V79 cells (parental), which lack cytochrome P450 enzyme activities, were used as controls. The cytotoxic effect of trans 7,8 dihydrbenzo(a)pyrene (BP-7,8-diol) on the parental cells V79 and V79 derived XEM2 cells were evaluated by two methods for cell viability. The data obtained expressed that BP-7,8-diol ranging from 1.0 μmol·L^-1 to 5.0 μmol·L^-1 in concentrations incubated for 24 h showed a strong cytotoxic effect in XEM2 cells (expressing rat cytochrome P4501A1) in a concentration dependent manner. Time dependent decrease for survival of XEM2 cells was also observed at 2.5 μmol·L^-1 concentration. Likewise, BP-7,8-diol did not alter the survival of the parental cells V79 under the same condition. This study also showed that α naphthoflavone (αNF), a well known inhibitor of cytochrome P4501A1 might alter BP-7,8-diol induced cytotoxicity in the XEM2 cells. Our results suggested that cytochrome P4501A1 is responsible for BP-7,8-diol induced cytotoxicity.

Protective Actions of Blumea Flavanones on Primary Cultured Hepatocytes and Liver Subcellular Organelle against Lipid Peroxidation

Jin-Hua Zhao, Shi-Bo Xu^*, Zheng-Lian Wang, Yong-Cheng Lin, Rong-Li Chen

1998, 7(3):  152-156. 

Asbtract ( 874 )   PDF (304KB) ( 553 )  

References | Related Articles | Metrics

To search for the protective actions of blumea flavanones (BFs) on hepatocytes and hepatic subcellular organelle against lipid peroxidation, monkey's hepatocytes were isolated and cultured with or without blumea flavanones, then damaged by FeSO4-cysteine or CCl4. The lipid peroxidation (malondialdehyde production) and alteration in hepatocyte membrane (leakage of GPT) were estimated. Hepatic subcellular organelles were also isolated and incubated with or without blumea flavanones, then injured by FeSO4-ascorbate. The generation of malondialdehyde(MDA) was measured. It was found that BFs 10 and 100 μmol·L^-1 inhibited the MDA generation and GPT (glutamic pyruvic transaminase) leakage out of hepatocytes that were induced by CCl4 or FeSO4-cysteine. BFs could prevent lipid peroxidation initiated by FeSO4-ascorbate in subcellular organelle suspension. Among BFs, BF-possessed the strongest activity. Conclusion: Blumea flavanones possess antioxidation activities that protect monkey's hepatocytes and hepatic subcellular organelle against injuries induced by FeSO4 or CCl4.

The Effects of Etimicin and Gentamicin on Renal Endoplasmic Reticulum ⁴⁵Ca²⁺-Uptake and Ca²⁺-Mg²⁺-ATPase Activity

Zhong-Dong Li, Wen-Qing Hong, Pei-Zhong Li

1998, 7(3):  157-160. 

Asbtract ( 818 )   PDF (301KB) ( 472 )  

References | Related Articles | Metrics

Objective: To study the effects of etimicin (EM) and gentamicin (GM) on renal endoplasmic reticulum ⁴⁵Ca²⁺ uptake and Ca²⁺-Mg²⁺-ATPase activity. Methods: Using ⁴⁵Ca²⁺ incorporation technique and peacock blue spectrophotometry respectively. Results: EM and GM (≥3.4×10^-4 mol·L^-1) inhibited endoplasmic reticulum ⁴⁵Ca²⁺-uptake (the rate of inhibition: ≥17.4% and ≥25.5%, respectively); EM and GM (3.4×10^-2 mol·L^-1) inhibited Ca²⁺-Mg²⁺-ATPase activity (the rate of inhibition: 24.2% and 29.2%, respectively). Conclusion: At high concentration, EM and GM elevated intracellular calcium which may be related to their nephrotoxicity.

Communications

Carbon and Proton NMR Assignments for 2-Hydroxy-3,4,6,7-tetramethoxy-9,10-dihydrophenanthrene

Wen-Kui Li, Jing-Qi Pan, Ru-Yi Zhang, Pei-Gen Xiao

1998, 7(3):  161-163. 

Asbtract ( 1278 )   PDF (289KB) ( 515 )  

References | Related Articles | Metrics

Study of Plastids in Fritillaria thunbergii Miq.

Wen-Yan Gao, Pong-Zhao Fu, Zhi-Liang, Pei-Gen Xiao

1998, 7(3):  164-168. 

Asbtract ( 1247 )   PDF (444KB) ( 449 )  

References | Related Articles | Metrics

Semisynthesis of Strychnine N-oxide and Brucine N-oxide

Bao-Chang Cai, Hao Wu, Tian-Shan Wang, Hirotsuqu Miyashiro, Masao Hattori

1998, 7(3):  169-170. 

Asbtract ( 869 )   PDF (289KB) ( 535 )  

References | Related Articles | Metrics