Computational investigation of the anti-HIV activity of Chinese medicinal formula Three-Huang Powder.

An essential step in the life cycle of human immunodeficiency virus type 1 (HIV-1) is integration of the double-stranded retroviral DNA into the genome of the host cell. HIV-1 integrase, the enzyme that inserts the vital DNA into the host chromosome, is an attractive and rational target for anti-AIDS drug design because it is essential for HIV replication and there are no known counterparts in the host cell. Inhibitors of this enzyme have the great potential to complement the therapeutic use of HIV protease and reverse transcriptase inhibitors. Natural products have provided a source of new drug candidates for anti-AIDS therapy. Baicalein and baicalin, identified components of a Chinese herbal medicine Scutellaria baicalensis Georgi, have been shown to inhibit infectivity and replication of HIV. They are therefore promising lead compounds for developing new anti-AIDS drugs. To understand how the inhibitors work and therefore design more potent and specific inhibitors, we have used molecular modeling techniques to investigate the binding modes of these inhibitors. The three-dimensional structures of these inhibitors were first built. Then, computational binding studies of these inhibitors, based on the crystal structure of the HIV-1 integrase catalytic domain, were performed to study the complex structure. The preliminary results of our computational modeling study demonstrated that Baicalein binds to the active site region of the HIV-1 integrase. Our study will be of help to identify the pharmacophores of inhibitors binding to HIV-1 integrase and design new pharmaceuticals for the treatment of AIDS.

[Terpenoids from leaves of Aeschynanthus mengxinensis].

OBJECTIVE: To study the chemical constituents from the ethyl acetate portion of an ethanolic extractive of the leaves of Aeschynanthus mengxinensis. METHOD: The column chromatographic techniques were applied to isolate constituents. A combination of IR, ESI-MS, NMR and 2D-NMR spectroscopy was used to identify structures. RESULT: Four compounds were isolated from the ethyl acetate fraction of this plant, and the structure of them have identified as 2alpha, 3beta, 19beta-trihydroxyolean-12-ene-23,28-dioic acid (1), 2alpha, 3beta, 21beta-trihydroxyolean-12-ene-28-oic acid (2), 2alpha, 3beta, 23-trihydroxyurs-12-ene-28-oic acid (3) and stigmast-5 (6), 22 (23)-diene-3beta-ol (4). CONCLUSION: The NMR data of compound 1 was completely assigned by 2D-NMR techniques, including HMBC and HMQC. Compounds 1-4 were isolated for the first time from Gesneriaceae.

[Effects of stigma maydis polysaccharide on gastrointestinal movement].

OBJECTIVE: To study the effect of stigma maydis polysaccharide (SMPS) on gastrointestinal movement. METHOD: Taking charcoal as the indicator and taking ratio of charcoal movement, beginning time of black excretion and stool amount as the index to observe the effect of SMPS on intestinal movement in mice. Taking emthylorange as the indicator and taking the ratio of residual rate of methylorange as the index to observe the effect of SMPS on gastric emptying in mice. Taking methylene blue as the indicator and taking the time of gastric emptying and movement speed of intestinal content as the index to observe the effect of SMPS on gastrointestinal movement in rats. Observing the changes of cholecystokinin (CCK) level in plasm in rats. RESULT: Compared with control, the ratio of charcoal movement increased in mice (P <0.01). The beginning time of black excretion shortened and the stool amount increased in mice (P <0.01). The ratio of residual rate of methylorange increased in mice (P <0. 01). The time of gastric emptying prolonged in rats (P <0.01). The movement speed of intestinal content in rats accelerated (P <0.01). CCK level in plasm increased in rats (P < 0.05). CONCLUSION: Effects of stigma maydis polysaccharide on gastrointestinal movement are probably related to the increasing of CCK level in plasm.

[Study on extraction and drying of Ligusticum chuanxiong in Gan-ning Granule].

OBJECTIVE: To find out the optimum extract process for Ligusticum chuanxiong in Gan-ning Granule, and studyed the methods of concentration and dry for the extract. METHOD: With the yield of ferulic acid as the assessment index, to optimize the 80% alcohol totalling, extracting times and circumfluence time for extract process by the orthogonal design, to optimize the inlet-air temperature, feed speed and density of feed for spry drying by the orthogonal design. RESULT: The optimum procedure was the ferulic acid were extracted for 1 hour with 3 times of 80% alcohol. While extracting times effected it most porminently. The optimal processing conditions of spry drying were inlet-air temperature 120 degrees C, feed speed 8.5 mL x min(-1) and density of feed 1.15, While feed speed effected it most porminently. CONCLUSION: The experimental results provide the basis for the extraction process and drying process of the ferulic acid in ligusticum chuanxiong.

[Study on the chemical constituents of Mitragyna rotundifolia].

Twelve compounds were isolated from the EtOAc-soluble and ButOH-soluble portions of the EtOH extract from the bark of Mitragyna rotundifolia. These compounds were identified by their spectral data as dauricine (1), 3,4-dihydroxybezoic acid (2), beta-sitosterol (3), scopleton (4),3,4,5-trimethyoxyphenol-1-glucopyranoside (5), taraxerol (6), 4-hydroxy-3-methyloxybenzoic acid (7), 3-hydroxy-4-methyloxybenzoic acid (8), caffeic acid (9), gambirine (10), gambireine (11),1,1-dimetheyl-2-acetl-diethyl ether (12), respectively. All compounds were isolated from this genus for the first time.

Bcl-2 switches the type of demise from apoptosis to necrosis via cyclooxygenase-2 upregulation in HeLa cell induced by hydrogen peroxide.

Bcl-2 is best known for its anti-apoptotic function in a wide variety of cell types. The objective of this study was to investigate the effects of bcl-2 on the types of cell demise in the HeLa/bcl-2 cells induced by H2O2. The HeLa cell expressed stably bcl-2 was established and defined as the HeLa/bcl-2 cell strain, while the cell transfected with the empty expression vector was defined as the HeLa/vector cell strain. MTT assay revealed that the HeLa/bcl-2 cells showed a shorter life span. BrdU incorporation assay indicated that the bcl-2 exerted anti-demise effect on the HeLa/bcl-2 cells at the low concentration of H2O2. However, at the high concentration of H2O2, the death of the HeLa/bcl-2 cells was more than that of the HeLa/vector cells. The flow cytometry demonstrated that H2O2 mainly induced apoptosis in the HeLa/vector cells and elicited necrosis in the HeLa/bcl-2 cells. The addition of celecoxib to the cells treated by H2O2 could increase apoptosis in the HeLa/vector cells and convert necrosis into apoptosis in the HeLa/bcl-2 cells. The higher levels of cellular free radical and GSH were found in the HeLa/bcl-2 cells, but not in the HeLa/vector cells. With 200 microM H2O2 challenge for 48 h, the level of the cellular free radical was increased in the both strains, while the level of the GSH was decreased in the both strains. Celecoxib could reverse the difference between the both strains led by H2O2. Western blotting showed that the expression of COX-2 was always higher in the HeLa/bcl-2 cells than in the HeLa/vector cells under the both of treated and untreated with H2O2, while the level of COX-1 was relative stable in the both strains. These results suggested that the crosstalk between the bcl-2 and the COX-2 pathways could exist, the bcl-2 might up-regulate COX-2 to modify sensitivity to the types of demise in the HeLa/bcl-2 cell.

Thalidomide inhibits growth of tumors through COX-2 degradation independent of antiangiogenesis.

Thalidomide is an antiangiogenic drug and is clinically useful in a number of cancers. However, the molecular mechanism by which thalidomide exerts its antitumor effects is poorly understood. This study was designed to clarify the relationship between antiangiogenesis and antitumor effects of thalidomide and to explore the molecular mechanism for its antitumor activity. We evaluated the effects of thalidomide on the growth of human tumor cells expressing (MCF-7 and HL-60) or not expressing (HeLa and K562) COX-2 in vitro. We also studied the effects of thalidomide on COX-1, COX-2 or bcl-2 expression, TNFalpha, VEGF, GSH and cytochrome c in these cells. Thalidomide could inhibit tumor growth in a concentration-dependent manner in MCF-7 and HL-60; its IC50s for them were 18.36+/-2.34 and 22.14+/-2.15 microM, respectively, while this effect was not observed in HeLa and K562. Thalidomide reduced COX-2 expression accompanied by a decrease of bcl-2 protein, TNFalpha, VEGF, GSH and an increased cytochrome c, but had no effect on that of COX-1, in MCF-7 and HL-60. Moreover, cells not expressing COX-2 were insensitive to the growth-inhibitory and effects on cytokines of thalidomide. In our mouse xenograft model of OVCAR-3 and HCT-8, we found that thalidomide could decrease intratumoral microvessel density in both tumors; it exerted antitumor effects only on OVCAR-3 expressing COX-2 but did not on HCT-8 not expressing COX-2. Effect of thalidomide on COX-1 and COX-2 in vivo was consistent with that of in vitro. These results demonstrated that thalidomide might inhibit growth of tumors through COX-2 degradation independent of antiangiogenesis.

[Synthesis and antibacterial activity of 2-(3-pyridyl)-5-([(5-aryl-1,3,4-oxadiazol-2-yl) methylene]thio)-1,3,4-oxadiazoles].

AIM: Studies on synthesis and antibacterial activity of new heterocycles. METHODS: The cyclocondensation of [(3-pyridyl)-1,3,4-oxadiazol-2-yl] thio acetic acid with various aroyl hydrazines in the presence of POCl3 and xylene gave the corresponding titled compounds, and the in vitro antibacterial activity was primarily evaluated by the method of cupplate diffusion solution. RESULTS: Sixteen novel titled compounds were synthesized, their structures were confirmed by IR, 1HNMR, MS and elemental analysis. Biological screening results demonstrated that most of the compounds prepared displayed potential antibacterial activity. CONCLUSION: Oxadiazoles incorporting pyridyl oxadiazole ring may be usefully antibacterial candidate drugs.