A potent and selective reaction hijacking inhibitor of Plasmodium falciparum tyrosine tRNA synthetase exhibits single dose oral efficacy in vivo.

The Plasmodium falciparum cytoplasmic tyrosine tRNA synthetase (PfTyrRS) is an attractive drug target that is susceptible to reaction-hijacking by AMP-mimicking nucleoside sulfamates. We previously identified an exemplar pyrazolopyrimidine ribose sulfamate, ML901, as a potent reaction hijacking inhibitor of PfTyrRS. Here we examined the stage specificity of action of ML901, showing very good activity against the schizont stage, but lower trophozoite stage activity.

Inhibitors of malaria parasite cyclic nucleotide phosphodiesterases block asexual blood-stage development and mosquito transmission.

Cyclic nucleotide-dependent phosphodiesterases (PDEs) play essential roles in regulating the malaria parasite life cycle, suggesting that they may be promising antimalarial drug targets. PDE inhibitors are used safely to treat a range of noninfectious human disorders. Here, we report three subseries of fast-acting and potent PDEβ inhibitors that block asexual blood-stage parasite development and that are also active against human clinical isolates.

Improved production of palitantin by design of experiments and semi-synthesis of palitantin derivatives for bioactivity assessment.

A new method for the production and isolation of (+)-palitantin (1) is herein reported, from cultures of the fungal strain Penicillium sp. AMF1a. (+)-Palitantin was isolated in 160 mg/L yield, as an alternative procedure to obtain 1 at a larger scale.

Structure and Biosynthesis of Perochalasins A-C, Open-Chain Merocytochalasans Produced by the Marine-Derived Fungus sp. M16.

Novel open-chain merocytochalasans, perochalasins A-C (-), containing an unusual N-O six-membered heterocyclic moiety, were isolated from cultures of the marine-derived sp. M16 fungus, along with cytochalasin Z (), cytochalasin Z (), [12]-cytochalasin (), and phenochalasin B (). The structures of compounds - were established by analysis of the spectroscopic data.

[1-7-NαC]-Crocaorb A1 and A2, orbitides from the latex of Croton campanulatus.

Two new heptapeptides, [1-7-NαC]-crocaorbs A1 (1) and A2 (2), were isolated from the latex of Croton campanulatus. Their structures were determined using NMR spectroscopic techniques, ESI-HRMS data, Marfey's method, and further refined using molecular dynamics with simulated annealing (MD/SA). Molecular dynamics calculations of peptides 1 and 2 demonstrated greater stability in simulations using a biological solvent compared to those using DMSO.