Studies on the Sapogenins of Dioscorea tokoro Makino. IV. The Contents of Tokorogenin, Yonogenin and Diosgenin

Abstract (1) Improved isolation of tokorogenin, yonogenin and diosgenin from the rhizomes of D. tokoro Makino collected at Gotenba is described. (2) The sapogenin contents in rhizomes of D. tokoro Makino collected in various districts in Japan were examined by means of chromatography. (3) The sapogenin contents in rhizomes of cultivated plants of D. tokoro Makino were examined and it was found that the plants containing diosgenin as the major ingredient contain very small amounts of tokorogenin and yonogenin or lack them, while those containing large amounts of tokorogenin and yonogenin give only minute yields of diosgenin or lack it.