Mechanistic insights into the selectivity of bicyclophosphorothionate antagonists for housefly versus rat GABA receptors.

Background: γ-Aminobutyric acid (GABA) receptors (GABARs) are validated targets of insecticides. Bicyclophosphorothionates are a group of insecticidal compounds that act as noncompetitive antagonists of GABARs. We previously reported that the analogs exhibit various degrees of selectivity for housefly versus rat GABARs, depending on substitutions at the 3- and 4-positions.

Inhibitory effects of salidroside on MCF-7 breast cancer cells .

Objective: We investigated the antitumor effects of salidroside and preliminarily examined its underlying mechanisms by establishing a nude mouse model bearing MCF-7 breast cancer cell xenografts.

Methods: The mice were grouped and intraperitoneally injected with salidroside, paclitaxel, or physiological saline. Tumor samples were weighed, and immunohistochemical staining with hematoxylin and eosin and anti-CD34 antibody was performed.

Advances in Research on Anticancer Properties of Salidroside.

Salidroside is a phenolic secondary metabolite present in plants of the genus Rhodiola, and studies investigating its extensive pharmacological activities and mechanisms have recently attracted increasing attention. This review summarizes the progress of recent research on the antiproliferative activities of salidroside and its effects on breast, ovarian, cervical, colorectal, lung, liver, gastric, bladder, renal, and skin cancer as well as gliomas and fibrosarcomas. Thus, it provides a reference for the further development and utilization of salidroside.

Advances in diarylpyrimidines and related analogues as HIV-1 nonnucleoside reverse transcriptase inhibitors.

HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) have been playing an important role in the fight against acquired immunodeficiency syndrome (AIDS). Diarylpyrimidines (DAPYs) as the second generation NNRTIs, represented by etravirine (TMC125) and rilpivirine (TMC278), have attracted extensive attention due to their extraordinary potency, high specificity and low toxicity. However, the rapid emergence of drug-resistant virus strains and dissatisfactory pharmacokinetics of DAPYs present new challenges.

Investigation of serum amino acids involved in gallic acid detoxification of formaldehyde by liquid chromatography/tandem mass spectrometry and neutral loss scan.

Rationale: Gallic acid is one of the most common polyphenols in natural products and human diet. The consumption of gallic acid reduces the incidence of cardiovascular diseases, chronic metabolic disorders and cancers. Most previous publications focused on the antioxidative or prooxidative properties of gallic acid.

Design and synthesis of hybrids of diarylpyrimidines and diketo acids as HIV-1 inhibitors.

Based on the strategy of molecular hybridization, diketo acid fragment as a classical phamacophore of integrase inhibitors was introduced to reverse transcriptase inhibitors diarylpyrimidines to design a series of diarylpyrimidine-diketo acid hybrids (DAPY-DKAs). The target molecules 10b and 11b showed inhibitory activities against WT HIV-1 with EC values of 0.18μM and 0.

Structural modifications of diarylpyrimidines (DAPYs) as HIV-1 NNRTIs: Synthesis, anti-HIV activities and SAR.

30 new analogues of diarylpyrimidines were synthesized for further structural modifications, involving not only the linker but also the wing α of DAPYs. The anti-HIV-1 activities of all target molecules were evaluated, and most of them exhibited potent anti-HIV-1 (WT) activities and low cytotoxicities. Among which, compound 4g showed excellent activities against WT HIV-1 with an EC value of 5.

Advances in rationally designed dual inhibitors of HIV-1 reverse transcriptase and integrase.

Reverse transcriptase (RT) and integrase (IN) are two indispensable enzymes in human immunodeficiency virus type 1 (HIV-1) replication. RT is responsible for the transformation of the single-stranded RNA viral genome into double-stranded DNA, and IN catalyzes the integration of viral DNA into the host DNA. Although highly active antiretroviral therapy (HAART) combining nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs/NtRTIs) with nonnucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs) could suppress successfully HIV viral load and reduce evidently the mortality of HIV infected people, it involves the difficulty of perfect adherence, and other drawbacks such as viral rebound, toxicities and multi-drug resistances.

A novel family of diarylpyrimidines (DAPYs) featuring a diatomic linker: Design, synthesis and anti-HIV activities.

To improve the conformational flexibility and positional adaptability of the traditional diarylpyrimidines (DAPYs), a family of diarylpyrimidines featuring a C-N diatomic linker between the left wing benzene ring and the central pyrimidine was firstly designed, synthesized, and evaluated for in vitro anti-HIV activity. Most of target molecules showed excellent activities against wild-type (WT) HIV-1. Among them the most potent two compounds 12h and 12r displayed extremely potent WT HIV-1 inhibitory activities with an EC50 of 2.

Electrophysiological evidence for 4-isobutyl-3-isopropylbicyclophosphorothionate as a selective blocker of insect GABA-gated chloride channels.

Invertebrate γ-aminobutyric acid (GABA)-gated chloride channels (GABACls) and glutamate-gated chloride channels (GluCls), which function as inhibitory neurotransmitter receptors, are important targets of insecticides and antiparasitic agents. The antagonism of GABACls and GluCls by 4-isobutyl-3-isopropylbicyclophosphorothionate (PS-14) was examined in cultured cockroach and rat neurons using a whole-cell patch-clamp method. The results indicated that PS-14 selectively blocks cockroach GABACls relative to cockroach GluCls and rat GABACls.

Synthesis and structure-activity relationship analysis of bicyclophosphorothionate blockers with selectivity for housefly gamma-aminobutyric acid receptor channels.

Background: Bicyclophosphorothionates (2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane-1-sulfides) are blockers (or non-competitive antagonists) of gamma-aminobutyric acid (GABA) receptor channels.

Homology modeling and atomic level binding study of GABA(A) receptor with novel enaminone amides.

A series of novel enaminone amides with improved side effect were synthesized by Hogenkamp et al. To explore the action mechanisms of enaminone amides, the homology model of rat alpha1beta2gamma2 GABAR was generated using the cryo-electron microscopy structure of the nAChR of Torpedo marmorata and the AChBP of Lymnaea stagnalis as the templates. Molecular docking and pharmacophore analyses allowed us to speculate the critical residues involving to the recognition of the ligands.

CoMFA and molecular docking studies of benzoxazoles and benzothiazoles as CYP450 1A1 inhibitors.

For better understanding of the molecular interactions of inhibitors with CYP450 1A1, a series of benzoxazoles and benzothiazoles were analyzed by comparative molecular field analysis (CoMFA) and molecular docking. Two conformer-based alignment strategies were employed to construct reliable CoMFA models. The best CoMFA model yielded a predictive correlation coefficient r(2)(pred) value of 0.

3D-QSAR studies of insecticidal anthranilic diamides as ryanodine receptor activators using CoMFA, CoMSIA and DISCOtech.

To explore the three-dimensional quantitative structure-activity relationships (3D-QSAR) and the pharmacophore model of a new class of potent activators of the anthranilic diamide ryanodine receptor (RyR), comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and distance comparison technique (DISCOtech) were performed on 38 anthranilic diamides. Successful CoMFA and CoMSIA models yielded "leave-one-out" (LOO) cross-validated correlation coefficient (q(2)) values of 0.785 and 0.

Selectivity of Imidacloprid for fruit fly versus rat nicotinic acetylcholine receptors by molecular modeling.

For better understanding of the mechanisms of selective binding of the representative nicotinic acetylcholine receptor (nAChR) agonist neonicotinoid Imidacloprid (IMI), three-dimensional models of fruit fly alpha 1 beta 2 and rat alpha 4beta 2 nAChRs were generated by homology modeling, using the crystal structure of the acetylcholine-binding protein (AChBP) of Lymnaea stagnalis and the nAChR of mus musculus as the templates, respectively. The conformational stability of the two models was studied by molecular dynamics (MD) and the quality of the models was confirmed. Especially, insecticide Imidacloprid was docked into the putative binding site of the fruit fly alpha 1 beta 2 and rat alpha 4 beta 2 nAChRs by Surflex-docking.

Homology modeling of human alpha 1 beta 2 gamma 2 and house fly beta 3 GABA receptor channels and Surflex-docking of fipronil.

To further explore the mechanism of selective binding of the representative gamma-aminobutyric acid receptors (GABARs) noncompetitive antagonist (NCA) fipronil to insect over mammalian GABARs, three-dimensional models of human alpha 1 beta 2 gamma 2 and house fly beta 3 GABAR were generated by homology modeling, using the cryo-electron microscopy structure of the nicotinic acetylcholine receptor (nAChR) of Torpedo marmorata as a template. Fipronil was docked into the putative binding site of the human alpha 1 beta 2 gamma 2 and house fly beta 3 receptors by Surflex-docking, and the calculated docking energies are in agreement with experimental results. The GABA receptor antagonist fipronil exhibited higher potency with house fly beta 3 GABAR than with human alpha 1 beta 2 gamma 2 GABAR.

Investigation of structural requirements for inhibitory activity at the rat and housefly picrotoxinin binding sites in ionotropic GABA receptors using DISCOtech and CoMFA.

A number of widely diverse compounds that show inhibitory activities at the picrotoxinin binding sites in housefly and rat GABA receptors were investigated by using the distance comparison technique (DISCOtech) and comparative molecular field analysis (CoMFA) methods to explore the pharmacophore models and the three-dimensional quantitative structure-activity relationships (3D-QSAR) of the compounds. These compounds consist of three diverse types of noncompetitive GABA receptor antagonists, i.e.

[The optimum condition on baicalin extraction from Scutellaria baicalensis].

Objective: To optimize the extraction process of baicalin from Scutellaria Baicalensis Georgi with ethanol.

Methods: The extraction process of baicalin from Scutellaria Baicalensis Georgi was optimized with the aid of orthogonal experiments.

Results: The optimal parameters were obtained as follows: extracting temperature, extracting time, ethanol concentration and mechanical stirring speed were 80 degrees C, 1 h, 60% and 400 r/min, respectively.

Expression of a wheat cytochrome P450 monooxygenase in yeast and its inhibition by glyphosate.

Glyphosate is a non-selective herbicide which acts by inhibiting 5-enolpyruvylshikimate-3-phosphate synthase. Wheat cytochrome P450 monooxygenase specifically catalyzes the metabolism of some sulfonylurea herbicides such as chlorsulfuron and triasulfuron. Here we report that glyphosate is an inhibitor of a wheat cytochrome (CYP71C6v1), the cDNA of which was amplified by RT-PCR and heterologously expressed in yeast.