A Comprehensive Review of Phenolic Compounds in Horticultural Plants.

Phenolic compounds (PCs) are key secondary metabolites in horticultural plants that are structurally categorized into flavonoids, simple phenols, stilbenes, and tannins. Synthesized via the shikimate and phenylpropanoid pathways, the metabolism of PCs is regulated by transcription factors (e.g., MYB and bZIP) and influenced by genetic backgrounds and environmental stresses (e.g., temperature and UV), thereby leading to species- or tissue-specific distribution patterns. Advanced extraction/separation techniques (e.g., ultrasonic-assisted and HPLC) have enabled systematic PC characterization. Functionally, PCs enhance plant stress resistance (abiotic/biotic) through antioxidant activity, cell wall reinforcement, and defense signaling. Their dual roles as reactive oxygen species scavengers, and signaling molecules are integral. This review synthesizes the classification, metabolic regulation, and biological functions of PCs, providing a scientific basis for improving PC content in horticultural plants with the aim of enhancing stress resilience, postharvest and storage quality, and nutritional value for sustainable agriculture.