Comparison of structural and antioxidant activity of polysaccharide extracted from truffles

As the main component of truffles, polysaccharides have a variety of biological activities such as anti‐oxidation, anti‐tumor, and hypoglycemic activity, and these activities are closely related to its structure. In this study, Tuber Aestivum crude polysaccharide (TACP) and Tuber Melanosporum crude polysaccharide (TMCP) were obtained from Tuber Aestivum and Tuber Melanosporum by using microwave‐assisted hot water, and then the Sephadex G‐200 column was utilized to further separate and purify Tuber Aestivum polysaccharide (TAP) and Tuber Melanosporum polysaccharide (TMP) from TACP and TMCP. The structural characterization results showed that the molecular weight of TAP was 2.18 × 104 kDa, while TMP was 8.79 × 103 kDa. Although the two polysaccharide components were mainly composed of mannose (Man) and glucose (Glc), the molar ratio of Man and Glc in TAP was 14.76: 12.31, with a molar ratio of 5.43:10.94 in TMP. Furthermore, the antioxidant activity of two polysaccharide components was evaluated. TAP and TMP could protect porcine jejunal epithelial (IPEC‐J2) cells from oxidative damage by H2O2, but TAP exhibited stronger antioxidant effects. It was mainly reflected that TAP could increase the secretion level of intracellular antioxidant enzymes (superoxide dismutase and catalase) in IPEC‐J2 cells, and had a significant effect on the total antioxidant capacity of cells. The reactive oxygen species and malondialdehyde had better scavenging ability at the concentration of 20 µg/ml. The difference between TAP and TMP may be due to the dissimilar structure. Its structure‐activity relationship needs further study. Practical Application The structure of TAP and TMP were different, and TAP had higher molecular weight. Besides, TAP and TMP can protect IPEC‐J2 cells from oxidative stress, providing a theoretical basis for developing potential antioxidant drugs of practical significance.