resumo
Solid 1:1 inclusion compounds of triclosan with native and permethylated 6-cyclodextrin (beta-CD and TRIMEB) were prepared by co-crystallisation and co-evaporation, respectively, and studied by FT-IR and C-13{H-1} CP/MAS NMR spectroscopies, thermogravimetric analysis, X-ray diffraction and theoretical calculations. Results showed that triclosan inclusion into TRIMEB afforded an amorphous solid, whilst beta-CD triclosan is composed of microcrystals belonging to two different phases. In the phase featuring larger crystals, X-ray diffraction was carried out and the beta-CD host units, packing head-to-head in infinite channels, were refined; the geometry for the included but highly disordered triclosan molecules was assessed by theoretical calculations. The bacterial growth inhibitory action of the inclusion compounds was studied in comparison to that of pure triclosan on Gram-negative (Salmonella, Escherichia) and Gram-positive strains (Bacillus, Listeria, Enterococcus and Staphylococcus) typically associated with human pathologies, and also on environmental bacteria isolated from different soil and water sources. The antimicrobial activities obtained in the present work showed that, of the two CD hosts, TRIMEB brings the most favourable carrier effect: it reduced the toxicity of triclosan against some of the environmental strains and afforded slightly higher action against virulent strains. (C) 2013 Elsevier B.V. All rights reserved.
palavras-chave
MOLYBDENOCENE DICHLORIDE CP2MOCL2; CAMBRIDGE STRUCTURAL DATABASE; C-13 CHEMICAL-SHIFTS; ENOYL-ACP REDUCTASE; SOLID-STATE; PLASMODIUM-FALCIPARUM; CRYSTAL-STRUCTURES; COMPLEXES; CHEMISTRY; POLYMERS
categoria
Chemistry; Pharmacology & Pharmacy
autores
Ramos, AI; Braga, TM; Fernandes, JA; Silva, P; Ribeiro-Claro, PJ; Paz, FAA; Lopes, MFS; Braga, SS
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
José Alberto Pires Fernandes
Bolseiro de pós-Doutoramento
Paulo Ribeiro-Claro
Professor Associado com Agregação
Susana Isabel Fonseca de Almeida Santos Braga
Investigadoragradecimentos
We acknowledge Fundacao para a Ciencia e a Tecnologia (FCT), OE and FEDER through the programme COMPETE, for general funding to QOPNA (PEst C/QUI/UI0062/2011) and CICECO (PEst C/CTM/LA0011/2011), and for specific funding towards the purchase of the single-crystal X-ray diffractometer. The FCT and the European Social Fund are acknowledged for grants SFRH/BD/41882/2007 (to TMB), SFRH/BPD/63736/2009 (to JAF), SFRH/BPD/78020/2011 (to SSB) and SFRH/BD/46601/2008 (to PS). We thank CICECO for granting access to the Flamingo computer cluster.