Antioxidant Potential of Polyphenolic Compounds, Sources, Extraction, Purification and Characterization Techniques: A...

Polyphenolic compounds, which are abundant phenolic metabolites in plants, have attracted significant attention because of their diverse biological activities and robust antioxidant properties. This review uniquely describes the extraction characterization, and application pipeline for polyphenols, emphasizing their mechanistic antioxidant actions and translational challenges. Between 1979 and 2025, approximately 141 relevant studies were critically examined, covering the sources, extraction and purification methods, structural diversity, and biological implications of polyphenols. Special attention is given to bioavailability, dose-dependent effects, and subclass-specific activities. Various extraction techniques, including solvent extraction, supercritical fluid extraction, and solid-phase extraction, have been evaluated along with advanced characterization approaches such as spectroscopy and chromatography. The antioxidant mechanisms of polyphenols, ranging from radical scavenging and metal chelation to modulation of signaling pathways, are described, along with their broad applications in nutrition, medicine, and industry. This focused synthesis highlights not only the current state of knowledge, but also identifies key research gaps in clinical validation, formulation strategies, and industrial adoption, providing a forward-looking perspective for future polyphenol research.