RESUMEN
A simple and efficient strategy is proposed to significantly improve the antibacterial activity of peptaibols and other antimicrobial peptides by N-terminal capping with 1,2,3-triazole bearing various hydrophobic substituents on C-4. Such N-terminal insertions on alamethicin F50/5 could enhance its antimicrobial activity on Gram-positive bacteria without modification of its overall three-dimensional structure. Although the native peptide and its analogues shared comparable helical contents, the crystal structure of one of the most active derivative showed a local slight distortion of the N-terminal extremity, which was also observed in solution using NMR spectroscopy. Importantly, fluorescence studies showed that the N-capped derivatives had increased affinity for liposomes, which may indicate they interacted more strongly with the bacterial membrane than alamethicin F50/5.
Asunto(s)
Alameticina/análogos & derivados , Antiinfecciosos/química , Triazoles/química , Alameticina/metabolismo , Alameticina/farmacología , Antiinfecciosos/metabolismo , Antiinfecciosos/farmacología , Dicroismo Circular , Química Clic , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Liposomas/química , Liposomas/metabolismo , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Peptaiboles/química , Peptaiboles/metabolismo , Peptaiboles/farmacologíaRESUMEN
Chemical composition and antifungal activity of essential oils of Algerian Mentha species were studied. Chemical compositions of different Mentha species oils (Mentha rotundifolia, M. spicata, M. pulegium, and M. piperita) were investigated by capillary GC and GC/MS, and their antifungal activities were evaluated by means of paper disc diffusion method and minimum inhibitory concentration (MIC) assays. In total, 98 components from all Mentha species were identified. All oils were rich in monoterpene-oxygenated components. In addition, we reported fumigant antifungal activity of Algerian Mentha essential oils against four fungi: Botrytis cinerea, Penicillium expansum, Monilinia laxa, and M. fructigena. All oils demonstrated very good inhibition especially against B. cinerea, M. laxa, and M. fructigena. Both Monilinia fungi were extremely sensitive to all Algerian Mentha oils, which suggests that Mentha essential oils have the potential to be used as bio-pesticides to protect fruit trees, such as apple and pear trees, and provides an alternative to chemical pesticides.