Design, synthesis, and biological evaluation of thienopyrimidine derivatives as multifunctional agents against Alzheimer's disease

A series of 12 S-substituted tetrahydrobenzothienopyrimidines were designed and synthesized based on the donepezil scaffold. All the newly synthesized compounds were evaluated for their acetylcholinesterase (AChE) inhibitory activity and the most active compounds were tested for their butyrylcholinesterase (BuChE) inhibitory activity. Moreover, all the synthesized compounds were evaluated for their inhibitory effects against Aβ aggregation and antioxidant activity using the oxygen radical absorbance capacity method. Compounds 4b, 6b, and 8b displayed the most prominent AChE inhibitory action comparable to donepezil. Compound 6b showed the greatest AChE inhibitory action (IC50  = 0.07 ± 0.003 µM) and the most potent BuChE inhibitory action (IC50  = 0.059 ± 0.004 µM). Furthermore, the three compounds exhibited significant antioxidant activity. Compounds 6b and 8b exerted more inhibitory action on Aβ aggregation than donepezil. The cytotoxic activity of compounds 4b, 6b, and 8b against the WI-38 cell line in comparison with donepezil was examined using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay. The results revealed that compounds 6b and 8b were less cytotixic than donepezil, while compound 4b showed nonsignificant cytotoxicity compared to donepezil. For more insights about the binding patterns of the most promising compounds (4b, 6b, and 8b) with the AChE at molecular levels; molecular docking and molecular dynamics simulations were performed. The density functional theory calculations and absorption, distribution, metabolism, excretion and toxicity properties were described as well. The results highlighted compound 6b, which incorporates a phenylpiperazine moiety coupled to a thienopyrimidone scaffold via two-atom spacer, to be a promising multifunctional therapeutic agent for the treatment of Alzheimer's disease. It is a potent dual AChE and BuChE inhibitor. Furthermore, it had stronger Aβ aggregation inhibitory action than donepezil. Additionally, compound 6b exerted significant antioxidant activity.

Development of new Alzheimer's disease drug candidates using donepezil as a key model

Alzheimer's disease (AD) is one of the most prevalent geriatric diseases and a significant cause of high mortality. This crippling disorder is becoming more prevalent at an unprecedented rate, which has led to an increase in the financial cost of caring. It is a pathologically complicated, multifactorial disease characterized by β-amyloid precipitation, β-amyloid oligomer production, decrease in cholinergic function, and dysregulation of other neurotransmitter systems. Due to the pathogenic complexity of AD, multitarget drugs that can simultaneously alternate multiple biological targets may enhance the therapeutic efficacy. Donepezil (DNP) is the most potent approved drug for the treatment of AD. It has a remarkable effect on a number of AD-related processes, including cholinesterase activity, anti-Aβ aggregation, oxidative stress, and more. DNP resembles an excellent scaffold to be hybridized with other pharmacophoric moieties having biological activity against AD pathological factors. There have been significant attempts made to modify the structure of DNP to create new bioactive chemical entities with novel structural patterns. In this review, we highlight recent advances in the development of multiple-target DNP-hybridized models for the treatment of AD that can be used in the future in the rational design of new potential AD therapeutics. The design and development of new drug candidates for the treatment of AD using DNP as a molecular scaffold have also been reviewed and summarized.

The extent of involvement of ouabain, hippocampal expression of Na+/K+-ATPase, and corticosterone/melatonin receptors ratio in modifying stress-induced behavior differs according to the stressor in context

The aim of this study was to assess the effect of two types of stressors, regarding the extent of involvement of ouabain (OUA), hippocampal sodium/potassium ATPase (NKA) expression, and the hippocampal corticosterone receptors (CR)/melatonin receptors (MR) expression ratio, on the behavioral and cardiovascular responses and on the hippocampal cornu ammonis zone 3 (CA3) and dentate gyrus (DG). Thirty adult male Wistar albino rats aged 7-8 months were exposed to either chronic immobilization or a disturbed dark/light cycle and treated with either ouabain or vehicle. In the immobilized group, in the absence of hippocampal corticosterone (CORT) changes, rats were non-responsive to stress, despite experiencing increased pulse rate, downregulated hippocampal sodium/potassium pump, and enhanced hippocampal CR/MR expression ratio. Prolonged darkness precipitated a reduced upright attack posture, with elevated CORT against hippocampal MR downregulation. Both immobilization and, to a lesser extent, prolonged darkness stress resulted in histopathological and ultrastructural neurodegenerative changes in the hippocampus. OUA administration did not change the behavioral resilience in restrained rats, despite persistence of the underlying biochemical derangements, added to decreased CORT. On the contrary, with exposure to short photoperiods, OUA reverted the behavior towards a combative reduction of inactivity, with unvaried CR/MR and CORT, while ameliorating hippocampal neuro-regeneration, with co-existing NKA and MR repressions. Therefore, the extent of OUA, hippocampal NKA expression, and CR/MR expression, and subsequent behavioral and cardiac responses and hippocampal histopathology, differ according to the type of stressor, whether immobilization or prolonged darkness.

Design, synthesis, and biological evaluation of thienopyrimidine and thienotriazine derivatives as multitarget anti-Alzheimer agents

A series of tetrahydrobenzothienopyrimidines and tetrahydrobenzothienotriazines incorporating a pharmacophore from donepezil molecule were designed and synthesized. The 12 newly synthesized compounds were screened for their inhibition activity against acetylcholinesterase enzyme (AChE). Compounds that exerted the most potent AChE inhibitory action were further evaluated for their BChE inhibitory activity. In addition, the inhibitory effects of all newly synthesized compounds on Aβ and reactive oxygen species were assessed. Compounds 4d, 10b, and 10c showed potent inhibitory activity on AChE comparable to donepezil. Compound 10b (IC₅₀  = 0.124 ± 0.006 nM) showed the greatest AChE inhibitory action and the most potent BChE inhibitory action (IC₅₀  = 0.379 ± 0.02 nM). These three compounds showed more inhibitory action on Aβ accumulation than donepezil. Moreover, they showed potent antioxidant activity. The binding pattern of compounds 4d and 10b into AChE active site rationalized their remarkable AChE inhibitory activity. Taken together, these results indicated that these derivatives could be promising multifunctional agents for Alzheimer's disease management.

Synthesis and Cytotoxicity Evaluation of Novel Indole Derivatives as Potential Anti-Cancer Agents

BACKGROUND

Marine sponges and tunicates have been a wealthy source of cytotoxic compounds such as indole alkaloids. Most of the indole alkaloids show in vitro cytotoxic and antineoplastic activities against a wide range of cancer cell lines.

OBJECTIVE

Three series of bioisosteres of marine indole alkaloids (meridianins) were synthesized and the compounds were tested for their in vitro anti-proliferative activity against HCT-116 cellline. In the design of the targeted analogues, the 2-aminopyrimidine ring of merdianins was replaced with 5-aminopyrazole, pyrazolo[1,5-a]pyrimidine and pyrazolo[3,4-b]pyridine rings.

RESULTS

The cytotoxic screening of the synthesized compounds revealed that pyrazolo[1,5- a]pyrimidines (compounds 9c and 11a) had the most potent cytotoxic activity with IC50 = 0.31 μM and 0.34 μM respectively. Compounds 9c and 11a were further investigated for their kinase inhibitory potencies toward six kinases (CDK5/p25, CK1ð/ε, GSK-3α/β, Dyrk1A, Erk2, and CLK1). They exhibited effective inhibition of GSK-3α/β (IC50 = 0.196 μM and 0.246 μM, respectively) and Erk2 (IC50 = 0.295 μM and 0.376 μM, respectively).

CONCLUSION

Meridianins emerged as promising lead structures that need further development to obtain more selective and potent cytotoxic agents. One of these modifications involved the replacement of 2-aminopyrimidinyl ring of meridianins with other heterocyclic rings. Both pyrazolo[ 1,5-a]pyrimidine and pyrazolo[3,4-b]pyridine rings showed promising cytotoxic activity compared to the five membered 5-aminopyrazole.

Synthesis, Characterization and Cytotoxicity of Substituted [1]Benzothieno[3,2-e][1,2,4]triazolo [4,3-a]pyrimidines

A new series of 4-benzyl-6,7,8,9-tetrahydro[1]benzothieno[3,2-e][1,2,4]triazolo[4,3-a]pyrimidines was synthesized motivated by the widely reported anticancer activity of thieno[2,3-d]pyrimidines and triazolothienopyrimidines. The in vitro cytotoxic activity of some selected compounds was evaluated against two human cell lines: prostate cancer (PC-3) and colon cancer (HCT-116). A preliminary study of the structure-activity relationship of the target compounds was discussed. Most of the synthesized compounds showed remarkable activity on the tested cell lines, while compound 16c had the highest potency against the PC-3 cell line with an IC50 of 5.48 μM compared to Doxorubicin (IC50 = 7.7 μM), the reference standard used in this study. On the other hand, 6c and 18c were the most active against HCT-116 (IC50 = 6.12 and 6.56 μM, respectively) relative to IC50 = 15.82 μM of the standard. Thus, some of the synthesized thienopyrimidine derivatives, specially 6c, 16c and 18c, have the potential to be developed into potent anticancer agents.

Application of Resin-Bound Reagents for the Synthesis of Benzimidazole Derivatives

In an efficient exploitation of solid-phase chemistry, this work describes the preparation of the new resin-bound 4-( N-arylamino)-3-aminobenzoates and their successful cyclocondensations with the sodium bisulfite adducts of different aldehydes and triethyl orthoformate or triethyl orthoacetate, followed by resin cleavage to produce the target 1,2-diaryl- and 1-aryl-2-(un)substituted benzimidazole-5-carboxylic acid derivatives, respectively. In another variation, the cyclocondensation of the resin-bound 4-( N-arylamino)-3-aminobenzoates with carbon disulfide afforded the corresponding resin-bound thioxobenzimidazoles, which upon cleavage gave the corresponding 2-thioxobenzimidazoles. S-Alkylation of the resin-bound thioxobenzimidazoles with benzyl chloride and 4-bromophenacyl bromide furnished 2-benzylsulfanyl benzimidazoles and 4-bromophenyl-2-oxoethylsulfanyl-benzimidazoles, respectively. Reacting the resin-bound 4-( N-arylamino)-3-aminobenzoates with phenyl isothiocyanate gave the open-form 4-(arylamino)-3-(3-phenylthioureido) benzoic acids. Moreover, the reaction of the resin-bound 4-( N-arylamino)-3-aminobenzoates with N,N-carbonyldiimidazole yielded the corresponding 2-bezimidazolones.

Convenient synthesis, characterization, cytotoxicity and toxicity of pyrazole derivatives

3-Methyl-1H-pyrazol-5(4H)-one (1) was used as a template to develop new anticancer compounds and investigate their SAR. The ring modification of compound 1 occurred through its reaction with aromatic aldehydes and different reagents to afford the corresponding 6-oxopyrano[2,3-c]pyrazoles4a-c and their amino analogues 6-aminopyrano[2,3-c]pyrazoles6a-c, 8; the pyrazolopyrano[2,3-b]pyridines 10a-c and the chromenopyrano[2,3-c]pyrzolones13, 14. The reaction of compound 1 with thiourea and appropriate aromatic aldehydes afforded the pyrazolo[3,4-d]pyrimidine derivatives 17a-c. On the other hand, the pyrazolo[3,4-d]thiazole derivatives 22a-d were obtained via the reaction of 1 with sulpher and aryl isothiocyanates in presence of triethylamine. The reaction of compound 1 with phenylisothiocyanate followed by treatment with the a-halocarbonyl compounds 24a-c afforded the thiazole derivatives 25a-c. The synthesized products were evaluated for their cytotoxicity against cancer and normal cell lines. Most compounds showed significant anticancer activity without affecting the normal fibroblast cells. The toxicity of the mostpontent cytotoxic compounds was measured using Brine-Shrimp Lethality Assay.

Synthesis and biological evaluation of thiophene derivatives as acetylcholinesterase inhibitors

A series of new thiophene derivatives has been synthesized using the Gewald protocol. The acetylcholinesterase inhibition activity was assayed according to Ellman’s method using donepezil as reference. Some of the compounds were found to be more potent inhibitors than the reference. 2-(2-(4-(4-Methoxyphenyl)piperazin-1-yl)acetamido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (IIId) showed 60% inhibition, compared to only 40% inhibition by donepezil.

Synthesis of new indole derivatives structurally related to donepezil and their biological evaluation as acetylcholinesterase inhibitors

New series of indole derivatives analogous to donepezil, a well known anti-Alzheimer and acetylcholinesterase inhibitor drug, was synthesized. A full chemical characterization of the new compounds is provided. Biological evaluation of the new compounds as acetylcholinesterase inhibitors was performed. Most of the compounds were found to have potent acetylcholinesterase inhibitor activity compared to donepezil as standard. The compound 1-(2-(4-(2-fluorobenzyl) piperazin-1-yl)acetyl)indoline-2,3-dione (IIId) was found to be the most potent.

Ultrasonic assisted dyeing: dyeing of acrylic fabrics C.I. Astrazon Basic Red 5BL 200%

The dyeing of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% has been studied with both conventional and ultrasonic techniques. The effect of dye concentration, dye bath pH, ultrasonic power, dyeing time and temperature were studied and the resulting shades obtained by dyeing with both techniques were compared. Colour strength values obtained were found to be higher with ultrasonic than with conventional heating. The results of fastness properties of the dyed fabrics were studied. X-ray and Scanning Electron Microscope SEM were carried out on dyed samples using both methods of dyeing to find out an explanation for the better dyeability of acrylic fabrics with (US) method. Dyeing kinetics of acrylic fabrics using C.I. Astrazon Basic Red 5BL 200% using conventional and ultrasonic conditions were compared. The time/dye-uptake isotherms are revealing the enhanced dye-uptake in the second phase of dyeing. The values of dyeing rate constant, half-time of dyeing and standard affinity and ultrasonic efficiency have been calculated and discussed.

Ultrasonic dyeing of cationized cotton fabric with natural dye. Part 1: cationization of cotton using Solfix E

The dyeing of cationized cotton fabric with Solfix E using colouring matter extracted from Cochineal dye has been studied using both conventional and ultrasonic techniques. Factors affecting dye extraction such as ultrasound power, particle size, extraction temperature and time were studied. The results indicated that the extraction by ultrasound at 300 W was more effective at lower temperature and time than conventional extraction. The effect of various factors of dye bath such as pH, salt concentration, ultrasound power, dyeing time and temperature were investigated. The colour strength values obtained were found to be higher with ultrasound than with conventional techniques. The results of fastness properties of the dyed fabrics were fair to good. The scanning electron microscope (SEM) images of the morphological and X-ray analyzes were measured for cationized cotton fabrics dyed with both conventional and ultrasound methods, thus showing the sonicator efficiency.

Removal of azo and anthraquinone dyes from aqueous solutions by Eichhornia Crassipes

The rate of adsorption of two azo and four anthraquinone anionic dyes on Eichhornia Crassipes (E.C.) has been studied. Raw E.C. and three aminated derivatives of E.C. with different nitrogen percent were used as dye adsorbents. The parameters studied include the amount of substrate, shaking time, chemical structure, concentration of dyestuff and pH of dyeing bath. Simple kinetic adsorption models of dynamics and adsorption parameters for the Langmuir and Freundlich isotherms were determined. A higher nitrogen percent of aminated E.C. showed a higher adsorption capacity than other derivatives. The kinetic adsorption models indicate that the decolourization was complete in a relatively short time (10 min) and the reaction taking place is of the first order. The equilibrium data fit well with the Freundlich model of adsorption for the six dyes. Only dye IV (C.I.A Acid Blue 25) conform both Freundlich and Langmuir adsorption isotherms.

Effect of cyclophosphamide-mediated immunodeficiency on murine Schistosomiasis mansoni

Four groups of female C57BL/6 mice were used. The first group was infected with 500 unattenuated cercariae. The second group was immunosuppressed by cyclophosphamide (Cy) before infection with the same dose of cercariae. The third group was exposed to 500 partially attenuated cercariae while the fourth group was immunosuppressed with (Cy) before exposure to 500 partially attenuated cercariae. In response to infection with either unattenuated or partially attenuated cercariae, the total worm burden was significantly reduced. In the meantime, the level of serum specific anti-SWAP IgG1 was significantly higher and a specific band at 32 kDa was recognized in the infected groups (first and third) compared to that in the immunosuppressed groups (second and fourth). Scanning electron microscopy observations revealed severe damage and deformities on the tegument of worms of the third group compared to less damage detected on the tegument of worms in the fourth group. No obvious changes could be detected on the tegument of worms developed from the second group compared to the first group (controls). These observations taken together indicate that the high level of anti-SWAP IgG1 may have a role in the elimination of schistosomes after primary infection of mice with either unattenuated or partially attenuated S. mansoni cercariae. Moreover, this immunoglobulin together with UV-induced attenuation produce severe damage on the tegument of worms developed from mice exposed to partially attenuated cercariae.

Ultrastructural observations in Darier's disease

Two patients with Darier's disease--diagnosed clinically by the presence of characteristic keratotic papules in seborrheic areas--were biopsied for light- and electron-microscopic studies. Light microscopy revealed typical histologic features of Darier's disease. Ultrastructural studies showed the presence of cytoplasmic processes projecting from the basal keratinocytes (basal keratinocyte herniations) into the underlying dermis through small defects in the basal lamina, which was intact in some areas but in other locations showed thickening, irregularity, and replication. Widening of the lamina lucida with partial or complete disappearance of hemidesmosomes were noted in many areas.

Effects of a lengthy period of undernutrition from birth and subsequent nutritional rehabilitation on the synapse: granule cell neuron ratio in the rat dentate gyrus

Recent evidence showing alterations in spatial memory due to a period of undernutrition during early life has implicated the hippocampus as one of the brain centres that may be particularly adversely affected. However, there are very few quantitative morphological studies that have examined the neuronal and synaptic populations of the hippocampi from undernourished animals. We decided to carry out such experiments, paying particular attention to the granule cell of the dentate gyrus. Male rats were undernourished from the 18th day of gestation until 21, 75, or 150 days of age. Some of these previously undernourished rats were nutritionally rehabilitated between 150 and 250 days of age. Groups of well-fed control and experimental rats were killed by intracardiac perfusion with 2.5% sodium-cacodylate-buffered glutaraldehyde. The right hippocampus from each rat was dissected out and processed for electron microscopy. Stereological procedures at the light and electron microscopical levels were used to estimate the numerical densities of granular cell neurons and molecular layer synapses in the dorsal lip of the dentate gyrus. These estimates were used to calculate synapse: neuron ratios. There were 5,056 +/- 347 (mean +/- SE) and 5,002 +/- 190 synapses per neuron in 21-day-old control and undernourished rats, respectively. By 75 days these values had increased to 9,215 +/- 588 and 6,683 +/- 237. The difference was statistically significant. By 150 days of age the value for control animals had fallen once again to 6,518 +/- 209 whereas undernourished rats had increased slightly to 7,689 +/- 288 (P less than .01); 250-day-old rats, previously undernourished from birth to 150 days of age, showed a substantial increase in the synapse: neuron ratio during the period of nutritional rehabilitation. Thus these nutritionally rehabilitated rats had 9,407 +/- 365 synapses per neuron whereas age-matched controls had only 6,323 +/- 239 (P less than .01). These results indicate that the rat dentate gyrus is vulnerable to undernutrition even during the postweaning period and that a lengthy period of undernutrition can alter the developmental growth curve for synapse: neuron ratios.

Effect of praziquantel on certain immune responses of schistosomal Egyptian patients. I. Changes of specific immunoglobulins

Specific antischistosomal IgG, IgM, and IgE were estimated by ELISA in 117 rural school students before specific treatment with praziquantel monthly for 3-4 months thereafter. IgG and IgM were estimated as percentage of bound antibodies. IgE was estimated by avidin-biotin ELISA (AB-ELISA) as IU/ml using a panel of known IgE standards. Soluble surface Schistosoma mansoni adult worm antigen was used for all estimates. Total IgE was estimated in a smaller group by an ELISA kit. The percentage of specific IgE was calculated. A group of endemic controls (22 students) and non-endemic controls (17 cases) were included. Statistical analysis of results showed the specific immunoglobulins to be significantly reduced 2 months after treatment of the schistosomal cases. These reduced levels, however, were still significantly higher than those of controls. The presence of early hepatosplenomegaly and the co-existence of other parasites had no significant influence on the results. No correlation could be established between the levels of specific antischistosomal IgG, M and E and the intensity of infection. The significance of these results is discussed.

Synthesis of quinoline-Mannich bases of possible antimalarial activity

For possible antimalarial activity, a series of some 4-substituted aminoquinoline Mannich bases (5a-e) was synthesized. The antimalarial evaluation showed that compound 5b was active against Plasmodium berghei in mice at a dose of 100 mg/kg.

Multiple choice questions for assessment of primary FFARCS course students

Multiple choice questions have been used to assess the progress of 105 postgraduate anaesthetic students over three successive academic years, at the University of Liverpool. Analysis of the results of these tests had revealed a good correlation existing between the MCQ scores obtained and success or failure in the Colleges' Primary FFARCS examinations. Both retrospective and prospective analyses are presented. The value of serial MCQ tests is discussed in relation to encouraging and discouraging students in sitting postgraduate examinations. Analyses of these tests are also of value in planning teaching programmes, assessment of teaching and predicting overall successes and failure of students.

A comparison of buprenorphine and pethidine for immediate postoperative pain relief by the i.v. route

A comparison was made of the relief of pain after operation, obtained following the i.v. administration of buprenophrine and pethidine in 60 patients with lower abdominal incisions. No difference could be detected between the maximum analgesia produced by eigher drug, but analgesia following buprenorphine appeared to last about four times as long as that following pethidine. When the drugs were compared on a "dose per body weight" basis the results supported a ratio of potency in the order of 1 : 200 in favour of buprenorphine. Vomiting, drowsiness and dizziness were less frequent following buprenorphine, but a similar frequency of nausea was observed with both agents. Marked miosis occurred 5--10 min after the i.v. injection of buprenorphine, but no serious side-effects were observed with either drug. The i.v. injection of buprenorphine, but no serious side-effects were observed with either drug. The i.v. administration of buprenorphine appeared to be effective in the management of pain after operation in patients with lower abdominal incisions.