Studies on the Constituents of Polygonaceous Plants. IV

Constituents of Japanese Rhubarb (Rheum undulatum L.)

Abstract

Dried root of Rheum undulatum was consecutively extracted with ethanol and ether, and by transition to alkaline solution, hydroxyanthraquinones, such as chrysophanic acid, emodin, and aloe-emodin, and rhapontin were obtained besides unknown crystals, oily substance, and resins. Rhein and emodin monomethyl ether were detected during the isolation process but they were not obtained as crystals. Confirmation of hydroxyanthraquinones was made by the same procedures as in the case of Polygonum cuspidatum.