In vitro susceptibility of Plasmodium falciparum Welch field isolates to infusions prepared from Artemisia annua L. cultivated in the Brazilian Amazon

Artemisinin is the active antimalarial compound obtained from the leaves of Artemisia annua L. Artemisinin, and its semi-synthetic derivatives, are the main drugs used to treat multi-drug-resistant Plasmodium falciparum (one of the human malaria parasite species). The in vitro susceptibility of P. falciparum K1 and 3d7 strains and field isolates from the state of Amazonas, Brazil, to A. annua infusions (5 g dry leaves in 1 L of boiling water) and the drug standards chloroquine, quinine and artemisinin were evaluated. The A. annua used was cultivated in three Amazon ecosystems (várzea, terra preta de índio and terra firme) and in the city of Paulínia, state of São Paulo, Brazil. Artemisinin levels in the A. annua leaves used were 0.90-1.13% (m/m). The concentration of artemisinin in the infusions was 40-46 mg/L. Field P. falciparum isolates were resistant to chloroquine and sensitive to quinine and artemisinin. The average 50% inhibition concentration values for A. annua infusions against field isolates were 0.11-0.14 μL/mL (these infusions exhibited artemisinin concentrations of 4.7-5.6 ng/mL) and were active in vitro against P. falciparum due to their artemisinin concentration. No synergistic effect was observed for artemisinin in the infusions

Efficient synthesis of a new aminoazasugar and dihydroxyprolines from an endocyclic enecarbamate

A novel procedure for the synthesis of trans-2,3-(2-aminomethyl)-cis-3,4-dihydroxypyrrolidine (a new aminoazasugar) and cis-2,3- and trans-2,3-cis-3,4-dihydroxyprolines is presented. Starting from the known endocyclic enecarbamate 1-carbobenzyloxy-2-pyrroline, the above compounds were efficiently synthesized in 6 or 7 steps in good overall yields. In the key step, trans-2,3-(1-carbobenzyloxy)-cis-3,4-diacetyloxy-2-methoxypyrrolidine underwent Lewis acid promoted cyanation, presumably via the corresponding N-acyliminium ion.45122321232

In vitro and in vivo antimalarial activity and cytotoxicity of extracts, fractions and a substance isolated from the Amazonian plant Tachia grandiflora (Gentianaceae)

Tachia sp. are used as antimalarials in the Amazon Region and in vivo antimalarial activity of a Tachia sp. has been previously reported. Tachia grandiflora Maguire and Weaver is an Amazonian antimalarial plant and herein its cytotoxicity and antimalarial activity were investigated. Spectral analysis of the tetraoxygenated xanthone decussatin and the iridoid aglyone amplexine isolated, respectively, from the chloroform fractions of root methanol and leaf ethanol extracts was performed. In vitro inhibition of the growth of Plasmodium falciparum Welch was evaluated using optical microscopy on blood smears. Crude extracts of leaves and roots were inactive in vitro. However, chloroform fractions of the root and leaf extracts [half-maximal inhibitory concentration (IC50) = 10.5 and 35.8 µg/mL, respectively] and amplexine (IC50= 7.1 µg/mL) were active in vitro. Extracts and fractions were not toxic to type MRC-5 human fibroblasts (IC50> 50 µg/mL). Water extracts of the roots of T. grandiflora administered by mouth were the most active extracts in the Peters 4-day suppression test in Plasmodium berghei-infected mice. At 500 mg/kg/day, these extracts exhibited 45-59% inhibition five to seven days after infection. T. grandiflora infusions, fractions and isolated substance have potential as antimalarials

Antiplasmodial activity of synthetic ellipticine derivatives and an isolated analog

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ellipticine has been shown previously to exhibit excellent in vitro antiplasmodial activity and in vivo antimalarial properties that are comparable to those of the control drug chloroquine in a mouse malaria model. Ellipticine derivatives and analogs exhibit antimalarial potential however only a few have been studied to date. Herein, ellipticine and a structural analog were isolated from Aspidosperma vargasii bark. A-ring brominated and nitrated ellipticine derivatives exhibit good in vitro inhibition of Plasmodium falciparum K1 and 3D7 strains. Several of the compounds were found not to be toxic to human fetal lung fibroblasts. 9-Nitroellipticine (IC50 = 0.55 mu M) exhibits greater antiplasmodial activity than ellipticine. These results are further evidence of the antimalarial potential of ellipticine derivatives. (C) 2014 Elsevier Ltd. All rights reserved.241226312634Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)National Malaria Network, Bionorth NetworkAmazonas State Foundation for the Advancement of Research (FAPEAM/PRONEX)European Community FP7-Marie Curie Actions-People-International Research Staff Exchange Scheme (IRSES)PIRSES-GA-2011-295262Academy of Finland and Magnus Ehrnrooth FoundationConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq