Immunological activity of peach pectins: Insights from cells to animals.

Pectins are non-toxic, natural anti-inflammatory polysaccharides, but the immunomodulatory potential of peach pectins (PPs) remains underexplored. This study examined the immunomodulatory effects of three PP fractions: chelate-soluble pectin (CSP), sodium carbonate-soluble pectin (SSP), and enzymatic SSP (ES). These were tested on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and cyclophosphamide (CTX)-induced immunosuppressed mice. The study also investigated their underlying molecular mechanisms. In vitro, SSP and ES significantly increased nitric oxide production by nearly three times, enhanced phagocytic activity by about 45 %, and reduced ROS levels by 35-40 % compared to control. CSP showed a dual role by activating p38 and c-Jun N-terminal kinase (JNK) pathways while inhibiting nuclear factor κB (NF-κB) signaling. ES promoted a pro-inflammatory phenotype, with IL-1β and TNF-α levels elevated to 2.7- and 3.4-fold of control, and IL-6 increased more than thirtyfold, while IL-10 showed a slight decrease. Furthermore, SSP exhibited partial anti-inflammatory effects, decreasing TNF-α and NF-κB activity while maintaining IL-6 level (approximately 20 % of the LPS group) and reducing IL-10 level (nearly 8 % of the LPS group). In vivo, SSP improved body weight, restored red blood cell count and hemoglobin levels to nearly normal, and enhanced specific immune responses, indicating immune recovery. These findings highlight SSP as a promising candidate for developing functional foods that support immunity.