Diosgenin (DG)

Diosgenin, a steroid sapogenin, is the product of hydrolysis by acids, strong bases, or enzymes of saponins, extracted from the tubers of Dioscorea wild yam, such as the Kokoro. The sugar-free (aglycone), diosgenin is used for the commercial synthesis of cortisone, pregnenolone, progesterone, and other steroid products. The glycoside dioscin from the Mexican wild yam root, Dioscorea, constituted the first significant sapogenin plant source for steroid drugs. Hydrolysis of this saponin leads to scission of the trisaccharide at the 3-position and the formation of the aglycone, diosgenin. Treatment of this acetal with hot acetic anhydride in the presence of toluenesulfonic acid leads initially to protonation of one of the acetal oxygens followed by elimination to form an enol ether. Oxidation by means of chromium trioxide leads to preferential attack at the electron-rich enol ether double bond.