Ultrasonic extraction, Structural Characterization, and Immunoactivity of Polysaccharides From Syzygium jambos (L.) Alston.

This research emphasized the extraction and separation of polysaccharides derived from Syzygium jambos (L.) Alston (PSJAP-5), as well as analyses of their structural characteristics and immunomodulatory activities. This study initially employed response surface methodology to determine the extraction conditions of polysaccharides. The average molecular weight of PSJAP-5 was 58 102 Da, and its monosaccharide composition was galactose, arabinose, galacturonic acid, glucuronic acid, and rhamnose (39.84:29.13:21.97:6.02:4.17). In vitro studies showed that PSJAP-5 promoted the proliferation and phagocytosis of macrophages. Meanwhile, PSJAP-5 (25-200 µg/mL) promoted the release of NO and ROS, and increased the levels of IL-6, TNF-α, and IL-1β. After pretreating macrophages with TLR4, NF-κB, and MAPK inhibitors, the immunoenhancing effects of PSJAP-5 on macrophages treated with the inhibitors were decreased. Similarly, PSJAP-5 promoted the phosphorylation of p38 in the MAPK signaling pathway and reduced the phosphorylation of IκBα in the NF-κB signaling pathway in RAW264.7 cells. PSJAP-5 might serve as a potential immunomodulator for the treatment of diseases characterized by impaired immune function.