Antibacterial activity of chalcones, hydrazones and oxadiazoles against methicillin-resistant Staphylococcus aureus
摘要:
The increase in antibiotic resistance due to multiple factors has encouraged the search for new compounds which are active against multidrug-resistant pathogens. In this context, chalcones, dihydrochalcones, hydrazones and oxadiazoles were tested against Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus (MRSA) isolates, which were obtained from clinical laboratories and were characterized as MRSA using traditional and molecular methods. Among 65 tested compounds, two chalcones, one dihydrochalcone and two hydrazones were active against MRSA. Based on the minimal inhibitory concentration and cytotoxicity, hydrazones provided a better selectivity index than chalcones. Active hydrazones are promising antibiotic-like substances and they should be the subject of further microbiological studies. (C) 2011 Elsevier Ltd. All rights reserved.
Synthetic compounds from an <i>in house</i> library as inhibitors of falcipain-2 from <i>Plasmodium falciparum</i>
作者:Jean Borges Bertoldo、Louise Domeneghini Chiaradia-Delatorre、Alessandra Mascarello、Paulo César Leal、Marlon Norberto Sechini Cordeiro、Ricardo José Nunes、Emir Salas Sarduy、Philip Jon Rosenthal、Hernán Terenzi
DOI:10.3109/14756366.2014.920839
日期:2015.3.4
Falcipain-2 (FP-2) is a key cysteine protease from the malaria parasite Plasmodium falciparum. Many previous studies have identified FP-2 inhibitors; however, none has yet met the criteria for an antimalarial drug candidate. In this work, we assayed an in-house library of non-peptidic organic compounds, including (E)-chalcones, (E)-N'-benzylidene-benzohydrazides and alkylesters of gallic acid, and assessed the activity toward FP-2 and their mechanisms of inhibition. The (E)-chalcones 48, 54 and 66 showed the lowest IC50 values (8.5 +/- 0.8 mu M, 9.5 +/- 0.2 mu M and 4.9 +/- 1.3 mu M, respectively). The best inhibitor (compound 66) demonstrated non-competitive inhibition, and using mass spectrometry and fluorescence spectroscopy assays, we suggest a potential allosteric site for the interaction of this compound, located between the catalytic site and the hemoglobin binding arm in FP-2. We combined structural biology tools and mass spectrometry to characterize the inhibition mechanisms of novel compounds targeting FP-2.