In vitro toxicological evaluation of mesoporous silica microparticles functionalised with carvacrol and thymol

Pore engineering of micro/mesoporous nanomaterials for encapsulation, controlled release and variegated applications of essential oils

Essential oils have become increasingly popular in fields of medical, food and agriculture, owing to their strongly antimicrobial, anti-inflammation and antioxidant effects, greatly meeting demand from consumers for healthy and safe natural products. However, the easy volatility and/or chemical instability of active ingredients of essential oils (EAIs) can result in the loss of activity before realizing their functions, which have greatly hindered the widely applications of EAIs. As an emerging trend, micro/mesoporous nanomaterials (MNs) have drawn great attention for encapsulation and controlled release of EAIs, owing to their tunable pore structural characteristics. In this review, we briefly discuss the recent advances of MNs that widely used in the controlled release of EAIs, including zeolites, metal-organic frameworks (MOFs), mesoporous silica nanomaterials (MSNs), and provide a comprehensive summary focusing on the pore engineering strategies of MNs that affect their controlled-release or triggered-release for EAIs, including tailorable pore structure properties (e.g., pore size, pore surface area, pore volume, pore geometry, and framework compositions) and surface properties (surface modification and surface functionalization). Finally, the variegated applications and potential challenges are also given for MNs based delivery strategies for EAIs in the fields of healthcare, food and agriculture. These will provide considerable instructions for the rational design of MNs for controlled release of EAIs.

Immobilization of Natural Antimicrobial Compounds on Food-Grade Supports as a New Strategy to Preserve Fruit-Derived Foods

The use of natural antimicrobials in the food industry is being proposed as an eco-friendly postharvest technology to preserve fruit-derived foods. In this context, this systematic review aims to describe and discuss the application of naturally occurring antimicrobial compounds in the processing of fruit-derived foods by the PRISMA methodology. In a first step, the use of free natural antimicrobials was investigated as an approach to identify the main families of bioactive compounds employed as food preservatives and the current limitations of this dosage form. Then, the use of immobilized antimicrobials, in an innovative dosage form, was studied by distinguishing two main applications: addition to the food matrix as preservatives or use during processing as technological aids. Having identified the different examples of the immobilization of natural antimicrobial compounds on food-grade supports, the mechanisms of immobilization were studied in detail to provide synthesis and characterization guidelines for future developments. Finally, the contribution of this new technology to decarbonization and energy efficiency of the fruit-derived processing sector and circular economy is discussed in this review.

In vivo toxicity assessment of eugenol and vanillin-functionalised silica particles using Caenorhabditis elegans

The toxicological properties of different silica particles functionalised with essential oil components (EOCs) were herein assessed using the in vivo model C. elegans. In particular, the effects of the acute and long-term exposure to three silica particle types (SAS, MCM-41 micro, MCM-41 nano), either bare or functionalised with eugenol or vanillin, were evaluated on different biological parameters of nematodes. Acute exposure to the different particles did not reduce nematodes survival, brood growth or locomotion, but reproduction was impaired by all the materials, except for vanillin-functionalised MCM-41 nano. Moreover, long-term exposure to particles led to strongly inhibited nematodes growth and reproduction. The eugenol-functionalised particles exhibited higher functionalisation yields and had the strongest effects during acute and long-term exposures. Overall, the vanillin-functionalised particles displayed milder acute toxic effects on reproduction than pristine materials, but severer toxicological responses for the 96-hour exposure assays. Our findings suggest that the EOC type anchored to silica surfaces and functionalisation yield are crucial for determining the toxicological effects of particles on C. elegans. The results obtained with this alternative in vivo model can help to anticipate potential toxic responses to these new materials for human health and the environment.