Effect of aging process on the structural features and immunomodulatory activity of Artemisia argyi polysaccharides

Aging can promote the transformation and accumulation of bioactive components through a natural and environmentally sustainable process. In this study, the effects of the aging process (1, 3, and 5 years) on the structural features and bioactivities of Artemisia argyi polysaccharides (AAPs) were compared. Structural investigations indicated that the aging process significantly reduced the uronic acid content and molecular weights of AAPs. Meanwhile, the carbohydrate content and homogeneity of the AAPs increased, while their protein content decreased. Bioactivity analysis suggested that the aging process enhanced the in vitro antioxidant activity of AAPs against ABTS, DPPH, superoxide anion, and hydroxyl radicals. Furthermore, AAPs significantly stimulated the secretion of immune factors (including TNF-α, IL-1β, IL-6, and NO) in RAW 264.7 macrophages, with the medium-molecular-weight AAP-3 exhibiting superior immunomodulatory effects. These findings suggest that AAPs hold considerable potential as antioxidant and/or immunoregulatory ingredients in the food and pharmaceutical industries. Furthermore, this study provides guidance for the identification, detection, selection, and appropriate utilization of A. argyi and its polysaccharides. Detailed analysis of the underlying mechanisms and the structure–bioactivity relationships of AAPs will be the focus of future research.