Dual-target ligand discovery for Alzheimer's disease: triphenylphosphoranylidene derivatives as inhibitors of acetylcholinesterase and β-amyloid aggregation

Alzheimer disease (AD) is one of the major neurodegenerative diseases that could not be prevented or completely cured and may lead to death. Here, we target AChE and β-amyloid proteins. Synthesising new triphenylphosphporanylidene derivatives based on the surveyed literature and testing their biological activity revealed promising results especially for the acetyl triphenylphosphoranylidene derivative 8c, which showed good inhibitor activity against AChE enzyme with IC₅₀ in the nanomolar range (97.04 nM); on the other hand, it showed poor selectivity for AChE versus butyrylcholinesterase but with some futural structural modification, this selectivity can be improved. 8c showed MMP-2 IC₅₀ of 724.19 nM and Aβ_1-42 aggregation IC₅₀ of 302.36 nM. A kinetic study demonstrated that compound 8c uncompetitively inhibited AChE. Moreover, derivative 8c showed low cytotoxicity, good in vivo behavioural studies including Y-maze and passive avoidance tests with activity similar to that of donepezil. Finally, in silico studies for 8c predict its good penetration into BBB and good binding affinity in the AChE binding site.

Fenofibrate ameliorates letrozole-induced polycystic ovary in rats via modulation of PPARα and TNFα/CD95 pathway

OBJECTIVE

Polycystic ovary syndrome (PCOS) is a prevalent endocrine health problem during the childbearing period that seriously affects fertility in females. Fenofibrate, a peroxisome proliferator-activated receptor-alpha (PPARα) agonist, showed beneficial effects in models of endocrine disturbances. Thus, we evaluated the potential therapeutic effect of fenofibrate in experimental PCOS.

MATERIALS AND METHODS

Rats received oral fenofibrate (300 mg/kg/day) for three weeks following a three-week PCOS induction regimen using oral letrozole (1 mg/kg/day). We determined the changes in body weight, levels of serum testosterone, insulin, anti-Müllerian hormone (AMH), ovarian malondialdehyde (MDA), superoxide dismutase (SOD), and tissue tumor necrosis factor-alpha (TNFα) and CD95 protein expressions. The tissue expression of interleukin-10 (IL10) and PPARα genes was determined.

RESULTS

Letrozole-treated rats showed successful induction of PCOS, confirmed by histopathology and significantly increased body weight, testosterone, insulin, AMH, and MDA, and decreased SOD. Ovaries of untreated PCOS rats showed increased TNFα and CD95 and decreased PPARα and IL10 expression. Administration of fenofibrate ameliorated the letrozole-induced PCOS changes.

CONCLUSIONS

Fenofibrate-mediated amelioration of PCOS in rats is attributed partly to its antioxidant, anti-inflammatory, and anti-apoptotic properties and activation of PPARα.

Synthesis, biological evaluation and molecular docking of new sulfonamide-based indolinone derivatives as multitargeted kinase inhibitors against leukemia

Series of novel sulfonamide-based 3-indolinones 3a-m and 4a-f were designed, synthesized and then their cytotoxic activity was evaluated against a panel of sixty cancer cell lines. This screening indicated that 4-(2-(5-fluoro-2-oxoindolin-3-ylidene)acetyl)phenyl benzenesulfonate (4f) possessed promising cytotoxicity against CCRF-CEM and SR leukemia cell lines with IC₅₀ values 6.84 and 2.97 µM, respectively. Further investigation of the leukemic cytotoxicity of compound 4f was carried out by performing PDGFRα, VEGFR2, Aurora A/B and FLT3 enzyme assays and CCRF-CEM and SR cell cycle analysis. These investigations showed that compound 4f exhibited pronounced dual inhibition of both kinases PDGFRα and Aurora A with potency of 24.15 and 11.83 nM, respectively. The in vitro results were supported by molecular docking studies in order to explore its binding affinity and its key amino acids interactions. This work represents compound 4f as a promising anticancer agent against leukemia.

Design, synthesis, biological evaluation, and molecular docking of new benzofuran and indole derivatives as tubulin polymerization inhibitors

Microtubules and the mitotic spindle have become an important target for cancer treatment due to their critical role in cell division. In this work, a novel series of benzofuran and indole derivatives were designed and synthesized, to be evaluated as tubulin polymerization inhibitors. 2-Acetylbenzofuran derivatives 1a,b and 3-acetylindole 1c were condensed with Wittig reagents 2a-d and Wittig-Horner reagents 3a-e to afford the respective 2-ethylidene derivatives 5a-j and 7a-e. Also, iminomethylene triphenylphosphine (2e) reacted with 1a,b to afford benzofuran-2-ylethylidene aniline derivatives 6a,b. In addition, compounds 1a,b reacted with trialkylphosphites 4a-c to give 1:1 adduct for which the Oxaphospholo[4,3-b]benzofuran-7-yl)diazene derivatives 8a-f, were assigned. The possible reactions mechanisms were discussed and structural reasoning for the new compounds were based upon spectroscopic data. Their antiproliferative activities against two cell lines namely, HepG2 and MCF7 cells were then evaluated. It was found that the benzofuran compounds 5b, 6a, and 8c exhibited the strongest antiproliferative activities against both cell lines compared to doxorubicin. By studying the mechanism of action, compound 6a showed good inhibition of tubulin polymerization which leads to mitotic spindle formation disruption, cell cycle arrest in the G2/M phase, and apoptosis of HepG2 cells. A conducted docking study confirmed the in vitro results indicating that compound 6a fitted properly at the colchicine binding site of tubulin. Based on these findings, compound 6a can be considered as a promising anticancer candidate that can be subjected for further development as a tubulin polymerization inhibitor for treating liver and breast cell carcinoma.

Role of nitric oxide donor in methotrexate-induced testicular injury via modulation of pro-inflammatory mediators, eNOS and P-glycoprotein

Methotrexate (MTX) is a widely used chemotherapeutic agent but its clinical use is challenged with different forms of toxicities including testicular injury. The aim of the current study was to evaluate the potential protective effect of potassium channel opener, nicorandil (NIC) (3 and 10 mg/kg/day) on MTX-induced testicular injury in a rat model. Rats were randomly divided into four groups (nine rats each) and treated for 2 weeks as follows: (I) normal control (CON group) received vehicle, (II) model group (MTX group) given MTX (20 mg/kg) single intraperitoneal (i.p.) injection dose on 11th day, (III) MTX + NLD group treated with NIC (3 mg/kg/day) orally for 2 weeks and MTX (20 mg/kg) single i.p. dose on 11th day, and (IV) MTX + NHD group treated with NIC (10 mg/kg/day) orally for 2 weeks and MTX (20 mg/kg) single i.p. injection on the 11th day. The testicular injury was assessed biochemically via serum testosterone, total antioxidant capacity, testicular oxidative stress parameters, P-glycoprotein, tumor necrosis factor-alpha, and interleukin-1β. Furthermore, histopathological evaluation, endothelial nitric oxide synthase (eNOS) immunoexpression, and detection of p53 expression level using Western blotting were performed. Results showed that MTX induced testicular injury which was proved by both biochemical and histopathological evaluations. Our results concluded that NIC pretreatment attenuated MTX-induced testicular injury via significantly increased eNOS immunoexpression, antiapoptotic, anti-inflammatory, and antioxidant properties. Interestingly, NIC high dose is more protective than low dose.

Synthesis, molecular docking and biological evaluation of 2-(thiophen-2-yl)-1H-indoles as potent HIV-1 non-nucleoside reverse transcriptase inhibitors

New 2-(thiophen-2-yl)-1H-indole derivatives bearing hydrophobic substituents at the 3-position were designed, synthesized and evaluated for their inhibition of HIV-1 reverse transcriptase (RT) enzyme. Dialkylphosphites (2a-c) or trialkylphosphites (3a-c) were reacted with 2-(thiophen-2-yl)-1H-indole-3-carbaldehyde (1) yielding the corresponding α-hydroxyphosphonate adducts (7a-7c). The reaction of compound 1 with the ylidenetriphenylphosphoranes (4a-4c) proceeds via Wittig mechanism giving the corresponding ethylenes (E, 8a-c). Compounds 8b,c were equally obtained upon reacting aldehyde 1 with the appropriate dialkylphosphonates 5a,b under the Horner-Wittig reaction conditions. On the other hand, the reaction of aldehyde 1 with diethyl cyanomethylene phosphonate (5c) yielded a mixture of the E-ethylene 10 and the cyanovinyl phosphonate 11. The thioaldehyde 12 was obtained upon refluxing aldehyde 1 with the Lawesson's reagent (LR, 6a) or with the Japanese reagent (JR, 6b) in dry toluene. Upon evaluation of HIV-1 Reverse Transcriptase enzyme inhibition, compound 8b (IC₅₀ = 2.93 nM) exhibited the superior HIV-1 RT inhibition and its potency was about 3-folds that of Efavirenz (IC₅₀ = 6.03 nM). Also, compounds 9a (IC₅₀ = 4.09 nM) and 12 (IC₅₀ = 3.54 nM) showed significantly higher inhibition potency. Moreover, compounds 7b (IC₅₀ = 7.48 nM), and 8a (IC₅₀ = 4.55 nM) showed potency not significantly different from that of Efavirenz. Molecular docking experiments on these potent compounds was in accordance with the in vitro data and confirmed binding of these compounds to the enzyme through ring-stacking and hydrogen bond interactions. According to these results, the new molecules would serve as potent HIV-1 NNRTIs inhibitors.

New phosphazine and phosphazide derivatives as multifunctional ligands targeting acetylcholinesterase and β-Amyloid aggregation for treatment of Alzheimer's disease

Phosphazine and phosphazide derivatives are described herein as a new class of selective and potent acetylcholinesterase (AChE) inhibitors and β-amyloid aggregation inhibitors. Phosphazines (5-7) were synthesized smoothly via a redox-condensation reaction of 1,2-bis(diphenylphosphino)ethane with different amines derivatives in the presence of dialkyl azodicarboxylate (Staudinger reaction) while phosphazides (8) via electrophilic attack of azido derivatives. Structures of the synthesized compounds were justified on the basis of compatible elementary and spectroscopic analyses. All the compounds were evaluated for their acetylcholinesterase inhibitory activity. The most three potent compounds (5b-c and 8b) showing AChE IC₅₀ values (29.85-34.96 nM) comparable to that of donepezil (34.42 nM) were subjected to further investigation by testing their butyrylcholinesterase, MMP-2 and self-induced Aβ aggregation inhibition activity. Especially, the coumarin phosphazide derivative (8b) presented the best AChE inhibition selectivity index (IC₅₀ = 34.96 nM, AChE/BuChE; 3.81) together with good inhibition ability against MMP-2 (IC₅₀ = 441.33 nM) and self-induced Aβ_1-42 aggregation (IC₅₀ = 337.77 nM). In addition, the inhibition of metal-induced Aβ aggregation by 8b was confirmed by thioflavine T fluorescence. The most potent effect of 8b was observed on the Zn²⁺-induced Aβ₄₂ aggregation. Kinetic study of compound 8b suggested it to be a competitive AChE inhibitor. Also, it specifically chelates metal and is predicted to be permeable to BBB. It also possesses low toxicity on SH-SY5Y neuroblastoma cells with a safety index of 15.37. In addition, it was demonstrated that compound 8b can improve the cognitive impairment of scopolamine-induced model in mice with % alternations and transfer latency time comparable to that of donepezil. Also, a docking study was carried out and it was in accordance with the in vitro results. These promising in vitro and in vivo findings highlight compound 8b as a possible drug candidate in searching for new multifunctional AD drugs.

Design, synthesis and biological evaluation of novel α-aminophosphonate oxadiazoles via optimized iron triflate catalyzed reaction as apoptotic inducers

α-aminophosphonate oxadiazoles (5a-m) were prepared in high yields by reacting of 1,3,4-oxadiazole acetohydrazide (3) with appropriate aldehydes and diethyl phosphite under Kabachnik-Fields conditions using Iron triflate as a catalyst. The reaction conditions were optimized using D-optimal experimental design. Possible reaction mechanisms were considered, and structures of the new products were based upon compatible elementary and spectroscopic evidence. In vitro antitumor activities of these compounds were evaluated against human cancer cell lines of colon (HCT116), breast (MCF7) and liver (HepG2) and compared with anticancer drug, Doxorubicin, employing standard MTT assay. Compounds 5i and 5l demonstrated good antiproliferative activities against HCT116 tumor cells comparable to doxorubicin with low cytotoxicity towards normal fetal colon cell (FHC). Additionally, their capacity to activate apoptosis cascade was studied in HCT116 cell line by investigating the activation of proteolytic caspases cascade, the levels of Cytochrome C, Bax and Bcl-2. Active caspase-3 level was enhanced by 6-8-folds in HCT116 cell line when stimulated with compounds 5i and 5l compared to the control. The level of Caspases 8 & 9 was also increased signifying that intrinsic and extrinsic pathways are both activated. They also induced Bax and down regulated Bcl-2 protein level in addition to over-expressing Cytochrome C level in HCT116 cell line. Also, HCT116 cell cycle was mainly arrested at the Pre-G1 and G2/M phases when treated with compounds 5i and 5l.

Synthesis and Pharmacological Evaluation of a Novel Series of Cyclopentenone Derivatives

A novel series of cyclopent-2-enone derivatives have been synthesised by the reaction of 4-hydroxy-3,4-diphenylcyclopent-2-enone, cyclic secondary amines, phosphorus reagents, hexamethylphosphoramide and Lawesson's reagent in boiling toluene/THF. The chemical structures of new compounds were identified by 1H NMR, 13C NMR, 31P NMR and mass spectra. Furthermore, the structure of one of the synthesised compounds has been confirmed using single crystal X-ray diffraction. The pharmacological evaluation results of antilung and anticolon carcinoma cell line properties for the products are discussed.

Chemistry of Phosphorus Ylides: Part 44 Reaction of 1-Trimethylsilyl-1H-Imidazole with Phosphorus Reagents. A Convenient Synthesis of Phosphorus Silyl Imidazoles

The reaction of 1-trimethylsilyl-1 H-imidazole with nucleophilic active phosphacumulenes afforded imidazole silyl phosphoranylidenes or imidazole phosphoranylidenes according to the reaction conditions. The reaction of hexaphenylcarbodiphosphorane with 1-trimethylsilyl-1 H-imidazole resulted in the formation of silyl phosphoranylidene phosphoranyl imidazole, silyl phosphoranylidene imidazole and triphenylphosphane. Moreover, Lawesson and Japanese reagents afforded imidazole phosphinothioic thioanhydrides.

Synthesis of novel pyrazole derivatives using organophosphorus, stibine, and arsine reagents and their antitumor activities

The reactions of 5-azido-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (azidopyrazole) with several classes of organophosphorus reagents: phosphonium ylides, Wittig-Horner reagents, dialkylphosphonates, trialkylphosphites, tris(dialkylamino)phosphanes, triphenylstibane, triphenylarsane, and Lawesson’s reagent are reported. Structural reasoning for the new products was based on compatible analytical and spectral data. The cytotoxic activity of most of the new products was evaluated against human breast carcinoma cell line (MCF7) and human hepatocellular carcinoma cell line(HepG2). Certain tested compounds showed promising results.

Reactions of ferrocenyl chalcones with hydrazines and active methylene compounds

Claisen-Schmidt condensation of ferrocenecarboxaldehyde (2b) with 2-acetylfuran (4) yielded (E)-3-ferrocenyl-1-(2-furyl)prop-2-en-1-one (E-5) together with 1,5-di(2-furyl)-3-ferrocenylpentane-1,5-dione (6). Reactions of the ferrocenyl chalcones 3a,b and 5 with hydrazine hydrate, phenyl hydrazine, ethyl acetoacetate, ethyl cyanoacetate and malononitrile, were also studied. Possible reaction mechanisms were discussed and structures of the new products were unambiguously characterized by common analytical and spectroscopic methods.

Chemistry of Phosphorus Ylides: Part 41 Synthesis of Antimicrobial Agents from the Reaction of Aminoantipyrine, Coumarin- and Quinoline-carbaldehyde with Phosphacumulene and Phosphaallene Ylides

Pyrrolo-pyrazoles were obtained from the reaction between phosphacumulenes and aminoantipyrine, while the reaction with the phosphaallene (hexaphenylcarbodiphosphorane ylide) afforded the azaphosphole and pyrazolo-phosphanylidene. The aminocoumarin carbaldehyde gave the chromeno-phosphanylidene and the chromeno-pyridinone, when it was allowed to react with phosphacumulenes. The reaction of chloroquinoline carbaldehyde with the phosphacumulenes, gave chloroquinoline phosphanylidenecyclobutane, while the reaction with phosphaallene resulted in the formation of oxaphosphetane, phosphanylidene ethenyl- and oxaphosphetyl-quinoline. The structure of cyclobutanedione was confirmed by X-ray crystallography. The antimicrobial activity of the new compounds is also reported.