Multifunctional hybrid sulfonamides as novel therapeutic agents for Alzheimer's disease.

Aim: A breakthrough in modern medicine, in terms of treatment of Alzheimer's disease, is yet to be seen, as the scene is currently plagued with numerous clinical trial failures. Here, we are exploring multifunctional hybrid sulfonamides for their anti-Alzheimer activity due to the complex nature of the disease. Results & methodology: Compound 41 showed significant inhibition of MMP-2 (IC50: 18.24 ± 1.62 nM), AChE (IC50: 4.28 ± 0.15 µM) and BuChE (IC50: 1.32 ± 0.02 µM). It also exhibited a metal-chelating property, as validated by an in vitro metal-induced Aß aggregation assay using confocal fluorescence imaging. Whereas, MTT and DPPH assays revealed it to be nontoxic and neuroprotective with substantial antioxidant property. Conclusion: The present study puts forth potent yet nontoxic lead molecules, which foray into the field of multitargeted agents for the treatment of Alzheimer's disease.

Biological profiling of piperazinediones for the management of anxiety.

The anxiolytic effect of earlier reported piperazinediones was assessed by elevated plus maze (EPM), hole-board and open-field (OFT) tests. The rats were administered pretreatment of three different doses i.e. 2, 1 and 0.5 mg/kg of compounds 52, 53 and 55 for seven consecutive days. Compound 52 and diazepam showed increase in open arm entries, increase in time spent therein and total arm entries at 1 mg/kg dose. The compound also produced increase in the number of head dip, sniffing behavior and total number of squares crossed compared to diazepam. In OFT paradigm grooming behavior, number of central squares crossed and the time spent in central area did not reveal statistical differences for diazepam and compound 52 at 1 mg/kg dose. Flumazenil mediated antagonism experiments of these showed that they were acting through benzodiazepine site on GABAA receptor. The levels of 5HT and 5HIAA were estimated in amygdalar region. Level of 5HT was found to be equivalent in case of compound 52 and diazepam treatment at dose of 1 mg/kg. Interestingly, compound 52 did not display sedative effect at higher dose in both animal models. Thus, present study indicated that compound 52 produced anti-anxiety property through modulation of GABAergic transmission.

Development of Piperazinediones as dual inhibitor for treatment of Alzheimer's disease.

Novel multifunctional 3,6-Diphenyl-1,4-bis(phenylsulfonyl)piperazine-2,5-dione derivatives were designed and synthesized for the treatment of Alzheimer's disease (AD). The designed scaffold has blood brain barrier penetrating ability, acetylcholinesterase (AChE) and matrix metalloproteinase-2 (MMP-2) inhibition potential. Compounds 52 and 46 showed very significant inhibition against AChE, IC50 = 32.45 ±â€¯0.044, 28.65 ±â€¯0.029, BuChE, IC50 = 157.95 ±â€¯0.264, 160.58 ±â€¯0.082 and MMP-2, IC50 = 36.83 ±â€¯0.015, 19.57 ±â€¯0.005 (nM). In the enzyme kinetics study, lead molecule 46 showed non-competitive inhibition of AChE with Ki = 7 nM and competitive inhibition of MMP-2 with Ki = 20 nM. Compounds 52 and 46 inhibited AChE-induced Aß aggregation at 20 µM. The compounds also exhibited in-vitro antioxidant potential in DPPH assay. Further, compound 46 was found to be a promising neuroprotective agent in MC65 cells. Lead molecule 46 significantly enhanced working memory in scopolamine induced amnesia animal model at dose of 5 mg/kg dose. The mitochondrial membrane potential was restored in animals when treated with compounds 52 and 46.

Design, synthesis, and pharmacological evaluation of 2-amino-5-nitrothiazole derived semicarbazones as dual inhibitors of monoamine oxidase and cholinesterase: effect of the size of aryl binding site.

A series of 2-amino-5-nitrothiazole derived semicarbazones were designed, synthesised and investigated for MAO and ChE inhibition properties. Most of the compounds showed preferential inhibition towards MAO-B. Compound 4, (1-(1-(4-Bromophenyl)ethylidene)-4-(5-nitrothiazol-2-yl)semicarbazide) emerged as lead candidate (IC50 = 0.212 µM, SI = 331.04) against MAO-B; whereas compounds 21 1-(5-Bromo-2-oxoindolin-3-ylidene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC50 = 0.264 µM) and 17 1-((4-Chlorophenyl) (phenyl)methylene)-4-(5-nitrothiazol-2-yl)semicarbazide (IC50 = 0.024 µM) emerged as lead AChE and BuChE inhibitors respectively; with activity of compound 21 almost equivalent to tacrine. Kinetic studies indicated that compound 4 exhibited competitive and reversible MAO-B inhibition while compounds 21 and 17 showed mixed-type of AChE and BuChE inhibition respectively. Docking studies revealed that these compounds were well-accommodated within MAO-B and ChE active sites through stable hydrogen bonding and/or hydrophobic interactions. This study revealed the requirement of small heteroaryl ring at amino terminal of semicarbazone template for preferential inhibition and selectivity towards MAO-B. Our results suggest that 5-nitrothiazole derived semicarbazones could be further exploited for its multi-targeted role in development of anti-neurodegenerative agents. [Formula: see text] A library of 2-amino-5-nitrothiazole derived semicarbazones (4-21) was designed, synthesised and evaluated for in vitro MAO and ChE inhibitory activity. Compounds 4, 21 and 17 (shown) have emerged as lead MAO-B (IC50:0.212 µM, competitive and reversible), AChE (IC50:0.264 µM, mixed and reversible) and BuChE (IC50:0.024 µM, mixed and reversible) inhibitor respectively. SAR studies disclosed several structural aspects significant for potency and selectivity and indicated the role of size of aryl binding site in potency and selectivity towards MAO-B. Antioxidant activity and neurotoxicity screening results further suggested their multifunctional potential for the therapy of neurodegenerative diseases.