Investigations on the anti-aging activity of polysaccharides from Chinese yam and their regulation on klotho gene expression in mice

In this study, Chinese yam polysaccharides (CYP) were extracted from the tuber of Dioscorea opposita Thunb. by hot-water extraction and ethanol precipitation. After deproteinized by the Sevag method, the content of CYP was determined to be 91.77%. The anti-aging activities of the CYP were evaluated in aging mice induced by d-galactose in vitro and in vivo. The results indicated that the CYP not only could enhance the learning ability of mice, but alleviate the spatial memory impairment of mice. Furthermore, the CYP could effectively inhibit the formation of malondialdehyde and enhance the activities of superoxide dismutase, catalase and glutathione peroxidase in brain, liver and kidney tissues of mice. The histological analysis indicated that CYP could significantly alleviate the damages induced by d-galactose in the above tissues. Gene expression studies showed that the CYP could up-regulate the expression of anti-aging klotho gene in brain and kidney. Therefore, it can be concluded that the anti-aging effect of Chinese yam may be achieved by repairing the function of organs and improving the expression of klotho gene in mice.