The Mechanism Of Postharvest Processing For The Fresh Roots Of Rehmennia Glutinosa Libosch.

The fresh, dried and processed roots of Rehmannia glutinota Libosch. (Scrophulariaceae) are used as Radix Rehmanniae Recens, Radix Rehmanniae Exsiccata and Radix Rehmanniae Preparata, respectively, and they are different in flavor, nature, property and action. It is a typical representative for the same plant being used as different drugs by processing in traditional Chinese medicines.Catalpol and stachyose are the main constituents in the fresh roots of R. glutinosa, and largely decomposed during postharvest processing. The contents of them are significantly different in dried roots from markets, inducing unstable clinical action of the drug. It maybe the inappropriate postharvest processing that cause these differences. The fresh root is dried through baking in traditional method, however, whether this method is the most appropriate should be confirmed. There are two types of baking methods, one is baking the roots at lower temperature first and then at a higher temperature, the other is the opposite. Now it is not clear which one is the better.We proposed that p-glucosidase (β-Glu) and α-galactosidase (α-Gal) may exist in the fresh roots and the traditional baking purpose is to inactivate these enzymes and avoid catalpol and stachyose from enzyme-decomposing; at the same time, baking temperature was controlled at a certain level to avoid the two active constituents from...