A PRELIMINARY STUDY OF THE CORRELATION BETWEEN PHYLOGENY, CHEMICAL CONSTITUENTS AND THERAPEUTIC EFFECTS OF RHEUM SPEICES

Forty-eight samples of the root of the Genus Rheum representing 7 sections and 27 species were analysed for their anthraquinone derivatives, rhaponticin, sennosides and purgative activity.The result shows that there are ubiquitous existence of anthraquinbne derivitives in this genus., except Rheum lhasaense, the total anthraquinone content was 1～8%. By means of TLC, emodin, physcion, and chrysophanol were found to be present nearly in all the species, while rhein and sennoside derivitives seemed to be distributed only in the Sect. Palmata. As for rhaponticin, it is obviously present in sections Rheum, Acuminata and Orbicularia, with a notable absence in sections Palmata, Deserticola, Spiciformia and Nobilia (cf. Tab.1). Twelve species selected from different sections were examined chemically and pharmacologically in more detail (cf. Tab. 2 and 3). It was found that the original plants of the official drugs with obvious purgative effect were merely restricted in the Sect. Palmata, e. g. Rheurn palmatum, R. palmaturn var. tanguticum, R. officinale etc.. Furthermore, one or several of the following criteria may serve as the standard of the official Rhubarb, viz., the presence of sennoside derivitives, the occurrence of the reduced form of rhein and aloe-emodin, existance of a certain amount of rhein, either in free or combined form, while the leaves with any kind of palmate incision may also be used as a morphological criterion.The conclusions obtained may be of value to the resource utilization and drug standardization of Rhubarb.