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

FAIT, M.E.; VÁZQUEZ, R.F.; MATÉ, S.; DE FREITAS, C.D.T.; COMELLES, F.; CLAPÉS, P.; BAKÁS, L.; MORCELLE, S.R.

San Miguel de Tucumán

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

Sociedad Argentina de Biofísica

The antifungal activity of twonovel arginine-based compounds (BzArg-NHC10 and Bz-Arg-NHC12), which weresynthesized by an enzymatic strategy, was studied against phytopathogenic fungi(Fusarium oxysporum, Fusarium solani, Colletotrichum gloeosporioides and Colletotrichumlindemuthianum). A commercial cationic disinfectant, Cetrimide (alkyl trimethylammonium bromide mixture), was used for comparison. Critical micelleconcentration was determined by tensiometry for both compounds, being 0.23 mMfor Bz-Arg-NHC10 and 0.085 mM for Bz-Arg-NHC12. Inhibition of vegetative growthand spore germination was also investigated for phytopathogenic fungi. Ingeneral, for the vegetative growth, the most potent arginine-based compound wasBz-Arg-NHC10, showing IC50 values ranging from 45 to 71 µM after 72 hs ofexposure. The three compounds tested (considering Cetrimide for comparison)interfered in the spore?s development of the four species studied. Experiments inlipid monolayers composed by dioleoylphosphatidylcholine (PC), phosphatidylethanolamine(PE) and ergosterol (ERG) confirmed that Bz-Arg-NHC10 has higher antifungal potencythan Bz-Arg-NHC12. The possible mechanism of antifungal activity of theinvestigated compounds could involve the penetration of surfactant moleculesinto the cytoplasm and production of reactive oxygen species (ROS).