Chemical Studies on Crude Drug Processing. VII. On the Constituents of Rehmanniae Radix. (1) : Absolute Stereostructures of Rehmaglutins A, B, and D Isolated from Chinese Rehmanniae Radix, the Dried Root of Rehmannia glutinosa LIBOSCH.

Abstract

An iridoid alcohol, rehmaglutin A, and two chlorinated iridoids, rehmaglutins B and D, were isolated from the less polar fraction of Chinese Rehmanniae Radix [the dried root of Rehmannia glutinosa LIBOSCH. (Kan-jio in Japanese)], together with rehmaglutin C, rehmaionoside C, jio-cerebroside, and acteoside. The absolute configurations of rehmaglutins A, B, and D were established on the basis of chemical and spectral evidence which included the chemical derivations of rehmaglutins from the known iridoid glycoside catalpol and the application of the bezoate chirality method.