RESUMO
Further investigations of the VLC (vacuum-liquid chromatography) fractions obtained from the dichloromethane solubles of the tropical marine sponge Cymbastela hooperi led to the isolation and characterization of five new diterpene formamides, 1-5. Compound 1 is one of the very few examples of a natural product that contains both formamide and isonitrile functionalities within the same molecule. In in vitro antiplasmodial bioassays, 1 was found to have moderate activity (IC(50) 0.5 microg/mL), 2 had weak activity (IC(50) 14.8 microg/mL), and 3-5 were inactive. The pattern of activity found for the metabolites investigated in the current study is consistent with previous findings for these classes of molecules.
Assuntos
Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Formamidas/isolamento & purificação , Formamidas/farmacologia , Poríferos/química , Animais , Antimaláricos/química , Diterpenos/química , Ensaios de Seleção de Medicamentos Antitumorais , Formamidas/química , Humanos , Concentração Inibidora 50 , Células KB , Biologia Marinha , Estrutura Molecular , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , EstereoisomerismoRESUMO
Ribosomal subunit protein 9 (rps9) is a nuclearly encoded protein that resides in the apicoplast organelle of Toxoplasma gondii. Two cis-acting regions within the rps9 transit domain (amino acids 38-49 and 79-86), when combined with the rps9 signal sequence, were necessary and sufficient for apicoplast targeting. To investigate proteins interacting with the rps9 leader sequence, parasites expressing rps9 leader constructs fused to a glutathione S-transferase (GST) reporter were prepared, and proteins associated with the leader constructs were purified from extracts by affinity chromatography. In addition to GST-containing peptides, proteins with apparent masses of 92, 90, 86, and 160 kDa were purified. Mass spectrometry data suggested that the 92- and 90-kDa polypeptides appear to be subtilisin-like proteins, whereas the 86-kDa polypeptide was identified as the molecular chaperone BiP of T. gondii.
Assuntos
Proteínas Fúngicas , Proteínas de Choque Térmico , Organelas/química , Proteínas Ribossômicas/química , Toxoplasma/fisiologia , Sequência de Aminoácidos , Animais , Western Blotting , Proteínas de Transporte/análise , Proteínas de Transporte/química , Células Cultivadas , Chlorocebus aethiops , Cromatografia de Afinidade , Chaperona BiP do Retículo Endoplasmático , Fibroblastos/parasitologia , Glutationa Transferase/genética , Glutationa Transferase/fisiologia , Proteínas de Fluorescência Verde , Humanos , Indicadores e Reagentes/química , Proteínas Luminescentes/química , Espectrometria de Massas , Chaperonas Moleculares/análise , Chaperonas Moleculares/química , Dados de Sequência Molecular , Mapeamento de Peptídeos , Sinais Direcionadores de Proteínas/fisiologia , Proteínas Ribossômicas/genética , Toxoplasma/genética , Toxoplasma/ultraestrutura , Transfecção , Células Vero/parasitologiaRESUMO
Antiplasmodial and cytotoxicity testing of five highly oxygenated natural products (6R,12R,14R-colletoketol, 6R,11R,12R,14R-colletoketodiol, dihydrobotrydial, pycnidione, and 3R,4S-hydroxymellein), all derived from fungi of marine origin, showed one of them, pycnidione, to have activities against three different strains of Plasmodium falciparum in the sub-micromolar (microM) range. Although the mean selectivity index of 1 for the observed antiplasmodial activity of 4 is low, pycnidione's usefulness as a potential lead structure should not be ignored.