Design, synthesis, and biological evaluation of lipophilically modified bisphenol Z derivatives.

In the present study, a small library of bisphenol Z (BPZ) derivatives was synthesized and investigated for anti-proliferative effects in cultured breast and glioblastoma cell lines. Synthesized BPZ derivatives varied in molecular size, polarity, and lipophilicity. Of the 8 derivatives tested, compounds 4 and 6, both of which displayed the highest degree of lipophilicity, were most active at inducing cell death as determined by the XTT assay. Cell membranes were interrogated using trypan blue staining and were shown to remain intact during treatments with 4 and 6. Activation of caspase enzymes (3 and/or 7) was noted to occur following treatment with compound 4. Polar BPZ derivatives, those with a substituted amine or alcohol, were devoid of any inhibitory or proliferative effects. The remaining derivatives seem to lack sufficient lipophilicity to execute an overt toxic effect. Our results suggest that increasing the lipophilic character of BPZ enhances the cytotoxic effects.

New diphenylmethane derivatives as peroxisome proliferator-activated receptor alpha/gamma dual agonists endowed with anti-proliferative effects and mitochondrial activity.

We screened a short series of new chiral diphenylmethane derivatives and identified potent dual PPARα/γ partial agonists. As both enantiomers of the most active compound 1 displayed an unexpected similar transactivation activity, we performed docking experiments to provide a molecular understanding of their similar partial agonism. We also evaluated the ability of both enantiomers of 1 and racemic 2 to inhibit colorectal cancer cells proliferation: (S)-1 displayed a more robust activity due, at least in part, to a partial inhibition of the Wnt/ß-catenin signalling pathway that is upregulated in the majority of colorectal cancers. Finally, we investigated the effects of (R)-1, (S)-1 and (R,S)-2 on mitochondrial function and demonstrated that they activate the carnitine shuttle system through upregulation of carnitine/acylcarnitine carrier (CAC) and carnitine-palmitoyl-transferase 1 (CPT1) genes. Consistent with the notion that these are PPARα target genes, we tested and found that PPARα itself is regulated by a positive loop. Moreover, these compounds induced a significant mitochondrial biogenesis. In conclusion, we identified a new series of dual PPARα/γ agonists endowed with novel anti-proliferative properties associated with a strong activation of mitochondrial functions and biogenesis, a potential therapeutic target of the treatment of insulin resistance.

Structure-activity relationships of bisphenol A analogs at estrogen receptors (ERs): discovery of an ERα-selective antagonist.

Our multi-template approach for drug discovery, focusing on protein targets with similar fold structures, has yielded lead compounds for various targets. We have also shown that a diphenylmethane skeleton can serve as a surrogate for a steroid skeleton. Here, on the basis of those ideas, we hypothesized that the diphenylmethane derivative bisphenol A (BPA) would bind to the ligand-binding domain of estrogen receptors (ERs) in a similar manner to estradiol and act as a steroid surrogate. To test this idea, we synthesized a series of BPA analogs and evaluated their structure-activity relationships, focusing on agonistic/antagonistic activities at ERs and ERα/ERß subtype selectivity. Among the compounds examined, 18 was found to be a potent ERα-antagonist with high selectivity over ERß and androgen receptor under our assay conditions. A computational docking study suggested that 18 would bind to the antagonistic conformation of ERα. ERα-selective antagonists, such as 18, are candidate agents for treatment of breast cancer.

Discovery of novel tricyclic compounds as squalene synthase inhibitors.

In the present article, we have reported the design, synthesis, and identification of highly potent benzhydrol derivatives as squalene synthase inhibitors (compound 1). Unfortunately, the in vivo efficacies of the compounds were not enough for acquiring the clinical candidate. We continued our investigation to obtain a more in vivo efficacious template than the benzhydrol template. In our effort, we focused on a benzoxazepine ring and designed a new tricyclic scaffold by the incorporation of heterocycle into it. Prepared pyrrolobenzoxazepine derivatives showed further efficient in vitro and in vivo activities.

Discovery of atrop fixed alkoxy-aminobenzhydrol derivatives: novel, highly potent and orally efficacious squalene synthase inhibitors.

We have recently reported the discovery of the new benzhydrol template, which has a highly potent inhibitory activity for squalene synthase, as typified by compound 1 (SSI IC(50)=0.85 nM). However, it was composed of a pair of easy rotatable atropisomers. In the effort to fix the isomerization, a highly potent alkoxy-aminobenzhydrol scaffold was developed. Some of these acquired compounds demonstrating strong cholesterol synthesis inhibitory activities in a rat hepatic cell. Moreover, two of the series compounds exhibited specific plasma lipid-lowering effects in in vivo animal models.

Development of 2-substituted-N-(naphth-1-ylmethyl) and N-benzhydrylpyrimidin-4-amines as dual cholinesterase and Aß-aggregation inhibitors: Synthesis and biological evaluation.

A group of 2-substituted N-(naphth-1-ylmethyl)pyrimidin-4-amines (6a-k) and N-benzhydrylpyrimidin-4-amines (7a-k) in conjunction with varying steric and electronic properties at the C-2 position were designed, synthesized and evaluated as dual cholinesterase and amyloid-ß (Aß)-aggregation inhibitors. The naphth-1-ylmethyl compound 6f (2-(4-cyclohexylpiperazin-1-yl)-N-(naphth-1-ylmethyl)pyrimidin-4-amine) exhibited optimum dual ChE (AChE IC(50)=8.0 µM, BuChE IC(50)=3.9 µM) and hAChE-promoted Aß-aggregation inhibition (30.8% at 100 µM), whereas in the N-benzhydryl series, compound 7f (N-benzhydryl-2-(4-cyclohexylpiperazin-1-yl)pyrimidin-4-amine) exhibited optimum combination of dual ChE (AChE IC(50)=10.0 µM, BuChE IC(50)=7.6µM) and hAChE-promoted Aß-aggregation inhibition (32% at 100 µM). These results demonstrate that a 2,4-disubstituted pyrimidine ring serves as a suitable template to target multiple pathological routes in AD, with a C-2 cyclohexylpiperazine substituent providing dual ChE inhibition and potency whereas a C-4 diphenylmethane substituent provides Aß-aggregation inhibition.

Discovery of a new 2-aminobenzhydrol template for highly potent squalene synthase inhibitors.

To obtain small and efficient squalene synthase inhibitors, a flexible 2-aminobenzhydrol open form structure was designed and showed potent inhibitory activity comparable to 4,1-benzoxazepin compounds. Further chemical modification led to the discovery of a novel template with a strong squalene synthase inhibitory activity, and its basic structure-activity relationship was revealed. The X-ray crystallographic data of compound 12 bound to the active site of squalene synthase provided an important insight into the binding mode of this alternative template that formed 11-membered ring conformations with an intramolecular hydrogen bond.

Characterisation of hydrazides and hydrazine derivatives as novel aspartic protease inhibitors.

Virtual screening of an in-house virtual library of synthetic compounds using FlexX, followed by enzyme inhibition, identified hydrazide and hydrazine derivatives as novel aspartic protease inhibitors. These compounds inhibited human cathepsin D and Plasmodium falciparum plasmepsin-II with low micromolar concentrations (IC(50) = 1-2.5 microM). Modelling studies with plasmepsin-II predicted binding of ligands at the centre of the extended substrate-binding cleft, where hydrazide/hydrazine parts of the inhibitors acted as the transition state mimic by forming electrostatic interactions with catalytic aspartates.

Synthesis and evaluation of (S,S)-N,N'-bis-[3-(2,2',6,6'-tetramethylbenzhydryloxy)-2-hydroxy-propyl]-ethylenediamine (S2824) analogs with anti-tuberculosis activity.

In order to identify new and potent candidate drugs to treat tuberculosis, a library of compounds was screened, and (S,S)-N,N'-bis-[3-(2,2',6,6'-tetramethylbenzhydryloxy)-2-hydroxy-propyl]-ethylenediamine (S2824) was identified as a hit in the screen. This research discusses our efforts to synthesize and test 30 analogs of this hit for activity against Mycobacterium tuberculosis. Two compounds with homopiperazine ring possess high in vitro activity against drug sensitive and resistant M. tuberculosis with MICs 0.78-3.13 microg/mL (or 1.22-4.88 microM).

Discovery of diphenylmethane analogs as anti-bovine diarrhea viral agents.

Based on antiviral screening of our diphenylmethane derivatives prepared as steroid substitutes, we identified a 1,1-diphenylcyclobutane analog (9) and two diethyldiphenylsilane analogs (12 and 13) as superior lead compounds with potent anti-bovine viral diarrhea virus (BVDV) activity, having 50% effective concentration (EC(50): based on reduction of BVDV replication-induced cell destruction) and 50% cytotoxic concentration (CC(50): based on reduction of viable cell number) values of 6.2-8.4 microM and >100 microM, respectively, in Madin-Darby bovine kidney (MDBK) cells infected with BVDV.

Synthesis, activity and toxicity of novel macrocyclic ligands against HIV-1 in Jurkat and CEM-SS cell lines.

We have developed versatile synthetic routes that afford metal-free macrocycles containing different functionalities in their framework. Novel oxaziridine and amide containing macrocycles were synthesized, and the metal complexes of the latter were also prepared. A series of theophilline and thymidine side-arm containing podands as well as macrocycles were obtained employing the same methodology. The primary anti-viral tests of these synthetic compounds for anti-HIV-1 activity was carried out using the XTT-based cytopathicity assay (CEM-SS cells) with AZT as positive control. It was found that the nature of the macrocyclic headgroups affected the anti-HIV-1 activity. Heteroatom containing macrocyclic headgroups displayed activity in the micromolar range. Metal complexation did not enhance the activity and side-arm substitution resulted in inactive compounds. Cell viability determined in both Jurkat and CEM-SS cells was strongly dependent on the structure of the macrocyclic framework. The oxaziridine moieties in the macrocycle were highly toxic to CEM-SS and less toxic to Jurkat cell lines, while amide containing macrocycles were toxic to neither.

Screening of natural and synthetic drugs against Trypanosoma cruzi. 1. Establishing a structure/activity relationship.

The activity of 45 compounds against bloodstream forms of Trypanosoma cruzi was investigated. The aim was to consider new agents which might subsequently be assayed for chemoprophylaxis in donated blood. In a preliminary screening the drugs were assayed (50 to 1,000 microM at 29 degrees C) and those active against bloodstream forms at concentrations below 600 microM were selected for further assays under blood-bank conditions (4 degrees C/24 h). Three compounds isolated from natural sources and six synthetic agents were selected. The active compounds of plant origin included purpurin, a member of the trihydroxylated anthraquinone group, which is known to exhibit trypanocidal activity. Among the active synthetic compounds, five displayed a common structural feature in that they were potentially one-electron acceptors, via reductive functional groups. All five compounds form tricentered C or N intermediates, joined in a hypothetical 'Y' radical pattern. It is possible that the trypanocidal mechanisms initiated by these compounds are similar to those found with crystal violet, since this dye, which is already used in endemic areas for the treatment of banked blood, also conforms to this general Y structural pattern.