Mechanistic studies for tri-targeted inhibition of enzymes involved in cholesterol biosynthesis by green tea polyphenols.

In the present study, we found that three enzymes, MVK, MDD and FPPS, in the mevalonate pathway (MVP) of cholesterol biosynthesis, can be simultaneously inhibited by two green tea polyphenols ((-)-epicatechin-3-gallate, ECG; (-)-epigallocatechin-3-gallate, EGCG). Molecular dynamics simulations and pharmacophore studies were carried out to elucidate the tri-targeted inhibition mechanisms. Our results indicate that similar triangular binding pockets exist in all three enzymes, which is essential for their binding with polyphenols. Two distinct binding poses for ECG and EGCG were observed in our MD simulations. These results shed light on the potential for further selective and multi-targeted inhibitor design for the treatment of hyperlipidemia.

Enhancing molecular shape comparison by weighted Gaussian functions.

Shape comparing technologies based on Gaussian functions have been widely used in virtual screening of drug discovery. For efficiency, most of them adopt the First Order Gaussian Approximation (FOGA), in which the shape density of a molecule is represented as a simple sum of all individual atomic shape densities. In the current work, the effectiveness and error in shape similarity calculated by such an approximation are carefully analyzed. A new approach, which is called the Weighted Gaussian Algorithm (WEGA), is proposed to improve the accuracy of the first order approximation. The new approach significantly improves the accuracy of molecular volumes and reduces the error of shape similarity calculations by 37% using the hard-sphere model as the reference. The new algorithm also keeps the simplicity and efficiency of the FOGA. A program based on the new method has been implemented for molecular overlay and shape-based virtual screening. With improved accuracy for shape similarity scores, the new algorithm also improves virtual screening results, particularly when a shape-feature combo scoring function is used.

Salvianolic acid A, a polyphenolic derivative from Salvia miltiorrhiza bunge, as a multifunctional agent for the treatment of Alzheimer's disease.

The effects of Salvianolic acid A (Sal A) on the treatment of Alzheimer's disease (AD) were investigated. Sal A significantly inhibits amyloid beta [Formula: see text] self-aggregation and disaggregates pre-formed [Formula: see text] fibrils, reduces metal-induced [Formula: see text] aggregation through chelating metal ions, and blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells. Sal A protects cells against [Formula: see text]-induced toxicity. Furthermore, Sal A, possibly because of the effects of decreasing toxicity effects of [Formula: see text] species, alleviates [Formula: see text]-induced paralysis in transgenic Caenorhabditis elegans. Circular dichroism (CD) experiments and Molecular dynamic (MD) simulations demonstrate that Sal A inhibits [Formula: see text] self-aggregation through binding to the C-terminus of [Formula: see text], and therefore stabilizing the [Formula: see text]-helical conformations. Altogether, our data show that Sal A, as the multifunctional agent, is likely to be promising therapeutics for AD.

On the value of homology models for virtual screening: discovering hCXCR3 antagonists by pharmacophore-based and structure-based approaches.

Human chemokine receptor CXCR3 (hCXCR3) antagonists have potential therapeutic applications as antivirus, antitumor, and anti-inflammatory agents. A novel virtual screening protocol, which combines pharmacophore-based and structure-based approaches, was proposed. A three-dimensional QSAR pharmacophore model and a structure-based docking model were built to virtually screen for hCXCR3 antagonists. The hCXCR3 antagonist binding site was constructed by homology modeling and molecular dynamics (MD) simulation. By combining the structure-based and ligand-based screenings results, 95% of the compounds satisfied either pharmacophore or docking score criteria and would be chosen as hits if the union of the two searches was taken. The false negative rates were 15% for the pharmacophore model, 14% for the homology model, and 5% for the combined model. Therefore, the consistency of the pharmacophore model and the structural binding model is 219/273 = 80%. The hit rate for the virtual screening protocol is 273/286 = 95%. This work demonstrated that the quality of both the pharmacophore model and homology model can be measured by the consistency of the two models, and the false negatives in virtual screening can be reduced by combining two virtual screening approaches.

Effect of electroacupuncture on expression of IFN-gamma-like immunoreactive substance in spinal cord of the rat / 中国针灸

<p><b>OBJECTIVE</b>To observe effect of electroacupuncture at "Zusanli" (ST 36) on expression of interferon-gamma (IFN-gamma)-like immunoreactive substance in spinal cord of the rat and to probe the mechanism.</p><p><b>METHODS</b>The IFN-gamma-like immunoreactive positive cell number in spinal cord of the rat was investigated with immunohistochemical SP method and microscopy.</p><p><b>RESULTS</b>After electroacupuncture at "Zusanli" (ST 36), IFN-gamma-like immunoreactive positive cell number in the spinal cord of the rat with electroacupuncture plus immunosuppression did not significantly change (P > 0.05). The number of positive cells in the dorsal horn in the rats with immunosuppression was significantly less than that in the normal control group (P < 0.05) with no significant change in other parts and with no significant difference between the electroacupuncture group and the control group (P > 0.05).</p><p><b>CONCLUSION</b>Electroacupuncture at "Zusanli" (ST 36) can increase expression of IFN-gamma-like immunoreactive substance in spinal cord of the rat, and acupuncture activates the nerve-immunoregulative network possibly by IFN-gamma as medium.</p>