Inhibition of Calcium Oxalate Formation and Antioxidant Activity of Carboxymethylated Poria cocos Polysaccharides

作者：Chuangye Li, Li Liu, Yao‐Wang Zhao, Jia-Yun Chen, Xin‐Yuan Sun, Jian‐Ming Ouyang · 发表于：Oxidative Medicine and Cellular Longevity · 年份：2021 · DOI：10.1155/2021/6653593 · 被引用次数：30 · 研究领域：Polysaccharides and Plant Cell Walls、Seaweed-derived Bioactive Compounds、Algal biology and biofuel production

Three carboxymethylated Poria cocos polysaccharides (PCP‐C1, PCP‐C2, and PCP‐C3) with ‐COOH contents of 6.13%, 10.24%, and 16.22%, respectively, were obtained by carboxymethylation of the original polysaccharide (PCP‐C0), which has a molecular weight of 4 kDa and a carboxyl (‐COOH) content of 2.54%. The structure of the PCP‐Cs was characterized by FT‐IR, 1 H NMR, and 13 C NMR spectra. The four PCP‐Cs exhibited antioxidant activity, and their ability to scavenge radicals (hydroxyl and DPPH) and chelate ferrous ions was positively correlated with the degree of carboxymethylation. As the content of ‐COOH groups in the PCP‐Cs increases, their ability to regulate the growth of calcium oxalate (CaOx) crystals was enhanced, thus inhibiting the growth of calcium oxalate monohydrate (COM) crystals and inducing the formation of more calcium oxalate dihydrate (COD) crystals. The formed CaOx crystal was more round and blunt, the absolute value of the Zeta potential on the crystal surface increased, and the aggregation between crystals was inhibited. Thermogravimetric analysis curves showed that the proportions of PCP‐C0, PCP‐C1, PCP‐C2, and PCP‐C3 incorporated into the crystal were 20.52%, 15.60%, 10.65%, and 9.78%, respectively, in the presence of 0.4 g/L PCP‐Cs. PCP‐C protection resisted oxidative damages of human kidney proximal tubular epithelial cells (HK‐2) caused by oxalate, resulting in increased cell viability and superoxide dismutase activity and decreased reactive oxygen speci...