Analysis of Differences in the Chemical Composition of Glycosides and Sugars between Four Forms of Fresh Rehmanniae Radix.

ABSTRACT

Fresh Rehmanniae Radix, as well as its processed products, are widely used in the clinical practice of traditional Chinese medicine. It is mainly available in four forms fresh Rehmanniae Radix, raw Rehmanniae Radix, prepared Rehmanniae Radix, and nine-steamed, nine-dried Rehmanniae Radix. Pharmacological studies have shown that all Rehmanniae Radix forms contain iridoid glycosides and sugar compounds with various effects, including hypoglycemic, anti-inflammatory, neuroprotective, immunological enhancement, and bone marrow hematopoiesis-promoting activities. Differences in the efficacy among these Rehmanniae Radix forms and their processed products have been attributed to variations in their chemical compositions, particularly in iridoid glycosides and sugar compounds; however, the specific compositional differences in glycosides and sugars among the four forms of Rehmanniae Radix have not been clarified. Therefore, this study aims to qualitatively characterize the iridoid glycosides and sugar compounds in fresh Rehmanniae Radix, raw Rehmanniae Radix, prepared Rehmanniae Radix, and nine-steamed, nine-dried Rehmanniae Radix.