[Studies on the dynamic trends of diosgenin content in vegetative organs of Dioscorea zingiberensis]

Diosgenin was determined by HPLC to study dynamic trend of diosgenin content in vegetative organs especially the rhizome, and the differences of diosgenin content between strains and between male and female rhizomes of Dioscorea zingiberensis C. H. Wright. The results are as follows: Diosgenin content of biennial seedling rhizome is higher than that of annual seedling rhizome; Diosgenin content of biennial rhizome derived from vegetative propagation is higher than that of annual rhizome derived from vegetative propagation; In piebald leaf strain is higher than in green leaf strain; In male is higher than in female. Diosgenin was not detected in twining stem nor in leaf. Diosgenin content of annual rhizome from vegetative propagation increased slowly at early stage, and it increased comparatively quickly at later stage; Diosgenin content of biennial rhizome at the stage of blossom is the highest, and it is the lowest at the later stage of bloom, afterwards it increases gradually. So cultivated variety of higher output and higher fastness should be chosen from the piebald leaf strain. The right time to collect rhizome should be at the stage of twining stem withering.