Chuan Shan Long

Chuan Shan Long is the dried rhizome of Dioscorea nipponica Makino (Dioscoreaceae), a perennial twining vine of cool temperate forests across northeastern China, Korea, Japan, and the Russian Far East. The plant climbs to several meters via slender herbaceous stems bearing alternate, deeply five- to seven-lobed cordate leaves; small dioecious yellow-green flowers give rise to three-winged capsules. The horizontal rhizome is cylindrical, branched, and tough, rich in steroidal saponins including dioscin, which is a commercial precursor for diosgenin. In traditional Chinese medicine it is bitter and slightly cool, entering the Liver and Lung channels; it dispels wind-damp, unblocks the channels, relieves pain, transforms phlegm, and stops cough. It is used for rheumatic joint pain, lumbar pain, chronic bronchitis, and traumatic injury.