Quality and Safety of Polygonum multiflorum Thunb.: Bridging Ancient Processing Wisdom with Modern Scientific Validation

Polygonum multiflorum Thunb. (PM), a renowned medicinal herb in Traditional Chinese Medicine (TCM), exhibits dual pharmacological properties of therapeutic efficacy and potential hepatotoxicity, largely influenced by its geographic origin and processing methods. This review synthesizes current evidence on the variations in bioactive constituents (e.g., anthraquinones, stilbenes, and polysaccharides) across different cultivation regions, highlighting the role of climatic and soil factors in shaping its phytochemical profile. Critically, the traditional "nine-steaming and nine-sun-drying" (JZS) processing method is shown to significantly reduce hepatotoxicity by converting free anthraquinones into safer polymeric forms while preserving key active compounds like 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (TSG). We further discuss the limitations of existing quality standards and propose a multidimensional evaluation framework integrating metabolomics, fingerprinting, and bioactivity assays to ensure consistency and safety. By integrating traditional knowledge with modern scientific validation, this review offers practical insights for standardizing PM production and enhancing its clinical use, addressing both its historical significance and current challenges in global herbal medicine.