Fabricating Jerusalem artichoke polysaccharide-Zn (II) complexes to enhance hepatoprotective activity in vitro: Structural characterization and biological evaluation

Abstract

This study aimed to modify the structure of Jerusalem artichoke polysaccharides (JPs) with Zn (II) and evaluate the improvement of in vitro hepatoprotective activity by this chemical modification. The obtained JP-Zn (II) complexes exhibited a higher molecular weight and an altered monosaccharide composition compared with native JPs. Structural characterization suggested that the chelation of JPs with Zn (II) occurred mainly at the O–H of the carboxyl and hydroxyl groups and affected the C–O, C–O–C, and O–C–O structures. After modification with Zn (II), the crystallinity of JPs decreased, accompanied by an increased Cotton effect and enhanced thermal stability (in the region of 30–230 °C). The aqueous solution of JP-Zn (II) complexes was relatively stable at different temperatures (40–80 °C), pH (2–10) and storage times (0–28 d), with good resistance to simulated gastrointestinal digestion. JP-Zn (II) complexes showed lower cytotoxicity and stronger hepatoprotective activities (dose: 1.25–10.0 µg/mL) than JPs in H₂O₂-damaged HepaRG cells. Taken together, this study demonstrated that the modification of Zn (II) could enhance the functional properties of the parent polysaccharides and offered promising dietary formulations with enhanced hepatoprotective effects and Zn (II) supplements in functional foods.