Structure characterization and bioactivities of Ampelopsis grossedentata polysaccharides and their anti-inflammatory effect on TNF-α/IFN-γ-induced atopic dermatitis-like HaCaT keratinocytes.

To explore the anti-inflammatory effect and mechanism of the polysaccharides derived from Ampelopsis grossedentata (AGPs) on atopic dermatitis (AD), three polysaccharide fractions AGP40, AGP60 and AGP80 were obtained using ethanol concentration gradient precipitation. All these polysaccharide fractions contain eight monosaccharides with varying mole ratios and are mainly composed of galactose (59.8 % to 71.4 %), mannose (11.1 % to 22.5 %), and glucuronic acid (9.4 % to 13.9 %). AGP40 and AGP60 exhibited higher molecular weights (Mw) of 1761.7 kDa and 1413.4 kDa, respectively, while AGP80 had a smaller Mw of 26.3 kDa. Methylation and NMR analysis suggested that the three polysaccharides are highly similar in the primary structure including monosaccharide composition and glycosidic linkage types, and contain both α and β configurations. Three AGPs exhibited a certain inhibitory effect on hyaluronidase, and AGP40 and AGP60 demonstrate stronger antioxidant activities than AGP80. In the TNF-α/IFN-γ-induced HaCaT model, AGP40 and AGP60 showed excellent properties to inhibit cell apoptosis, suppress inflammatory cytokines expression, and block TLR4/NF-κB pathway activation. This study demonstrated that the anti-inflammatory efficacy of A. grossedentata polysaccharides in keratinocytes models, offering critical evidence to support the development of AGP-based functional foods as a potential therapeutic strategy for AD.