Quercetin-1,2,3-Triazole Hybrids as Multifunctional Anti-Alzheimer's Agents

The number of patients with Alzheimer's disease (AD) continues to rise and, despite the efforts of researchers, there are still no effective treatments for this multifaceted disease. The main objective of this work was the search for multifunctional and more effective anti-Alzheimer agents. Herein, we report the evaluation of a library of quercetin-1,2,3-triazole hybrids (I-IV) in antioxidant, hydrogen peroxide-induced oxidative stress protection, and cholinesterases (AChE and BuChE) inhibitory activities. Hybrids IIf and IVa-d showed potent in vitro inhibitory activity on eqBuChE (IC50 values between 11.2 and 65.7 μM). Hybrid IIf, the best inhibitor, was stronger than galantamine, displaying an IC50 value of 11.2 μM for eqBuChE, and is also a competitive inhibitor. Moreover, toxicity evaluation for the most promising hybrids was performed using the Artemia salina toxicity assay, showing low toxicity. Hybrids IIf, IVb, and IVd did not affect viability at 12.5 μM and also displayed a protective effect against oxidative stress induced by hydrogen peroxide in cell damage in MCF-7 cells. Hybrids IIf, IVb, and IVd act as multifunctional ligands in AD pathologies.

Synthesis and Antiproliferative Activity of Novel Quercetin-1,2,3-Triazole Hybrids using the 1,3-Dipolar Cycloaddition (Click) Reaction

Twenty-three new quercetin-1,2,3-triazole hybrids were synthesized in good to quantitative yields via Cu(I)-catalyzed azide-alkyne cycloaddition reaction under microwave irradiation. These new hybrids contain a 1,4-disubstituted 1,2,3-triazole ring at the 3-OH position of quercetin whilst the remaining hydroxyl groups were either protected as methyl or benzyl groups or left unprotected. All the quercetin-1,2,3-triazole hybrids I–IV were evaluated against REM-134 canine mammary cancer cell line, which is used as a translational model for human breast cancer. These new analogues exhibit potent antiproliferative activity against this cancer cell line. Furthermore, the results show that some of the new quercetin-1,2,3-triazole hybrids have better activity than quercetin. Our best inhibitors displayed IC50 values in the range of 41–180 nM, and undoubtedly will have an important impact on the treatment of both canine and human breast cancer.

[Pulmonary embolism as a presentation of nephrotic syndrome]

BACKGROUND

Nephrotic syndrome (NS) in adults is defined by proteinuria>3g/24h or 50mg/kg/d, hypoproteinemia<60g/24h and hypoalbuminemia<30g/L. The final diagnosis is guided by the histopathology evidence when a renal biopsy is possible. The consequences of NS are multiple: high blood pressure, undernutrition, infections and a hypercoagulable state.

OBSERVATION

We report the case of a patient presenting with thromboembolic disease, occurring in the absence of other thromboembolic risk factors, which revealed NS with spontaneously favorable evolution.

CONCLUSION

Thromboembolic disease in NS is frequent but underestimated and may remain underdiagnosed. Thorough investigation - including serum protein levels and testing for proteinuria - are essential in thromboembolism, as is excluding cancer or another cause. The treatment of thromboembolic disease in NS is based on anticoagulation for as long as the NS persists. There is no consensus about primary prophylaxis but an albumin level below 20g/L should be considered as a risk factor of thrombosis and prophylactic anticoagulation should be started.