Formulation of nanoemulsions enriched with chalcone-based compounds: formulation process, physical stability, and antimicrobial effect

Salmonellosis has a high power of dissemination and dispersion of strains resistant to conventional antimicrobials, which constitutes a public health problem. Nanoemulsions can enhance the efficacy of antimicrobials compared to conventional drug administration, with reduced side effects and prolonged release. The aim of this study is to produce nanoemulsions by high-energy method using alginate and gum arabic matrices to evaluate the effect of three types of chalcone on the inhibition of S . minnesota and to propose an alternative candidate to overcome antibiotic resistance in pathogenic bacteria. Nanoemulsions with nanosized spherical particles obtained with gum arabic are more stable over time than those with alginate by the lower sedimentation values and the smaller size of the droplets. The antibacterial inhibition test against S. minnesota revealed that the chalcone 1,5-di(thiophen-2-yl)penta-1,4-dien-3-one (TIOF) and 1,5-bis(4-ethoxyphenyl)penta-1,4-dien-3-one (ETOX) and their nanoemulsions presented an equivalent effect compared to the positive control (sulfamethoxazole-trimethoprim). On the other hand, although the chalcone 1,9-diphenylnone-1,3,6,8-tetraen-5-one (CNM) presented low inhibitory capacity, they presented an increasing in the inhibitory activity of 164%, when they were in the nanoemulsion form in comparison with the free form, and equivalent activity to the positive control. Nanoemulsions of gum arabic with 1,9-diphenylnone-1,3,6,8-tetraen-5-one (CNM) also presented lower cytotoxic effects, being a promising inhibitor against S . minnesota . Graphical abstract