Evaluation of Antiplasmodial activity of extracts and constituents from Ampelozizyphus amazonicus

PMID: 26664012 WOS: 000362879000003BACKGROUND: Ampelozizyphus amazonicus Ducke, a plant that is widely used by the population of the Amazonian region to prevent and treat malaria, was investigated in this work, which describes, for the first time, the antiplasmodial activity of its extracts and associates this activity with its isolated constituents. METHODS: Different extracts with solvents of increasing polarity (hexane, chloroform, ethanol, and water) were obtained of the root bark. This procedure resulted in extracts that were characterized for their constituents. The cytotoxicity and activity of the extracts against Plasmodium berghei (schizontocidal activity, liver stage) and Plasmodium falciparum (3D7 and Dd2 strains, erythrocyte stage) were assessed in vitro. RESULTS: Of the four extracts assayed against P. berghei, the chloroform extract showed the greatest activity, with an inhibitory concentration 50% (IC50) value of 30.1 µg/mL, followed by the aqueous extract (IC50 = 39.9 µg/mL). The chloroform extract exhibited the highest antiplasmodial activity in the erythrocyte stage of P. falciparum, with an IC50 value lower than 15 µg/mL. Fractionation of this more active extract led to the isolation and elucidation of pentacyclic triterpenes, lupeol, betulin and betulinic acid, which showed antiplasmodial activities with IC50 values ranging from 5.6 to 80.30 µM. The most active of these, betulinic acid, was further quantified in the extracts by high-performance liquid chromatography-photodiode array detector analyzes. The higher amount was found in the chloroform extract, which was the most active one against P. falciparum. CONCLUSION: The results obtained in this work may partly explain the popular intake of A. amazonicusas an antimalarial remedy in the Amazon region.publishersversionpublishe

Avaliação teórica e experimental da atividade anticorrosiva de enaminoésteres frente ao aço-carbono em meio ácido/ Theoretical and experimental evaluation of the anticorrosive activity of enaminoesters against carbon steel in acid medium

Corrosão pode ser definida como a deterioração de materiais, geralmente metálicos, por ação física, química ou eletroquímica do meio. Dentre os diversos materiais que podem sofrer corrosão, o aço carbono é o mais utilizado na indústria. Enaminoésteres são compostos considerados potenciais inibidores de corrosão devido a presença de grupos acila, amino e ligação dupla. Neste trabalho, três enaminoésteres foram sintetizados, derivados da anilina, benzilamina e fenetilamina, e sua atividade anticorrosiva avaliada através de experimentos eletroquímicos: Polarização Potenciodinâmica (PP), Resistência à Polarização Linear (RPL) e Espectroscopia de Impedância Eletroquímica (EIE). Cálculos teóricos foram utilizados para calcular a energia do orbital de fronteira HOMO (EHOMO), LUMO (ELUMO), a diferença de energia entre os orbitais (?ELUMO-HOMO) e momento de dipolo (µ). O derivado da fenetilamina apresentou melhor eficiência de inibição da corrosão com 90 e 92% pelas técnicas de EIE e RPL, respectivamente, correlacionado com o estudo de modelagem molecular que mostrou o menor valor de ?ELUMO-HOMO e maior momento de dipolo

Study of the Development of the Puerto Rican Cultural Identity. (Spanish Text)

155 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1976.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Reações nucleofilicas dos cloretos imidoilas e - cloroximas

Orientador : Joseph MillerDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaMestrad

NMR Spectroscopy, Hammett Correlations and Biological Activity of Some Schiff Bases Derived from Piperonal

A series of eleven Schiff Bases have been synthesized. They were obtained by condensation of piperonal (3,4-methylenedioxybenzaldehyde) with the corresponding aromatic primary amines. Their ¹H and 13C-NMR spectra have been obtained and the Hammett correlations including chemical shifts and the subsitutent constants (sigmap, sigmaR e sigmaI) were studied. Linear and bilinear significant correlations were observed for iminic carbon (C-alpha) and C-1?, showing a more significant ressonance effect on chemical shifts. The chemical shifts for C-4? were highly affected by substituent effects, especially for halogens in the expected direction. Their biological activity against microorganisms has also been measured and significant activity was showed against Epidermophyton floccosum. The biological activity did not give a reasonable relationship with electronic effects