Nanoemulsions containing mancozeb and eugenol: development, characterization, and antifungal activity against Glomerella cingulata

The grape culture is quite affected by fungi. Among them is Glomerella cingulata, whose control is carried by synthetic fungicides such as mancozeb, which can cause damage to human and environmental health. An alternative is the use of natural fungicides, such as eugenol. It has already proven antifungal activity but has instability problems. In this context, nanoencapsulation would be a possibility to minimize the mancozeb toxicity and the eugenol instability. In this study, nanoemulsions containing eugenol and mancozeb, isolated and in association, were prepared by the spontaneous emulsification method. Afterwards, the antifungal activity, through the macrodilution technique in broth and the physicochemical stability of these formulations were evaluated. The nanoemulsions presented adequate nanometric characteristics with diameter between 180 and 210 nm, polydispersity index less than 0.3, negative zeta potential and acid pH. Besides good physicochemical stability. The compounds when nanoencapsulated presented an antifungal activity against G. cingulata with efficacy 103 and 3 times better for mancozeb and eugenol, respectively, compared to its free form. The study demonstrates the viability of obtaining nanoemulsions containing mancozeb and/or eugenol with antifungal activity against of G. cingulata, having these an innovative character for the treatment of vine-growing pests.