Antimicrobial Peptides from Plants: Structural Diversity, Modes of Action, and Antimicrobial Potential

Abstract

Antimicrobial resistance (AMR) has emerged as one of the most prominent global public health crises of the 21st century. As traditional antibiotics face declining efficacy against multidrug-resistant (MDR) pathogens, plant antimicrobial peptides (AMPs) have gained significant attention as potent, multi-targeted alternatives. This review provides a comprehensive analysis of the major plant AMP families, including thionins, defensins, lipid transfer proteins (LTPs), hevein-like peptides, snakins, and cyclotides. These peptides are defined by their small size, cationic nature, and cysteine-rich scaffolds stabilized by complex disulfide bond networks. The structure–activity relationships (SARs) that govern their function, specifically the roles of cationicity, amphipathicity, and glycosylation in pathogen discrimination. The review also provides insights of the multifaceted mechanisms of action employed by plant AMPs, ranging from physical membrane disruption to the sequestration of cell wall precursors and the interference with intracellular metabolic processes, including transcription and translation. The review also discusses the current challenges in clinical translation of use of AMPs, such as metabolic instability and host toxicity, and highlights the role of emerging technologies such as AI-driven design, nanoparticle-based delivery systems, and combinatorial therapies in accelerating the development of plant-inspired AMPs as next-generation tools for sustainable infectious disease management.