Ribes nigrum L. polysaccharides as multifunctional bioactive agents: current advances, challenges, and future directions in functional food and pharmaceutical development

Ribes nigrum L. (Blackcurrant) is a widely cultivated shrub that originated in the temperate and cold regions of the Northern Hemisphere. It has been used for its medicinal properties throughout history and is rich in various bioactive compounds, including polysaccharides. Published studies have shown that R. nigrum polysaccharides (RNPs) are key macromolecules with multiple health-promoting effects, such as antioxidant, anti-diabetic, immunomodulatory, anti-inflammatory, anti-tumor, anti-aging, anti-gout, etc. Although extensive research has been conducted on the extraction and purification methods, structural characteristics, and pharmacological activities of RNPs in the fruits, seeds, and other parts of the plant, knowledge regarding their structure-activity relationships, safety features, and pharmacokinetic behaviors is still limited. This is mainly due to the complex and variable structure of natural polysaccharides, which makes it difficult to precisely characterize them. This review systematically summarizes the latest progress in the extraction, purification, structural characterization, biological activities, and potential applications of RNPs, and discusses the current challenges and future prospects of using them as therapeutic drugs and functional food components. It also points out that future research should combine multiple analytical techniques (such as atomic force microscopy) to address the limitations of current studies.