Synthesis and evaluation of β-hydroxytriazoles and related compounds as antitubercular agents

A new series of β-hydroxytriazoles were synthesized and evaluated as Mycobacterium tuberculosis inhibitors. Our strategy implied the synthesis of alkyne precursors through a Barbier reaction between benzaldehydes and propargyl bromide followed by click chemistry to afford substituted β-hydroxyl benzyltriazoles. These compounds are also key intermediates either for oxidation reactions leading to α,β-diketotriazoles or for elimination reactions affording styryl triazoles. Evaluation of all new compounds for in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv resulted in compounds with MIC up to 7 μM.

Distinct CCK-2 receptor conformations associated with β-arrestin-2 recruitment or phospholipase-C activation revealed by a biased antagonist

Seven-transmembrane receptors (7TMRs), also termed G protein-coupled receptors (GPCRs), form the largest class of cell surface membrane receptors, involving several hundred members in the human genome. Nearly 30% of marketed pharmacological agents target 7TMRs. 7TMRs adopt multiple conformations upon agonist binding. Biased agonists, in contrast to non-biased agonists, are believed to stabilize conformations preferentially activating either G-protein- or β-arrestin-dependent signaling pathways. However, proof that cognate conformations of receptors display structural differences within their binding site where biased agonism initiates, are still lacking. Here, we show that a non-biased agonist, cholecystokinin (CCK) induces conformational states of the CCK2R activating Gq-protein-dependent pathway (CCK2R(G)) or recruiting β-arrestin2 (CCK2R(β)) that are pharmacologically and structurally distinct. Two structurally unrelated antagonists competitively inhibited both pathways. A third ligand (GV150013X) acted as a high affinity competitive antagonist on CCK2R(G) but was nearly inefficient as inhibitor of CCK2R(β). Several structural elements on both GV150013X and in CCK2R binding cavity, which hinder binding of GV150013X only to the CCK2R(β) were identified. At last, proximity between two conserved amino acids from transmembrane helices 3 and 7 interacting through sulfur-aromatic interaction was shown to be crucial for selective stabilization of the CCK2R(β) state. These data establish structural evidence for distinct conformations of a 7TMR associated with β-arrestin-2 recruitment or G-protein coupling and validate relevance of the design of biased ligands able to selectively target each functional conformation of 7TMRs.

In vitro toxicological effects of estrogenic mycotoxins on human placental cells: structure activity relationships

Zearalenone (ZEN) is a non-steroid estrogen mycotoxin produced by numerous strains of Fusarium which commonly contaminate cereals. After oral administration, ZEN is reduced via intestinal and hepatic metabolism to α- and β-zearalenol (αZEL and βZEL). These reduced metabolites possess estrogenic properties, αZEL showing the highest affinity for ERs. ZEN and reduced metabolites cause hormonal effects in animals, such as abnormalities in the development of the reproductive tract and mammary gland in female offspring, suggesting a fetal exposure to these contaminants. In our previous work, we have suggested the potential impact of ZEN on placental cells considering this organ as a potential target of xenobiotics. In this work, we first compared the in vitro effects of αZEL and βΖΕL on cell differentiation to their parental molecule on human trophoblast (BeWo cells). Secondly, we investigated their molecular mechanisms of action by investigating the expression of main differentiation biomarkers and the implication of nuclear receptor by docking prediction. Conversely to ZEN, reduced metabolites did not induce trophoblast differentiation. They also induced significant changes in ABC transporter expression by potential interaction with nuclear receptors (LXR, PXR, PR) that could modify the transport function of placental cells. Finally, the mechanism of ZEN differentiation induction seemed not to involve nuclear receptor commonly involved in the differentiation process (PPARγ). Our results demonstrated that in spite of structure similarities between ZEN, αZEL and βZEL, toxicological effects and toxicity mechanisms were significantly different for the three molecules.

Cinnamic acid derivatives as anticancer agents-a review

Cinnamic acid and its phenolic analogues are natural substances. Chemically, in cinnamic acids the 3-phenyl acrylic acid functionality offers three main reactive sites; substitution at the phenyl ring, addition at the α,β- unsaturation and the reactions of the carboxylic acid functionality. Owing to these chemical aspects cinnamic acid derivatives received much attention in medicinal research as traditional as well as recent synthetic antitumor agents. We observed that in spite of their rich medicinal tradition, cinnamic acid derivatives and their anticancer potentials remained underutilized for several decades since the first published clinical use in 1905. In last two decades, there has been huge attention towards various cinnamoyl derivatives and their antitumor efficacy. This review provides a comprehensive and unprecedented literature compilation concerning the synthesis and biological evaluation of various cinnamoyl acids, esters, amides, hydrazides and related derivatives in anticancer research. We envisage that our effort in this review contributes a much needed and timely addition to the literature of medicinal research.

Antiatherogenic effect of bisvanillyl-hydralazone, a new hydralazine derivative with antioxidant, carbonyl scavenger, and antiapoptotic properties

Reactive oxygen species (ROS) generated within the vascular wall trigger low-density lipoprotein (LDL) oxidation, lipid peroxidation, and carbonyl stress that are involved in atherogenesis. We recently reported that the antihypertensive drug, hydralazine, exhibits carbonyl scavenger and antiatherogenic properties, but only moderate antioxidant activity, so that high concentrations are required for inhibiting LDL oxidation. We aimed to develop agents sharing both antioxidant and carbonyl scavenger properties. We have synthesized a new hydralazine derivative, the bisvanillyl-hydralazone (BVH). BVH strongly inhibited LDL oxidation induced by copper and by human endothelial cells (HMEC-1), and prevented the formation of macrophagic foam cells. BVH reduced both the extracellular generation of ROS (superoxide anion and hydrogen peroxide) induced by oxidized LDL (oxLDL), as well as intracellular oxidative stress and proteasome activation, NFkappaB activation, and oxLDL-mediated proinflammatory signaling. In parallel, BVH prevented the carbonyl stress induced by oxLDL on cellular proteins, and blocked the apoptotic cascade as assessed by the inhibition of Bid cleavage, cytochrome C release, and DEVDase activation. Lastly, BVH prevented atherogenesis and carbonyl stress in apoE(-/-) mice. In conclusion, BVH is the prototype of a new class of antioxidant and carbonyl scavenger agents designed for new therapeutical approaches in atherosclerosis.