Isolation, chemical composition and antioxidant activities of a water-soluble polysaccharide from Cyclocarya paliurus (Batal.) Iljinskaja

A water-soluble polysaccharide was isolated from the water extract of Cyclocarya paliurus (Batal.) Iljinskaja, which is a well-known native health tea in China. This polysaccharide was named as CPP-1. The molecular weight of CPP-1 was determined by high-performance gel permeation chromatography, with an average molecular weight of about 1167 kDa. The analysis of monosaccharide composition in the polysaccharide by gas chromatography revealed that it was a heteropolysaccharide and consisted of d-xylose, l-arabinose, d-glucose, d-galactose, l-rhamnose and d-mannose in a molar ratio of 1.00:9.67:9.65:4.96:3.29:2.70. Furthermore, CPP-1 contains 8.44% of protein and 17 general amino acids, and it is rich in glutamic acid, asparagic acid, leucine, glycine, arginine, tyrosine and alanine. The antioxidant activity of CPP-1 was also evaluated. It was found that CPP-1 exerted significant scavenging effects on DPPH radicals with a value of around 91.4%, compared to the reference controls of BHT (91.2%) and ascorbic acid (98.9%) at a concentration of 400 μg/ml, and with EC50 values of 52.3 μg/ml.