Design, synthesis, in vitro antiproliferative evaluation and GSK-3ß kinase inhibition of a new series of pyrimidin-4-one based amide conjugates.

A new series of novel amide conjugates of pyrimidin-4-one and aromatic/heteroaromatic /secondary cyclic amines has been synthesized and their in vitro antiproliferative activities against a panel of 60 human cancer cell lines of nine different cancer types were tested at NCI. Among the synthesized compounds, compound (4i) showed significant anti-proliferative activity. Compound (4i) displayed most potent activity against the breast tumor cell line T-47D and CNS tumor cell line SNB-75 exhibiting a growth of 1.93 % and 14.63 %, respectively. ADMET studies of the synthesized compounds were also performed and they were found to exhibit good drug like properties. Compound (4i) was found to exhibit potential inhibitory effect over GSK-3ß with IC50 value of 71 nM. The molecular docking studies revealed that (4i) showed good binding affinity to GSK-3ß and revealed multiple H-bonding and p-cation interactions with important amino acid residues on the receptor site. Compound (4i) may thus serve as a potential candidate for further development of novel anticancer therapeutics.

Synthesis of benzimidazole-linked-1,3,4-oxadiazole carboxamides as GSK-3ß inhibitors with in vivo antidepressant activity.

Recent findings of potential implications of glycogen synthase kinase-3ß (GSK-3ß) dysfunction in psychiatric disorders like depression, have increased focus for development of GSK-3ß inhibitors with possible anti-depressant activity. Keeping this in view, we synthesized a series of benzimidazole-linked-1,3,4-oxadiazole carboxamides and evaluated them for in vitro GSK-3ß inhibition. Active compounds were investigated for in vivo antidepressant activity in Wistar rats. Docking studies of active compounds have also been performed. Among nineteen compounds synthesized, compounds 7a, 7r, 7j, and 7d exhibited significant potency against GSK-3ß in sub-micromolar range with IC50 values of 0.13 µM, 0.14 µM, 0.20 µM, 0.22 µM respectively and significantly reduced immobility time (antidepressant-like activity) in rats compared to control group. Docking study showed key interactions of these compounds with GSK-3ß. These compounds may thus serve as valuable candidates for subsequent development of effective drugs against depression and related disorders.

Oxazolo[4,5-b]pyridine-Based Piperazinamides as GSK-3ß Inhibitors with Potential for Attenuating Inflammation and Suppression of Pro-Inflammatory Mediators.

Recent studies reveal that glycogen synthase kinase-3ß (GSK-3ß) acts as a pro-inflammatory enzyme, and by inhibiting this kinase, inflammation can be controlled. In this regard, a series of 17 piperazine-linked oxazolo[4,5-b]pyridine-based derivatives was synthesized and evaluated for in vitro GSK-3ß inhibitory and in vivo anti-inflammatory activity. The compounds 7d, 7e, 7g, and 7c displayed the best GSK-3ß inhibitory activity among all the synthesized compounds, with corresponding IC50 values of 0.34, 0.39, 0.47, and 0.53 µM. Among the compounds 7d, 7e, 7g, and 7c examined for in vivo anti-inflammatory activity in the rat paw edema model, compound 7d exhibited maximum inhibition, reducing the paw volume by 62.79 and 65.91% at 3 and 5 h post-carrageenan administration, respectively, in comparison to indomethacin (76.74% at 3 h and 79.54% at 5 h after carrageenan administration). Furthermore, these compounds (7d, 7e, 7g, and 7c) were also found to substantially inhibit pro-inflammatory mediators, i.e., TNF-α, IL-1ß, and IL-6, ex vivo in comparison to indomethacin and did not pose any gastric ulceration risk, indicating the potential of this oxazolopyridine scaffold for the development of GSK-3ß inhibitors and their application as anti-inflammatory agents.

Natural and synthetic bioactive inhibitors of glycogen synthase kinase.

Glycogen synthase kinase-3 is a multi-functional serine-threonine kinase and is involved in diverse physiological processes, including metabolism, cell cycle, and gene expression by regulating a wide variety of known substrates like glycogen synthase, tau-protein and ß-catenin. Aberrant GSK-3 has been involved in diabetes, inflammation, cancer, Alzheimer's and bipolar disorder. In this review, we present an overview of the involvement of GSK-3 in various signalling pathways, resulting in a number of adverse pathologies due to its dysregulation. In addition, a detailed description of the small molecule inhibitors of GSK-3 with different mode of action discovered or specifically developed for GSK-3 has been presented. Furthermore, some clues for the future optimization of these promising molecules to develop specific drugs inhibiting GSK-3, for the treatment of associated disease conditions have also been discussed.

Synthesis of pyrimidin-4-one-1,2,3-triazole conjugates as glycogen synthase kinase-3ß inhibitors with anti-depressant activity.

GSK-3 specific inhibitors are promising candidates for the treatment of devastating pathologies such as diabetes, neurodegenerative diseases and cancers. We have synthesized a library of pyrimidin-4-one-1,2,3-triazole conjugates using click-chemistry approach and evaluated them as glycogen synthase kinase-3ß inhibitors. Compounds 3g, 3j, 3n and 3r were found to be most potent among the eighteen pyrimidin-4-one-1,2,3-triazole conjugates synthesized and they were further evaluated for their in vivo anti-depressant activity. Compound 3n (2-((1-(3,4-dimethylphenyl)-1H-1,2,3-triazol-4-yl)methylthio)-3-methyl-6-phenylpyrimidin-4(3H)-one) exhibited the most potent inhibitory activity against GSK-3ß with IC50 value of 82nM and was also found to exhibit significant antidepressant activity at 50mg/kg, when compared with fluoxetine, a known antidepressant drug. The molecular docking studies were performed to elucidate the binding modes of the compounds with the GSK-3ß target and two crucial interactions namely, hydrogen bond formation with Val 135 and Lys 183 residues in the active site of GSK-3ß were observed.

Synthesis of benzimidazole based thiadiazole and carbohydrazide conjugates as glycogen synthase kinase-3ß inhibitors with anti-depressant activity.

A series of benzimidazole based thiadiazole and carbohydrazide conjugates have been synthesized and evaluated for inhibition of glycogen synthase kinase-3ß and anti-depressant effect. Compounds 4f, 4j, 5b, 5g and 5i were found to be the most potent inhibitors of GSK-3ß in vitro amongst the twenty-five benzimidazole based thiadiazole and carbohydrazide conjugates synthesized. Compound 5i was also found to exhibit significant antidepressant activity in vivo at 50mg/kg, when compared to fluoxetine, a known antidepressant drug. The molecular docking studies revealed multiple hydrogen bond interactions by the synthesized compounds with various amino acid residues, viz, ASP-133, LYS-183, PRO-136, VAL-135, TYR-134, or LYS-60 at the GSK-3ß receptor site.

Synthesis of Novel Oxazolo[4,5-b]pyridine-2-one based 1,2,3-triazoles as Glycogen Synthase Kinase-3ß Inhibitors with Anti-inflammatory Potential.

A novel series of oxazolo[4,5-b]pyridine-2-one based 1,2,3-triazoles has been synthesized by click chemistry approach and evaluated for in vitro GSK-3ß inhibitory activity. Compound 4g showed maximum inhibition with IC50 value of 0.19 µm. Keeping in view the effect of GSK-3ß inhibition on inflammation, compounds 4g, 4d, 4f, 4i, 4n and 4q exhibiting significant GSK-3ß inhibition were examined for in vivo anti-inflammatory activity in rat paw edema model. The compounds 4g, 4d, 4f and 4i showed pronounced in vivo anti-inflammatory activity (76.36, 74.54, 72.72 and 70.90%, respectively, after 5h post-carrageenan administration) and were further found to inhibit the pro-inflammatory mediators, viz. NO, TNF-α, IL-1ß, and IL-6 substantially in comparison with indomethacin, an anti-inflammatory drug as well as SB216763, a GSK-3ß inhibitor, reported to exert a similar effect. Histopathology studies confirmed the tolerance of gastric mucosa to these compounds.

Synthesis of Novel Pyrimidin-4-One Bearing Piperazine Ring-Based Amides as Glycogen Synthase Kinase-3ß Inhibitors with Antidepressant Activity.

Novel pyrimidin-4-one derivatives have been synthesized using EDC coupling and evaluated as glycogen synthase kinase-3ß (GSK-3ß) inhibitors. Among all the synthesized compounds, compound 5 (3-methyl-6-phenyl-2-(piperazin-1-yl)-3,4-dihydropyrimidin-4-one) exhibited the most potent inhibitory activity against GSK-3ß with IC50 value of 74 nm. The molecular docking studies were performed to elucidate the binding modes of the compounds with the target, and a crucial interaction involving hydrogen bond formation with Val-135 to the active site of GSK-3ß was observed. Furthermore, the synthesized compounds were subjected to in vivo evaluation of their antidepressant activity, and compound 5 showing highest inhibition of GSK-3ß was also found to significantly reduce the duration of immobility at 50 mg/kg, when compared with fluoxetine, a known antidepressant drug. The results of our study suggest that compound 5 may serve as a valuable template for the design and development of inhibitors of GSK-3ß with antidepressant activity.