Hydrogen bond regulation to promote the direct production of diosgenin from Dioscorea zingiberensis rhizomes

Herein, a renewable system consisted of tartaric acid and isopropanol was developed to produce diosgenin efficiently from Dioscorea zingiberensis rhizomes. The yield of diosgenin reached 4.15% comparable to the highest value reported in previous researches. The combination of experiment and DFT calculation revealed that the acid-alcohol system could regulate the hydrogen bond interaction of each component in the rhizomes to disassemble the connection network and promote the release of saponin. Meanwhile, the intramolecular hydrogen bond of tartaric acid and the steric hindrance effect of isopropanol could prevent the esterification reaction and maintain the strong acidity of the system for the high yield of diosgenin. The scale-up experiment with a 100-fold feeding capacity was also conducted successfully. Furthermore, the technological process integrated with purification of diosgenin, recovery of organic acid and solvent and upgrading of residual solid to porous carbon materials has been established systematically to verify the prospective of industrialization.