5-Aminoisoquinolin-1-one (5-AIQ), a water-soluble inhibitor of the poly(ADP-ribose)polymerases (PARPs)

5-Aminoisoquinolin-1-one (5-AIQ) is a water-soluble inhibitor of the poly(ADP-ribose)polymerases (PARPs), lacking isoform-selectivity. Although of only moderate potency in vitro against PARP-1, it is highly active in many assays in cells and in models in vivo, indicating excellent uptake. Optimisation of the several synthetic sequences to 5-AIQ has led to development of a short and efficient route from 1-chloroisoquinoline. It has been used widely as a biochemical and pharmacological tool to study the effects of inhibition of the PARPs. It ameliorates the damage to cells and tissues following reperfusion of ischaemic tissue, showing significant protective activity in a rodent model of haemorrhagic shock at the remarkably low dose of 30 micro g Kg-1. Protection is also seen in models of myocardial infarction, ischaemic kidney and liver disorders, stroke and organ transplantation. Inhibition of PARP-1 by 5-AIQ causes down-regulation of the activity of NF-kappaB, which then down-regulates the expression of several gene products. Thus 5-AIQ has anti-inflammatory activity in vivo, through modulating the expression of cytokines and adhesion molecules. This indirect inhibition of expression is relevant in the activity of 5-AIQ in models of arthritis, Parkinson’s disease, multiple sclerosis, spinal cord injury, periodontitis and inflammatory conditions of the lung. Inhibition of expression of matrix metalloproteinases and other factors gives rise to anti-angiogenic activity and to remarkable anti-metastatic activity in a mouse model. Thus, although it has been overtaken by other PARP-inhibiting drugs in the oncological clinic, 5-AIQ remains a valuable tool to study the roles of PARPs in health and in diverse diseases

5-Aminoisoquinolin-1-one (5-AIQ), a water-soluble inhibitor of the poly(ADP-ribose)polymerases (PARPs)

5-Aminoisoquinolin-1-one (5-AIQ) is a water-soluble inhibitor of the poly(ADP-ribose)polymerases (PARPs), lacking isoform-selectivity. Although of only moderate potency in vitro against PARP-1, it is highly active in many assays in cells and in models in vivo, indicating excellent uptake. Optimisation of the several synthetic sequences to 5-AIQ has led to development of a short and efficient route from 1-chloroisoquinoline. It has been used widely as a biochemical and pharmacological tool to study the effects of inhibition of the PARPs. It ameliorates the damage to cells and tissues following reperfusion of ischaemic tissue, showing significant protective activity in a rodent model of haemorrhagic shock at the remarkably low dose of 30 micro g Kg-1. Protection is also seen in models of myocardial infarction, ischaemic kidney and liver disorders, stroke and organ transplantation. Inhibition of PARP-1 by 5-AIQ causes down-regulation of the activity of NF-kappaB, which then down-regulates the expression of several gene products. Thus 5-AIQ has anti-inflammatory activity in vivo, through modulating the expression of cytokines and adhesion molecules. This indirect inhibition of expression is relevant in the activity of 5-AIQ in models of arthritis, Parkinson’s disease, multiple sclerosis, spinal cord injury, periodontitis and inflammatory conditions of the lung. Inhibition of expression of matrix metalloproteinases and other factors gives rise to anti-angiogenic activity and to remarkable anti-metastatic activity in a mouse model. Thus, although it has been overtaken by other PARP-inhibiting drugs in the oncological clinic, 5-AIQ remains a valuable tool to study the roles of PARPs in health and in diverse diseases

Racemases and epimerases operating through a 1,1-proton transfer mechanism:Reactivity, mechanism and inhibition

Racemases and epimerases catalyse changes in the stereochemical configurations of chiral centres and are of interest as model enzymes and as biotechnological tools. They also occupy pivotal positions within metabolic pathways and, hence, many of them are important drug targets. This review summarises the catalytic mechanisms of PLP-dependent, enolase family and cofactor-independent racemases and epimerases operating by a deprotonation/reprotonation (1,1-proton transfer) mechanism and methods for measuring their catalytic activity. Strategies for inhibiting these enzymes are reviewed, as are specific examples of inhibitors. Rational design of inhibitors based on substrates has been extensively explored but there is considerable scope for development of transition-state mimics and covalent inhibitors and for the identification of inhibitors by high-throughput, fragment and virtual screening approaches. The increasing availability of enzyme structures obtained using X-ray crystallography will facilitate development of inhibitors by rational design and fragment screening, whilst protein models will facilitate development of transition-state mimics

Thiourea-functionalized aminoglutethimide derivatives as anti-Leishmanial agents

Aim: We aim to develop new anti-leishmanial agents against Leishmania major and Leishmania tropica. Materials &amp; methods: A total of 23 thiourea derivatives of (±)-aminoglutethimide were synthesized and evaluated for in vitro activity against promastigotes of L. major and L. tropica. Results &amp; conclusion: The N-benzoyl analogue 7p was found potent (IC 50 = 12.7 μM) against L. major and non toxic to normal cells. The docking studies, indicates that these inhibitors may target folate and glycolytic pathways of the parasite. The N-hexyl compound 7v was found strongly active against both species, and lacked cytotoxicity against normal cells, whereas compound 7r, with a 3,5-bis-(tri-fluoro-methyl)phenyl unit, was active against Leishmania, but was cytotoxic in nature. Compound 7v was thus identified as a hit for further studies.</p

Synthesis, urease inhibitory and anticancer evaluation of glucosamine-sulfonylurea conjugates

Urease catalyses the hydrolysis of urea to ammonia and carbon dioxide. This enzyme is important in the virulence of several human pathogens and urease activity in soil can cleave urea fertilisers prematurely, leading to waste of agricultural nitrogen. A series of arylsulfonylurea-glucosamine hybrid compounds were synthesised. Reaction of arylsulfonamides with phenyl chloroformate and 4-dimethylaminopyridine gave either phenyl N-(2,4-arylsulfonyl)carbamate 4-dimethylaminopyridinium salts or N-(4-arylsulfonyl)-4-dimethylaminopyridinium-1-carboxamide inner salts, depending on the substitution on the arylsulfonamide. Both types of intermediates, gave ester-protected arylsulfonylurea-glucosamines, when treated with 1,3,4,6-tetra-O-acetylglucosamine. Simple methanolysis gave the arylsulfonylurea-glucosamine hybrids as interconverting mixtures of anomers. Both the O-acetyl intermediates and the target arylsulfonylurea-glucosamines inhibited jack-bean urease with IC50 10–36 μM. This narrow range of values precluded the determination of structure-activity relationships and docking studies suggested several different optimum docking poses for the various analogues. No analogues showed radical-scavenging activity. Several compounds showed modest cytotoxic activity against renal carcinoma cells in the NCI 60-cell-line screen.</p