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Abstract Alzheimer's disease is a devastating neurodegenerative disorder characterized by memory loss and cognitive decline. New AD treatments are essential, and drug repositioning is a promising approach. In this study, we combined ligand-based and structure-based approaches to identify potential candidates among FDA-approved drugs for AD treatment. We used the human acetylcholinesterase receptor structure (PDB ID: 4EY7) and applied Rapid Overlay of Chemical Structures and Swiss Similarity for ligand-based screening.Computational shape-based screening revealed 20 out of 760 FDA approved drugs with promising structural similarity to Donepezil, an AD treatment AChE inhibitor and query molecule. The screened hits were further analyzed using docking analysis with Autodock Vina and Schrodinger glide. Predicted binding affinities of hits to AChE receptor guided prioritization of potential drug candidates. Doxazosin, Oxypertine, Cyclopenthiazide, Mestranol, and Terazosin exhibited favorable properties in shape similarity, docking energy, and molecular dynamics stability.Molecular dynamics simulations confirmed the stability of the complexes over 100 ns. Binding free energy analysis using MM-GBSA indicated favourable binding energies for the selected drugs. ADME, formulation studies offered insights into therapeutic applications and predicted toxicity.This comprehensive computational approach identified potential FDA-approved drugs (especially Doxazosin) as candidates for repurposing in AD treatment, warranting further investigation and clinical assessment.

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RESUMO

Cryptococcus neoformans são leveduras que acometem principalmente indivíduos imunocomprometidos, podendo causar a meningoencefalite dependendo do estado imunológico do hospedeiro. Os tratamentos convencionais têm enfrentado grandes desafios. Dessa forma, o objetivo desse estudo foi avaliar os efeitos antifúngicos dos fármacos cloridrato de verapamil (CV), cloridrato de fluoxetina (CF) e cloridrato de paroxetina (CP) isolados e combinados com anfotericina B (AmB) contra C. neoformans. Foram determinados os valores de Concentração Inibitória Mínima (CIM) e Concentração Fungicida Mínima (CFM) de acordo com a técnica de microdiluição em caldo proposta pelo Comitê Europeu de Teste de Susceptibilidade Antimicrobiana (EUCAST). Posteriormente, foi avaliada a atividade sinérgica dos fármacos combinados com AmB (EUCAST). Os efeitos das CIMs e das concentrações sinérgicas selecionadas foram avaliados em biofilmes, quantificando a biomassa por cristal violeta e sua viabilidade por contagem de colônias (UFC/mL). Além disso, foram analisados os efeitos dos mesmos na cápsula induzida desta levedura. Os ensaios in vivo foram realizados em Galleria mellonella avaliando a toxicidade dos compostos e a eficácia por análise de curva de sobrevivência e também o efeito em concentração de hemócitos. Os fármacos CV, CF e CP apresentaram valores de CIM de 113, 9,6 e 41µg/mL, respectivamente, e quando combinados com AmB resultaram em vinte concentrações sinérgicas, e uma concentração de cada combinação foi eleita para os ensaios seguintes. CV reduziu a biomassa do biofilme em até 38%, já CF e CP reduziram a biomassa de 22-30% quando isolados, e as combinações reduziram até 35 % da biomassa. O CP diminuiu a viabilidade do biofilme em até 25 % e quando o CF e CP foram combinados com AmB a redução chegou a 11 %. Além disso, todos os fármacos isolados e combinados reduziram o tamanho da cápsula da levedura, de 48-72 %. Em G. mellonella os fármacos não apresentaram toxicidade, eficácia ou ação na concentração de hemócitos. Assim, os fármacos avaliados apresentaram potencial antifúngico frente C. neoformans em todos os ensaios in vitro, podendo ser considerados novas alternativas para o tratamento destes patógenos(AU)

Cryptococcus neoformans are yeasts that mainly affect immunocompromised individuals, and may cause meningoencephalitis depending on the immunological state of the host. Conventional treatments have faced major challenges. Verapamil hydrochloride (CV), fluoxetine hydrochloride (CF) and paroxetine hydrochloride (CP) were isolated and combined with amphotericin B (AmB) against C. neoformans. Minimum Inhibitory Concentration (MIC) and minimum Fungicidal Concentration (CFM) values were determined according to the broth microdilution technique proposed by the European Committee for Antimicrobial Susceptibility Testing (EUCAST). Subsequently, the synergistic activity of drugs combined with AmB (EUCAST) was evaluated. The effects of MICs and selected synergistic concentrations were evaluated in biofilms, quantifying the biomass by violet crystal and its viability by colony-forming unit analysis (CFU / mL). In addition, the effects of the same in the induced capsule of this yeast were evaluated. In vivo assays were performed in Galleria mellonella evaluating the toxicity of the compounds and the efficacy by analysis of survival curve and also the effect on hemocyte concentration. The CV, CF and CP drugs had MIC values of 113, 9.6 and 41 µg / mL, respectively, and when combined with AmB resulted in twenty synergistic concentrations, and a concentration of each combination was chosen for the following trials. CV reduced biofilm biomass to 38%, while CF and CP reduced biomass to 22-30% when isolated, and combinations reduced to 35% of biomass. CP decreased biofilm viability to 25% and when CF and CP were combined with AmB the reduction reached to 11%. In addition, all drugs isolated and combined reduced the size of the yeast capsule to 48-72%. In G. mellonella the drugs did not present toxicity, efficacy or action in the concentration of hemocytes. We suggest that the liposolubility of the compounds has been a limiting factor in vivo analyzes. Thus, the evaluated drugs presented antifungal potential against C. neoformans in all in vitro assays, and could be considered new alternatives for the treatment of these pathogens(AU)

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