Halogenated Spirotetronates from <i>Actinoallomurus</i>

Two new members of the spirotetronate class, nai414-A and nai414-B, were discovered and isolated from an <i>Actinoallomurus</i> sp. Their structures were established by 1D and 2D NMR, UV, and MS analyses and by chemical degradation. They showed antimicrobial and antitumor activity against Gram-positive bacteria and against human microvascular endothelial cells, respectively. Substituting bromide for chloride ions in the growth medium afforded mono- and dibrominated derivatives

Accepting the Invitation to Open Innovation in Malaria Drug Discovery: Synthesis, Biological Evaluation, and Investigation on the Structure–Activity Relationships of Benzo[<i>b</i>]thiophene-2-carboxamides as Antimalarial Agents

Malaria eradication is a global health priority, but current therapies are not always suitable for providing a radical cure. Artemisinin has paved the way for the current malaria treatment, the so-called Artemisinin-based Combination Therapy (ACT). However, with the detection of resistance to ACT, innovative compounds active against multiple parasite species and at multiple life stages are needed. GlaxoSmithKline has recently disclosed the results of a phenotypic screening of an internal library, publishing a collection of 400 antimalarial chemotypes, termed the “Malaria Box”. After analysis of the data set, we have carried out a medicinal chemistry campaign in order to define the structure–activity relationships for one of the released compounds, which embodies a benzothiophene-2-carboxamide core. Thirty-five compounds were prepared, and a description of the structural features responsible for the in vitro activity against different strains of P. falciparum, the toxicity, and the metabolic stability is herein reported

Bioactive compounds of <i>Crocus sativus</i> L. and their semi-synthetic derivatives as promising anti-<i>Helicobacter pylori</i>, anti-malarial and anti-leishmanial agents

<div><p></p><p><i>Crocus sativus</i> L. is known in herbal medicine for the various pharmacological effects of its components, but no data are found in literature about its biological properties toward <i>Helicobacter pylori, Plasmodium</i> spp<i>.</i> and <i>Leishmania</i> spp. In this work, the potential anti-bacterial and anti-parasitic effects of crocin and safranal, two important bioactive components in <i>C. sativus</i>, were explored, and also some semi-synthetic derivatives of safranal were tested in order to establish which modifications in the chemical structure could improve the biological activity. According to our promising results, we virtually screened our compounds by means of molecular modeling studies against the main <i>H. pylori</i> enzymes in order to unravel their putative mechanism of action.</p></div

Optimization of 4‑Aminoquinoline/Clotrimazole-Based Hybrid Antimalarials: Further Structure–Activity Relationships, in Vivo Studies, and Preliminary Toxicity Profiling

Despite recent progress in the fight against malaria, the emergence and spread of drug-resistant parasites remains a serious obstacle to the treatment of infections. We recently reported the development of a novel antimalarial drug that combines the 4-aminoquinoline pharmacophore of chloroquine with that of clotrimazole-based antimalarials. Here we describe the optimization of this class of hybrid drug through in-depth structure–activity relationship studies. Antiplasmodial properties and mode of action were characterized in vitro and in vivo, and interactions with the parasite’s 'chloroquine resistance transporter' were investigated in a <i>Xenopus laevis</i> oocyte expression system. These tests indicated that piperazine derivatives <b>4b</b> and <b>4d</b> may be suitable for coadministration with chloroquine against chloroquine-resistant parasites. The potential for metabolism of the drugs by cytochrome P450 was determined in silico, and the lead compounds were tested for toxicity and mutagenicity. A preliminary pharmacokinetic analysis undertaken in mice indicated that compound <b>4b</b> has an optimal half-life

Metabolomic and chemogenomic profiling.

<p>(A) Metabolic profiling: Heat map showing metabolic fingerprints of 80 Malaria Box compounds and atovaquone control. Parasite extracts were analyzed by LC-MS, and changes in metabolite pools were calculated for drug-treated parasites as compared to untreated controls. Hierarchical clustering was performed on ²log-fold changes in metabolites (data in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.s003" target="_blank">S2 Table</a>), scaled from -3 to +3. Six of seven compounds (indicated in red) reported to target <i>Pf</i>ATP4 [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.ref025" target="_blank">25</a>] showed a distinct metabolic response characterized by the accumulation of dNTPs and a decrease in hemoglobin-derived peptides. A large cluster of compounds (indicated in blue) clustered with the atovaquone control (indicated in orange), and exhibit an atovaquone-like signature characterized by dysregulation of pyrimidine biosynthesis, and showed a distinct metabolic response characterized by the accumulation of dNTPs and a decrease in hemoglobin-derived peptides. (B) Chemogenomic profiling: A collection of 35 <i>P</i>. <i>falciparum</i> single insertion <i>piggyBac</i> mutants were profiled with 53 MMV compounds and 3 artemisinin (ART) compounds [Artesunate (AS), Artelinic acid (AL) and Artemether (AM)] for changes in IC₅₀ relative to the wild-type parent NF54 (data in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.s004" target="_blank">S3 Table</a>, genes queried in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.s005" target="_blank">S4 Table</a>). Clone PB58 carried a <i>piggyBac</i> insertion in the promoter region of the K13 gene and has an increased sensitivity to ART compounds as do PB54 and PB55 [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.ref033" target="_blank">33</a>]. Drug-drug relationships based on similarities in IC₅₀ deviations of compounds generated with <i>piggyBac</i> mutants created chemogenomic profiles used to define drug-drug relationships. The significance of similarity in MoA between Malaria Box compounds and ART was evaluated by Pearson’s correlation calculations from pairwise comparisons. The X axis shows the chemogenomic profile correlation between a Malaria Box compound and AS, the Y axis with AM; the color gradient indicates the average correlation with all ART derivatives tested. Five Malaria Box compounds (MMV006087, MMV006427, MMV020492, MMV665876, MMV396797) were identified as having similar drug-drug chemogenomic profiles to the ART sensitivity cluster.</p

Antiprotozoal Malaria Box compounds with activity in biological assays and lacking toxicity at therapeutic levels.

<p>Selectivity Index, SI, is toxicity level/activity level; p, probe-like; d, drug-like.</p

Malaria Box Heatmap.

<p>Shown are selected data from the HeatMap (<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005763#ppat.1005763.s002" target="_blank">S1 Table</a>) for the 400 Malaria Box compounds. Each column represents an assay (grouped by category), compounds are represented in rows. The red-green gradient represents higher to lower activity. Favorable PK activities are scored green. <i>Pf</i>: <i>Plasmodium falciparum</i>, <i>Pb</i>: <i>Plasmodium berghei</i>, PK: pharmacokinetics, sol.: solubility, hERG: human ether-a-go-go channel inhibition, DDI: drug-drug interactions (predicted).</p