Synthesis of modified homo-N-nucleosides from the reactions of mesityl nitrile oxide with 9-allylpurines and their influence on lipid peroxidation and thrombin inhibition

New Quinolylnitrones for Stroke Therapy: Antioxidant and Neuroprotective ( Z)- N- tert-Butyl-1-(2-chloro-6-methoxyquinolin-3-yl)methanimine Oxide as a New Lead-Compound for Ischemic Stroke Treatment

We describe herein the synthesis and neuroprotective capacity of an array of 31 compounds comprising quinolyloximes, quinolylhydrazones, quinolylimines, QNs, and related heterocyclic azolylnitrones. Neuronal cultures subjected to oxygen-glucose deprivation (OGD), as experimental model for ischemic conditions, were treated with our molecules at the onset of recovery period after OGD and showed that most of these QNs, but not the azo molecules, improved neuronal viability 24 h after recovery. Especially, QN ( Z)- N-tert-butyl-1-(2-chloro-6-methoxyquinolin-3-yl)methanimine oxide (23) was shown as a very potent neuroprotective agent. Antioxidant analysis based on the ability of QN 23 to trap different types of toxic radical oxygenated species supported and confirmed its strong neuroprotective capacity. Finally, QN 23 showed also neuroprotection induction in two in vivo models of cerebral ischemia, decreasing neuronal death and reducing infarct size, allowing us to conclude that QN 23 can be considered as new lead-compound for ischemic stroke treatment.

Structure-activity relationship studies for multitarget antithrombotic drugs

Thrombosis is a complex process involving multiple pathways. Currently, therapy relies on the combination of two or more antithrombotic drugs, showing that inhibiting more than one target provides benefits in the prevention and treatment of thrombosis. This review focuses on structure-activity relationship studies of molecules possessing multiple actions against thrombosis, namely, dual inhibitors of coagulation, dual inhibitors of coagulation and platelet aggregation, and also dual inhibitors of platelet aggregation. EP217609 has just entered clinical trials, which raise the expectations on the multitarget strategy to prevent or treat thrombosis.

Synthesis and biological evaluation of various new bis-isoxazoline derivatives as potential antioxidant additives

1,4-Bis[4-(4-benzoyl-5-phenylisoxazol-3-yl)-3-methyl-1-phenylpyrazol-5-yloxy]benzene and its derivatives were synthesised. The antioxidant activities of these compounds were investigated in vitro assay systems, such as lipid peroxidation, 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azino-bis(3-ethyl-1,3-benzothiazoline-6-sulfonic acid), superoxide, hydroxyl radicals scavenging and reducing power assay. The results show that the target compounds with nitro- and chloro-substituents at the 4-position of the benzene ring had more effective antioxidant power and better radical scavenging activity (RSA) (%) values when compared to those of butylated hydroxytoluene, trolox, caffeic acid and ascorbic acid, respectively..

In vitro inflammatory/anti-inflammatory effects of nitrate esters of purines

Six purine analogues bearing a nitrate ester group (potential NO donor) were tested on human THP-1 macrophages to investigate their effects on the inflammatory response. Only three analogues increased the basal level of IL-1β. Two analogues exacerbated the inflammatory response induced by ATP but not that induced by H2O2. Only 6-[4-(6-nitroxyacetyl)piperazin-1-yl]-9H-purine (compound MK128) abolished ATP or H2O2-induced IL-1β production in the culture medium. Similar results were reproduced on macrophages differentiated from buffy coats and stimulated with LPS. MK128 was the only analogue to release NO and leading to nitrite formation in the culture medium. The EC50 for inhibition of induced IL-1β production by the cells was estimated to be 10-12µg/ml (about 36µM) and corresponded to the production of around 30µM nitrites in the culture medium. This anti-inflammatory effect of MK128 was mimicked by trinitrin used in 10 fold higher concentrations. Preincubation of cells with NO trapper cPTIO partially abolished the beneficial effect of MK128 while MK137, a ONO2 deprived analogue of MK128, was not able to inhibit induced IL-1β production and proved to be inflammatory. Moreover, purinergic channel inhibitors (oATP and U73122) inhibited the MK137 inflammatory effect. Finally, MK128 reduced the quantity of p20 caspase-1 produced in the culture medium. We suggest that MK128 inhibits IL-1β production via NO production and subsequent inflammasome component nitrosylation. On the opposite MK137, deprived from ONO2 group, could act as agonist of purinergic receptors and could thus activate inflammasome.

Α-aryl-N-alkyl nitrones, as potential agents for stroke treatment: synthesis, theoretical calculations, antioxidant, anti-inflammatory, neuroprotective, and brain-blood barrier permeability properties

We report the synthesis, theoretical calculations, the antioxidant, anti-inflammatory, and neuroprotective properties, and the ability to cross the blood-brain barrier (BBB) of (Z)-α-aryl and heteroaryl-N-alkyl nitrones as potential agents for stroke treatment. The majority of nitrones compete with DMSO for hydroxyl radicals, and most of them are potent lipoxygenase inhibitors. Cell viability-related (MTT assay) studies clearly showed that nitrones 1-3 and 10 give rise to significant neuroprotection. When compounds 1-11 were tested for necrotic cell death (LDH release test) nitrones 1-3, 6, 7, and 9 proved to be neuroprotective agents. In vitro evaluation of the BBB penetration of selected nitrones 1, 2, 10, and 11 using the PAMPA-BBB assay showed that all of them cross the BBB. Permeable quinoline nitrones 2 and 3 show potent combined antioxidant and neuroprotective properties and, therefore, can be considered as new lead compounds for further development in specific tests for potential stroke treatment.