Medicinal Chemistry - Volume 6, Issue 1, 2010

A novel acetylcholinesterase (AChE) reactivator, a bispyridinium aldoxime named K048, was first synthesized in 2003. It is a promising antidote against tabun poisoning. Afterwards, other studies on several cholinesterases (ChE) of different species (humans, rats, etc.) and models (in vitro or in vivo) were conducted. We tested this oxime against nine different AChE inhibitors using in vitro tests on rat brain homogenate as source of enzyme. Our results showed that oxime K048 reached promising reactivation activity in case of all tested AChE inhibitors, except cyclosarin, at oxime concentration 10-3 M. At a concentration of 10-5 M, which is more common for human use, only methylchlorpyrifos-inhibited AChE was reactivated.

A series of chrysin derivatives were prepared from 2-hydroxyacetophenone, 2,4-dihydroxyacetophenone, 2,4,6- trihydroxy- acetophenone, using modified Baker-Venkataraman transformation. Their anticancer activities in vitro were evaluated by the standard MTT method. The results of biological test showed that some of chrysin derivatives showed stronger anticancer activity than 5-fluorouracil.

Strong chelating ligands as oxodiacetate (oda) are model systems to study the process of metal trapping by living organisms. Vanadium compounds display interesting biological and pharmacological actions. In vertebrates, vanadium is stored mainly in bones. In the present study we report the effects of the complex of oda with vanadyl(IV) cation, VO(oda), on two osteoblast cell lines, one normal (MC3T3-E1) and the other tumoral (UMR106). VO(oda) exerted cytotoxic actions in osteoblasts as it was determined through a dose-dependent decrease in cell proliferation, and morphological and actin alterations. The putative mechanisms underlying VO(oda) deleterious effects were also investigated. The complex increased the level of ROS which correlated with a decreased in GSH/GSSG ratio. Besides, VO(oda) induced a dissipation of the mitochondria membrane potential (MMP) and promoted an increase in ERK cascade phosphorylation, which is involved in the regulation of cellular death and survival. All the effects were more pronounced in MC3T3-E1 than in UMR106 cells. ERK activation was inhibited by PD98059, Wortmanin and the ROS scavenger NAC (N-acetyl cysteine). These results suggest that VO(oda) stimulated ERKs phosphorylation by induction of free radicals involving kinases upstream of ERK pathway. The inhibitory effect of the complex on cell proliferation was partially reversed in both cell lines by NAC. Moreover, PD98059 and Wortmanin also partially reversed the inhibition of cell proliferation in the tumoral osteoblasts. The use of specific inhibitors and ROS scavengers suggested the involvement of oxidative stress, MMP alterations and ERK pathway in the apoptotic actions of this complex.

A series of hetaryl imidazoles with VEGF receptors I and II inhibitory activities was subjected to QSAR analysis employing molecular descriptors calculated using QSAR software Dragon. Quantitative models of good statistical significance were formulated for both the activities through stepwise multiple linear regression using the method of least squares and the generated models were evaluated for predictive ability employing cross validation procedure following a leave-one-out scheme. The interpretation of the QSAR models indicated that VEGF receptor II inhibitory activity of the title compounds is influenced by the number of hydrogen acceptor atoms and benzyl groups in the molecule whereas VEGF receptor I inhibitory activity is influenced by benzyl and aromatic functionalities and dipoles in the molecule. Furthermore, the QSAR model derived for Model for VEGF receptor II (cell based ELISA) inhibitory activity highlighted that electron withdrawing groups are beneficial and lipophilic moieties are detrimental to the activity.

Aldose Reductase (AR), the key enzyme of the polyol pathway catalyzes the reduction of glucose to sorbitol using nicotinamide adenine dinucleotide phosphate as an essential cofactor, has been demonstrated to play an important role in the pathogenesis of diabetic complications. Self Organizing Molecular Field Analysis (SOMFA), a novel threedimensional quantitative structure activity relationship (3D-QSAR) method has been used in present case to study the correlation between the molecular properties and the aldose reductase inhibitory activities on a series of 5-arylidine-2, 4- thiazolidinedione. SOMFA calculations for both shape and electrostatic potentials were carried out. The master grid maps derived from the best model has been used to display the contribution of both electrostatic and shape potential. The statistical results showed good cross-validated r2 CV, non cross-validated r2, F-test set and significant predictive ability indicated by r2 pred. All analysis of SOMFA models may provide useful information in the design of new aldose reductase inhibitors with improved spectrum of activity for management of diabetic complications.

The present study investigated the treatment effects of the immunosuppressive agent, tacrolimus (FK506), on rats with acute necrotizing pancreatitis (ANP). Methods: We used the taurocholate-induced model of acute necrotizing pancreatitis (ANP) in rats that were divided into seven groups: The sham group included animals that underwent sham operations. The ANP group contained ANP rats induced by taurocholate. The tacrolimus groups contained ANP rats treated with tacrolimus at three different time points (prior to the induction of ANP, immediately after the induction of ANP, one hour after the induction of ANP). The somatostatin group included ANP rats treated with somatostatin. The glucocorticoids group contained ANP rats treated with glucocorticoids. At 3, 6 and 12 hours after the induction of taurocholate, blood samples were collected for TNF-α, IL-1β and amylase assays, and lung and pancreas tissues were harvested for histopathological study and edema evaluation. Results: Tacrolimus administered prior to the induction of ANP and immediately after the induction of ANP caused a significant decrease in the twenty two-hour mortality rate (p<0.05). However, tacrolimus did not decrease the mortality rate when administered one hour after the induction of ANP (p>0.05). Treatment with all three drugs (tacrolimus, somatostatin and glucocorticoids) resulted in a significant decrease of serum amylase, lung edema, and serum TNF-α and IL-1β levels. Pancreatic and pulmonary morphological alterations were improved. Conclusions: Tancrolimus can decrease pancreatic and pulmonary injury. The effect of tacrolimus treatment is the same as that of somatostain and glucocroticoids. It is also more effective to administer the drug earlier.

A series of novel (±) 3-menthone semicarbazides (1-7) and thiosemicarbazides (8-14) were synthesized using an appropriate synthetic route and characterized by thin layer chromatography and spectral analysis. The anticonvulsant activity of synthesized compounds was established after intraperitoneal administration in three seizure models in mice which include maximal electroshock seizure (MES), subcutaneous pentylene tetrazole (scPTZ) induced seizure and minimal neurotoxicity test. Seven compounds exhibited protection in both models and N1 - (4-fluorophenyl) - N4- (menth-3- one) semicarbazide (4) emerged as the most active compound with MES ED50 of 44.15mg/kg and scPTZ ED50 of 38.68mg/kg at 0.25h duration. These compounds were found to elevate γ-amino butyric acid (GABA) levels in the midbrain region, thus indicating that (±) 3-menthone semicarbazides could be considered as a lead molecule in designing of a potent anticonvulsant drug.