Comparison of the Polysaccharide Content of Cultivated Dioscorea nipponica Makino and Research on Pharmacologic Activity of Polysaccharide

Dioscorea nipponica Makino, a perennial herb growing in mountainous areas of the Chinese Changbai mountains and Korean peninsula, has long been used as a folk medicine for bronchitis, asthma, and rheumatoid arthritis. Due to these therapeutic properties, wild Dioscorea nipponica Makino resources become less and less, some wild species have been tamed to be cultivated ones. In this paper, we compared the content of polysaccharide in stem root between biennial and three-year old cultivated Dioscorea nipponica Makino. The results indicated there is no significant difference between these samples, while in different harvest stages (from the early of June to the late of September), the polysaccharide content displayed significant difference (p < 0.01). The polysaccharide content in the Epigean leaves also showed the same change rule in the growth stages (from the late of June to the late of July). Moreover, the pharmacologic activity analysis implied that the polysaccharide of cultivated Dioscorea nipponica Makino could reduce the hyperlipidemia mice serum cholesterol (TC), triglyceride (TG) low density lipoprotein cholesterol (LDL-C) level, while increase high density lipoprotein cholesterol (HDL-C) level. These results demonstrated that the polysaccharide accumulation in biennial cultivated Dioscorea nipponica Makino almost get the same standard as three-year old ones, and the polysaccharide from epigean leaves also have some therapeutic properties as the stem root.