A microplate assay and a thin-layer chromatography (TLC) "in situ" assay based on the Ellman assay was used to screen for acetylcholinesterase inhibitors from ethyl acetate and methanol extracts of Brazilian medicinal plants of families that, according to the literature, have traditional uses that might be connected with acetylcholinesterase inhibition. Eighteen species belonging to Convolvulaceae, Crassulaceae, Euphorbiaceae, Leguminosae, Malvaceae, Moraceae, Nyctaginaceae and Rutaceae families were tested. The most active plants were Ipomoea asarifolia (IC 50 = 0.12 mg/mL), Jatropha curcas (IC 50 = 0.25 mg/mL), Jatropha gossypiifolia (IC 50 = 0.05 mg/mL), Kalanchoe brasiliensis (IC 50 = 0.16 mg/mL) and Senna alata (IC 50 = 0.08 mg/mL). The most promising extracts were the Jatropha gossypiifolia and Senna alata species assuming there were compounds with a similar activity to galanthamine, which should contain about 1% of an active compound, or if present at lower levels even more active compounds than galanthamine (IC 50 = 0.37 x 10 -3 mg/ mL) should be present.Keywords: Brazilian medicinal plants, Alzheimer's disease, acetylcholinesterase inhibitors, microplate assay. Plantas medicinais brasileiras promissoras para inibição da acetilcolinesterase ResumoOs ensaios de microplaca e cromatografia em camada delgada com base no ensaio de Ellman foram usados para triagem de inibidores da acetilcolinesterase dos extratos acetato de etila e metanol de plantas medicinais brasileiras de famílias que, segundo a literatura, tem usos tradicionais que podem estar relacionadas com a inibição da acetilcolinesterase, enzima associada ao mal de Alzheimer. Dezoito plantas das famílias: Convolvulaceae, Crassulaceae, Euphorbiaceae, Leguminosae, Malvaceae, Moraceae, Nyctaginaceae e Rutaceae foram testadas. As espécies mais ativas foram Ipomoea asarifolia (CI 50 = 0,12 mg/mL), Jatropha curcas (CI 50 = 0,25 mg/mL), Jatropha gossypiifolia (CI 50 = 0,05 mg/mL), Kalanchoe brasiliensis (CI 50 = 0,16 mg/mL) e Senna alata (CI 50 = 0,08 mg/mL). Os extratos mais promissores foram os das espécies Jatropha gossypiifolia e Senna alata, assumindo a presença de compostos com atividade semelhante à galantamina que deve conter cerca de 1% de um composto ativo, ou se presentes em menores níveis ainda mais compostos ativos que a galantamina (CI 50 = 0,37 x10 -3 mg/mL) devem estar presentes.Palavras-chave: plantas medicinais brasileiras, doença de Alzheimer, inibidores da acetilcolinesterase, microplaca.

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ABSTRACT. The cashew tree (Anacardium occidentale) represents one of the major cheapest sources of non-isoprenoid phenolic lipids, which have a variety of biological properties: they can act as molluscicides, insecticides, fungicides, have anti-termite properties, have medicinal applications, and demonstrate antioxidant activity in vitro. Immature cashew nut-shell liquid (iCNSL) is a unique natural source of unsaturated long-chain phenols. Their use has stimulated much research in order to prepare drug analogues for application in several fields. The objective of the present study was to determine whether iCNSL has antioxidant properties when used in strains of the yeast Saccharomyces cerevisiae and to measure the inhibitory activity of acetylcholinesterase. The constituents were identified using thin-layer chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and 1 H and 13 C nuclear magnetic resonance. The iCNSL contains anacardic acid, cardanol, cardol, and 2-methyl cardol. Immature cashew nut oil contains triacylglycerols, fatty acids, alkyl-substituted phenols, and cholesterol. The main constituents of the free fatty acids are palmitic (C 16:0 ) and oleic acid (C 18:1 ). iCNSL has excellent protective activities in strains of S. cerevisiae against oxidative damage induced by hydrogen peroxide and inhibits acetylcholinesterase activity. iCNSL may have an important role in protecting DNA against damage induced by reactive oxygen species, as well as hydrogen peroxide, generated by intra-and extracellular mechanisms.

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Abstract:The central nervous system (CNS) depressant and anticonvulsant activities of Citrus limon (L.) Osbeck, Rutaceae, essential oil (EO) were investigated in animal models. The EO (50, 100 and 150 mg/kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity of animals when compared with the control group, up to thirty days after the administration and the dose of 150 mg/kg significantly reduced the remaining time of the animals on the Rota-rod apparatus. Additionally, C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by pentylenetetrazole (PTZ). The administration of FLU (10 mg/kg, i.p.), GABA A -benzodiazepine (GABA-BZD) receptor antagonist, antagonized the effect of C. limon essential oil at higher dose. This C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by picrotoxin (PIC) at higher dose. In the same way, the anticonvulsant effect of the EO was affected by pretreatment with flumazenil, a selective antagonist of benzodiazepine site of GABA A receptor. These results suggest a possible CNS depressant and anticonvulsant activities in mice that needs further investigation.

Oxidative stress is a major mechanism underlying the development of various neurodegenerative diseases (Alzheimer, Parkinson, Huntington and amyotrophic lateral sclerosis). Excessive formation of reactive oxygen species (ROS) and nitrogen (RNSs) can overburden the ability of the enzymatic antioxidant defense mechanisms (superoxide dismutase, catalase and glutathione reductase) and non-enzymatic (uric acid, ascorbic acid, α-tocopherol and reduced glutathione), causing the development of oxidative stress, and consequently, impairing the neuronal system cells by means of oxidative damage to a variety of important biological molecules such as lipids, DNA and proteins. Considering the importance of oxidative stress in neurodegenerative diseases, the present review aims to address the main parameters evaluated in in vitro studies on oxidative stress in different models of neurodegenerative diseases.The literary review was conducted through Pubmed, Science Direct, LILACS, Scielo and Google using following keywords: oxidative stress, neurodegenerative diseases and parameters of oxidative stress. We selected articles published between 2002 and 2017.The in vitro evaluation of the oxidative stress related parameters has provided a preliminary view about the pathogenesis of many neurodegenerative diseases (Alzheimer's, Parkinson's, Huntington's and Amyotrophic lateral sclerosis). In this way, it has demonstrated the mechanism of action of ROS/RNSs in these diseases by direct or indirect detection through several experimental procedures in vitro.

PHY exerted antioxidant potential in our current non- and preclinical test systems and can be a good candidate for the development of treatments of oxidative stress mediated diseases.

The study of natural substances has increased in recent years in the search for compounds with pharmacological properties that can be used for the development of new drugs. The alkaloids, substances extracted natural sources, show promising pharmacological activities, including pharmacological activities for the treatment of neurodegenerative diseases such as Alzheimer's disease, whose treatment is based on the use of various drugs. Thus, the article aims to a technological prospecting of alkaloids that presented important properties in the treatment of neurodegenerative diseases, namely, antioxidant, anxiolytic, anti-inflammatory and antidepressant properties. A literature review was conducted in the databases PubMed, Science Direct, Scopus, Scielo and Google Academics using the following key words: alkaloids, pharmacology, neurodegenerative diseases, cholinesterase inhibitors, antidepressants, anti-inflammatories, antioxidant and anxiolytic. Articles, dissertations and theses published between 2003 and 2015 were selected. Several studies showed through in vitro of in vitro and/or in vivo methods that many alkaloids extracted from plants showed anticholinesterase, antioxidant, anxiolytic, anti-inflammatory and antidepressant properties in the treatment of symptoms and progression of certain diseases such as Alzheimer's disease.