*Article* **Isolation, Characterization and Antioxidant Activity of Yam Polysaccharides**

**Zhedong Li, Wenhao Xiao, Jianhua Xie, Yi Chen, Qiang Yu, Weidong Zhang and Mingyue Shen \***

State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China; 15639052109@163.com (Z.L.); xwh970726@163.com (W.X.); jhxie@ncu.edu.cn (J.X.); chenyi15@ncu.edu.cn (Y.C.); yuqiang8612@163.com (Q.Y.); 15502618197@163.com (W.Z.)

**\*** Correspondence: shenmingyue1107@163.com; Tel./Fax: +86-791-8830-4347

**Abstract:** This study aimed to characterize the structure of Chinese yam (*Dioscoreae Rhizoma*) polysaccharide (CYP) and to investigate its protective effect against H2O2-induced oxidative damage in IEC-6 cells. The chemical composition and structural characteristics of the samples were analyzed by chemical and instrumental methods, including high-performance gel permeation chromatography, high-performance anion-exchange chromatography (HPAEC), Fourier transformed infrared (FT-IR), ultraviolet (UV), and scanning electron microscopy (SEM). Antioxidant activity was evaluated by establishing a cellular model of oxidative damage. The molecular weight of CYP was 20.89 kDa. Analysis of the monosaccharide composition revealed that CYP was primarily comprised of galactose (Gal), glucose (Glu), and galacturonic acid (GalA), and the ratio between them was 28.57:11.28:37.59. Pretreatment with CYP was able to improve cell viability, superoxide dismutase (SOD) activity, and reduce intracellular reactive oxygen species (ROS) production and malondialdehyde (MDA) content after H2O2 injury. CYP also attenuated oxidative damage in cells through the mitogen-activated protein kinase (MAPK) signaling pathway. This study showed that CYP was an acidic heteropolysaccharide with a good protective effect against oxidative damage, and it thus has good prospects in food and biopharmaceutical industries.

**Keywords:** Chinese yam; polysaccharide; structural characterization; oxidative stress; antioxidant activity
