Plant-Derived Antifungals for Food Preservation: Structure-Activity Relationships, Molecular Mechanisms and Delivery Technologies

Fungal spoilage and mycotoxin contamination compromise food safety, quality, and shelf life, stimulating interest in plant-derived alternatives to conventional preservatives. This critical narrative review evaluates literature published from 2000 to the date of manuscript submission on the structure–activity relationships, molecular mechanisms, food-matrix behavior, delivery systems, safety, and regulatory translation of plant-derived antifungals. Unlike reviews addressing these topics separately, it integrates chemical structure and QSAR evidence with mechanistic findings, matrix-dependent efficacy, formulation performance, and commercialization requirements. Phenolics, terpenoids, alkaloids, and essential oils can disrupt fungal membranes and cell walls, alter mitochondrial and redox homeostasis, inhibit enzymes, and affect mycotoxin biosynthesis. However, many mechanistic claims remain based on in vitro studies, while proteins, lipids, pH, water activity, and processing conditions can substantially reduce efficacy in foods. Antifungal activity is also distinguished from specific antimycotoxigenic activity, which requires toxin measurements normalized to fungal biomass. Translation should prioritize standardized chemoprofiling, batch-specific potency testing, real-food challenge models, sensory thresholds, beneficial-culture compatibility, release and migration kinetics, toxicological and dietary-exposure assessment, and clearly defined regulatory pathways. These requirements will determine whether promising candidates can become reproducible, safe, and commercially viable food-preservation technologies.