Plant-derived exosome-like nanoparticles as candidate nano-prebiotics: from structure-enabled delivery to host-microbiota interface remodeling

Gut ecosystem homeostasis depends on coordinated interactions among commensal microorganisms, the mucosal barrier, and the immune system. Conventional prebiotics rely on selective utilization by host microorganisms, but their efficacy is shaped by baseline microbiota and disease-associated ecological constraints. Plant-derived exosome-like nanoparticles (PELNs) are naturally occurring membrane-bound nanoparticles characterized by source-dependent lipid interfaces and associated molecular components, including small RNAs, proteins, polysaccharides, and plant-derived metabolites. We evaluate selected PELNs within a provisional "candidate nano-prebiotic" framework that allows particle- or component-mediated mechanisms to coexist with microbial utilization of fermentable components without implying equivalence to consensus-defined prebiotics. We critically assess evidence for microbe-directed and host-mediated effects on microbial functions, microbiota-derived metabolites, epithelial barrier integrity, and mucosal immunity, particularly in inflammatory bowel disease (IBD). Current evidence remains heterogeneous and predominantly preclinical, with major uncertainties regarding particle identity, component-specific causality, in vivo fate, microbiota dependence, dose plausibility, and mechanistic generalizability. We further define conceptual boundaries among PELNs, conventional prebiotics, and engineered nano-prebiotics and identify priorities for standardization, causal testing, food-relevant exposure assessment, safety evaluation, and mechanistically informed human studies.