Currently, the pharmaceutical industry devotes great attention to drug degradation products because these compounds can offer risks to patients. A previous degradation study of betahistine (N-α-methyl-2-pyridylethylamine) conducted under different stress conditions detected three main impurities named A, B and C. Degradation products were analyzed by high-resolution mass spectrometry in electrospray source and time of flight analyzer (ESI-TOF) and nuclear magnetic resonance (NMR). Impurity mutagenicity was evaluated by Derek Nexus and Sarah Nexus softwares. Liquid chromatography hyphenate with tandem mass spectrometry (LC-MS/MS) analysis of the betahistine forced degradation sample indicated the presence of a new impurity, which was named impurity C1. 2D NMR experiments allowed the complete structural characterization of the new entity. The active pharmaceutical ingredient and degradation impurities were classified as inactive in the in silico mutagenic studies. Systematic investigation of a forced degradation sample led to the characterization of a new betahistine impurity. The in silico mutagenicity study of the betahistine degradation impurities may be useful in the risk assessment of the drug products.

Thiosemicarbazones are a class of compounds of interest for Medicinal Chemistry, as they are structurally diverse and have numerous biological activities reported in the literature. This study describes the synthesis of seventeen thiosemicarbazones, which were investigated as potential therapeutic agents for the treatment of Alzheimer's disease through antioxidant tests and an inhibitory assay of the acetylcholinesterase enzyme. All compounds showed excellent inhibition of acetylcholinesterase and exhibited excellent antioxidant action when compared to the standards. In addition, a quantum study was carried out, in which the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy values of each compound were obtained. From these theoretical data, chemical properties were calculated and correlated with the experimental data.

Uma forma alterada da proteína prion celular, a PrPSc ou PrPRes, está envolvida na ocorrência das encefalopatias espongiformes transmissíveis. Nós sintetizamos e caracterizamos previamente compostos aromáticos que inibem o acúmulo da proteína prion resistente a proteases (PrPRes) em células infectadas com prion scrapie. Estes compostos pertencem a diferentes classes químicas, incluindo acilhidrazonas, chalconas e oxadiazóis. Alguns dos compostos ativos não apresentaram toxicidade para células de neuroblastoma em cultura e parecem apresentar propriedades de fármacos, uma vez que todos obedecem aos 5 quesitos da regra de Lipinski e apresentam perfil farmacocinético desejável, como predito in silico. Antes de avaliar a eficácia in vivodos compostos aromáticos em camundongos infectados com prion scrapie, é necessário estimar sua segurança em camundongos saudáveis. Neste trabalho nós utilizamos camundongos Suíços para avaliar o perfil de toxicidade aguda dos seis compostos mais promissores, as 2,4,5-trimetoxichalconas (J1, J8, J20 e J35) e os 1,3,4-oxadiazóis (Y13 e Y17). Administração oral em dose única (300 mg/kg) de J1, J8, J20, J35, Y13 e Y17 ou administração repetida via intraperitoneal (10 mg/kg, 3 vezes por semana, por 4 semanas) de J1, J8 e J35, não geraram toxicidade nos camundongos. Nós acreditamos fortemente que as trimetoxichalconas e os oxadiazóis investigados são compostos interessantes para serem futuramente avaliados in vivo contra as doenças causadas por prions.

An altered form of the cellular prion protein, the PrPScor PrPRes, is implicated in the occurrence of the still untreatable transmissible spongiform encephalopathies. We have previously synthesized and characterized aromatic compounds that inhibit protease-resistant prion protein (PrPRes) accumulation in scrapie-infected cells. These compounds belong to different chemical classes, including acylhydrazones, chalcones and oxadiazoles. Some of the active compounds were non-toxic to neuroblastoma cells in culture and seem to possess drugable properties, since they are in agreement with the Lipinski´s rule of 5 and present desirable pharmacokinetic profiles as predicted in silico. Before the evaluation of the in vivo efficacy of the aromatic compounds in scrapie-infected mice, safety assessment in healthy mice is needed. Here we used Swiss mice to evaluate the acute toxicity profile of the six most promising anti-prionic compounds, the 2,4,5-trimethoxychalcones (J1, J8, J20 and J35) and the 1,3,4-oxadiazoles (Y13 and Y17). One single oral administration (300 mg/kg) of J1, J8, J20, J35, Y13 and Y17 or repeated intraperitoneal administration (10 mg/kg, 3 times a week, for 4 weeks) of J1, J8 and J35, did not elicit toxicity in mice. We strongly believe that the investigated trimethoxychalcones and oxadiazoles are interesting compounds to be further analyzed in vivo against prion diseases.

A doença de Chagas, uma infecção parasitária amplamente distribuída na América Latina, é um problema grave de saúde pública com conseqüências devastadoras em termos de morbidade e mortalidade humana. A enzima cruzaína é a principal cisteíno protease do Trypanosoma cruzi, agente etiológico da tripanossomíase Americana ou doença de Chagas, e foi selecionada como alvo atrativo para o desenvolvimento de novos fármacos tripanocidas. No presente trabalho, a síntese e os efeitos inibitórios de uma série de trinta e três chalconas e sete hidrazidas são descritos contra a enzima cruzaína de T.cruzi. A maioria dos compostos mostraram inibição promissora in vitro (valores de IC50 na faixa de 20-60 μM), o que sugere o potencial desses compostos como candidatos a líderes para contínuo desenvolvimento. Doze compostos são inéditos, sendo que quatro destes (7, 13, 16 e 18) estão entre os inibidores mais potentes da série.

Chagas' disease, a parasitic infection widely distributed throughout Latin America, is a major public health problem with devastating consequences in terms of human morbidity and mortality. The enzyme cruzain is the major cysteine protease from Trypanosoma cruzi, the etiologic agent of American trypanosomiasis or Chagas' disease, and has been selected as an attractive target for the development of novel trypanocidal drugs. In the present work, we describe the synthesis and inhibitory effects of a series of thirty-three chalcone and seven hydrazide derivatives against the enzyme cruzain from T. cruzi. Most of the compounds showed promising in vitro inhibition (IC50 values in the range of 20-60 μM), which suggest the potential of these compounds as lead candidates for further development. Twelve compounds have not been reported before, and four of them (7, 13, 16 e 18) are among the most potent inhibitors of the series.