Secreted Enzyme-Responsive System for Controlled Antifungal Agent Release

[EN] Essential oil components (EOCs) such as eugenol play a significant role in plant antimicrobial defense. Due to the volatility and general reactivity of these molecules, plants have evolved smart systems for their storage and release, which are key prerequisites for their efficient use. In this study, biomimetic systems for the controlled release of eugenol, inspired by natural plant defense mechanisms, were prepared and their antifungal activity is described. Delivery and antifungal studies of mesoporous silica nanoparticles (MSN) loaded with eugenol and capped with different saccharide gates-starch, maltodextrin, maltose and glucose-against fungus Aspergillus niger-were performed. The maltodextrin- and maltose-capped systems show very low eugenol release in the absence of the fungus Aspergillus niger but high cargo delivery in its presence. The anchored saccharides are degraded by exogenous enzymes, resulting in eugenol release and efficient inhibition of fungal growth.This research was funded by the project NutRisk (Project No: CZ.02.1.01/0.0/0.0/16_019/0000845), the Spanish Government (projects RTI2018-100910-B-C41, RTI2018-101599-B-C22-AR and RTI2018-101599-B-C21-AR (MINECO/FEDER)) and the GeneralitatValenciana (project PROME-TEO 2018/024); by the National Agency for Agricultural Research of the Ministry of Agriculture of the Czech Republic under project Biostore QK21010064; and by the Research Infrastructure METROFOOD-CZ supported by the Ministry of Education, Youth, and Sports of the Czech Republic under project number LM201810. A.B. thanks the Spanish Government for financial support.Bernardos Bau, A.; Bozik, M.; Montero, A.; Pérez-Esteve, É.; García-Casado, E.; Lhotka, M.; Frankova, A.... (2021). Secreted Enzyme-Responsive System for Controlled Antifungal Agent Release. Nanomaterials. 11(5):1-14. https://doi.org/10.3390/nano11051280S11411

Testing the antimicrobial activity of essential oils

The vapor phase of some essential oils proved to have antimicrobial activity. Utilization of the vapor phase of Eos is presently understood as one of the possible alternatives to synthetic food preservatives which could be used in the future. However, testing the vapor phase of EOs against microorganisms causing food-borne diseases (e.g. Salmonella enteritidis or Staphylococcus aureus) or food spoilage is relatively new. Consequently, due to the large number of known EOs, research on their antimicrobial activity is still largely in the phase of in vitro rather than in vivo testing. Moreover, no standard and reliable method for fast screening of a wide range of samples exists. Thus, the aim of this study is to show results concerning tests of the antimicrobial activity of EOs against S. enteritidis or S. aureus, which were conducted by two modifications of the disc volatilization method we developed. The lately developed method has the potential to become widely used for fast screening of EO antimicrobial activity in the vapor phase