Fungicidal mechanism of Arginine-based surfactants against phytopathogenic fungal spores via membrane disturbance

FAIT, MARÍA ELISA; VAZQUEZ, ROMINA; MATÉ, SABINA; DE FREITAS, CLEVERSON D. T.; COMELLES, FRANCESC; CLAPES, PERE; BAKÁS, LAURA; MORCELLE, SUSANA

San Miguel de Tucumán

Congreso; III Latin American Federation of Biophysical Societies (LAFeBS)/ IX IberoAmerican Congress of Biophysics/ XLV Reunión Anual SAB 2016.; 2016

Sociedad Argentina de Biofísica

The antifungal activity of two novel arginine-based compounds (BzArg-NHC10 and Bz-Arg-NHC12), which were synthesized by an enzymatic strategy, was studied against phytopathogenic fungi (Fusarium oxysporum, Fusarium solani, Colletotrichum gloeosporioides and Colletotrichum lindemuthianum). A commercial cationic disinfectant, Cetrimide (alkyl trimethyl ammonium bromide mixture), was used for comparison. Critical micelle concentration was determined by tensiometry for both compounds, being 0.23 mM for Bz-Arg-NHC10 and 0.085 mM for Bz-Arg-NHC12. Inhibition of vegetative growth and spore germination was also investigated for phytopathogenic fungi. In general, for the vegetative growth, the most potent arginine-based compound was Bz-Arg-NHC10, showing IC50 values ranging from 45 to 71 µM after 72 hs of exposure. The three compounds tested (considering Cetrimide for comparison) interfered in the spore’s development of the four species studied. Experiments in lipid monolayers composed by dioleoylphosphatidylcholine (PC), phosphatidylethanolamine (PE) and ergosterol (ERG) confirmed that Bz-Arg-NHC10 has higher antifungal potency than Bz-Arg-NHC12. The possible mechanism of antifungal activity of the investigated compounds could involve the penetration of surfactant molecules into the cytoplasm and production of reactive oxygen species (ROS).