The pharmacotherapy for Alzheimer's disease (AD) includes the use of acetylcholinesterase inhibitors (AChEI). Recent investigations for novel AD therapeutic agents from plants suggested that Tabernaemontana genus is a promising source of novel anticholinesterasic indole alkaloids. In this work two fast screening techniques were combined in order to easily identify novel cholinesterase inhibitors (ChEI). Gas chromatography-mass spectrometry (GC-MS) of the less polar alkaloidic fractions obtained from the acid-base extraction of the stalk of T. laeta revealed thirteen monoindole alkaloids, four of them confirmed by co-injection with previously isolated alkaloids. The others were tentatively identified by mass fragmentation analysis. By gas chromatography with flame ionization detection (GC-FID) and using isatin as internal standard, affinisine and voachalotine were determined as major compounds. These fractions and fourteen previously isolated alkaloids, obtained from root bark of T. laeta and T. hystrix were investigated for acetyl (AChE) and butyrylcholinesterase (BuChE) inhibitory activities by the modified Ellman's method in thin layer chromatography (TLC-ChEI). Results showed selective inhibition of the alkaloids heyneanine and N b -methylvoachalotine for BuChE, and 19-epi-isovoacristine for AChE, whereas olivacine, affinisine, ibogamine, affinine, conodurine and hystrixnine inhibited both enzymes. In addition to confirming that monoterpenoid indole alkaloids can be novel therapeutic agents for AD, this is the first report of the ChEI activity of olivacine, a pyridocarbazole alkaloid.

Um novo alcalóide, denominado histrixnina (1), e cinco alcalóides indólicos conhecidos, ibogamina (2), olivacina (3) e affinina (4), affinisina (5) e N b -metilaffinisina (6), foram isolados do extrato metanólico das cascas das raízes de Tabernaemontana hystrix. Os triterpenos conhecidos 3-O-acetil-α-amirina, 3-O-acetil-β-amirina, 3-O-acetil-lupeol foram também identificados. As estruturas dos compostos foram elucidadas com base na análise de dados espectroscópicos.A new alkaloid, named hystrixnine (1), and five known indole alkaloids, ibogamine (2), olivacine (3), affinine (4), affinisine (5) and N b -methylaffinisine (6), were isolated from the root bark of Tabernaemontana hystrix. The known triterpenes α-amyrin acetate, β-amyrin acetate and lupeol acetate were also identified. The structures of the compounds were elucidated based on spectroscopic studies.

The chemistry teaching process is essential during children and teenagers learning process of the various concepts of science. However, sometimes, it is not successful because of the absence of practical experiments. For this reason, this paper aimed to build chemistry teaching materials using low cost products for high schools of João Monlevade city, state of Minas Gerais. These materials were produced aiming to create a new teaching concept through practical experiments easily executed and that could be presented in chemistry educational events in a funny and playful way. The purpose of these materials is to associate the theoretical knowledge present in class with the practice experience, checking if with the observation of an experiment it is possible to explain/understand the chemistry process involved in it. This project achieved its aim in a successful way for the teachers and the students. It confirmed that though a simple and didactic experimentation and the use of daily-life products can motivate scientific experiments.

This work shows the analysis of the corrosive effect on carbon steel and stainless steel in aqueous medium, in order to compare the damages caused to these metals through the contact with ions which are present in the environment, as well as to measure the price-performance ratio of the use of these materials, since the corrosion resistance is linked to the commercial value of these metals. For this purpose, the methodology used was the corrosion test in SAE 1015 carbon steel and ACE P399B stainless steel, which were exposed to diluted solutions of sodium chloride 0,1 mol.L-1, potassium bromide 0,1 mol.L-1 and one containing 50% sodium chloride and 50% potassium bromide 0,1 mol.L-1, then the variation of mass of each metal sample in these different environments as well as their respective corrosion rate were verified. The results showed that although stainless steel suffers corrotion, carbon steel is the most affected by the ions present in such environment. In addition, the sodium chloride solution proved to be the most harmful medium for both steels, which is due to the release of chloride ions in these metals. Seen in these terms, as expected, stainless steel is the most resistant material to corrosion. However, in comparative terms, it did not show an exorbitant difference in relation to carbon steel, and can, therefore, be substituted by it in certain situations, in which the price-performance ratio is demanded.

Catharanthus roseus (L) G. Don (Madagascar periwinkle) belongs to the Apocynaceace family and is widely spread throughout tropical and subtropical regions of the world. The plant produces several important alkaloids, such as ajmalicine and serpentine, which are used in the treatment of circulatory diseases. The potential of inoculation with arbuscular mycorrhizal fungi (AMF) and nitrogen fertilization to enhance the production of alkaloids was investigated in periwinkle. A greenhouse experiment was carried out to evaluate the effects of arbuscular mycorrhizal fungi and N fertilizer dosages on plant growth, production of ajmalicine, and nutrient content in roots. The concentration of ajmalicine was determined by reverse-phase high-performance liquid chromatography with UV detection. The experiment was designed in randomized blocks in a 4 × 4 factorial scheme with four microbiological treatments (control-without mycorrhiza; Claroideoglomus etunicatum; Rhizophagus intraradices; mixed inoculum-Rhizophagus clarus + Gigaspora margarita), and four N fertilizer dosages (15, 30, 60, and 120 mg kg-1) with four replications. Catharanthus roseus growth was higher when plants were inoculated with mixed inoculum (R. intraradices + G. margarita) and C. etunicatum. The mixed inoculum (R. intraradices + G. margarita) and C. etunicatum, combined with N fertilization, enhanced ajmalicine yield. Catharanthus roseus inoculated with mycorrhiza showed increased P absorption and reduced N content.