Studies On The Chemical Constituents Of Rheum Nanum And HPLC-FP Establishing Of Rhubarbs

Rhubarb is a famous traditional medicinal material used in China as cathartic, astringent and hemostatic, promoter of biliary, gastric, pancreatic secretions and antibacterial. There are approximately 60 species in genus Rheum, among which more than 40 species were distributed in China, most of them are often used in folk medicine at some minority regions. In Chinese Pharmacopoeia, however, only three species are recorded as official rhubarbs: R. palmatum, R. tanguticum, and R. officinale. In commercial market radix and rhizoma of unofficial rhubarbs in genus Rheum are often mixed with official rhubarbs, such as R. franzenbachii, R. australe, R. nobile, and R. wittrockii, etc, called "mountain rhubarbs". Their purgative activity are much lower than that of the official rhubarbs, some of which can even induce stomach ache. In order to ensure the safety and curative effectiveness of rhubarb in clinic practice as well as to exploit the rich resource of genus Rheum, the following studies were carried out:1 .The chemical constituents of Rheum nanum were systematically approached, fourteen compounds were isolated from 95% EtOH extract of radix and rhizoma of Rheum nanum and nine of them were identified as chrysophanol ,physcion, emodin, n-hexacosanic acid, sitosterol, daucosterol, glucose, emodin-gentiobioside and rheumylate, among which rheumylate is new compounds; emodin-gentiobioside is firstly isolated from genus Rheum. All nine compounds were first isolated from Rheum nanum.In vitro activity tests showed that at the dosage of 100ug/ml some extracts from Rheum nanum have certain effects on proliferation of various tumor cells, such as Bel-7402 cells, Hela cells and KB cells.2. The HPLC Fingerprints (HPLC-FP) of 111 samples from thirty eight species, four varieties and one forma of genus Rheum were firstly established. HPLC-FP not only offers a new way for identification of rhubarbs through the peaks number, thecharacteristic distribution, characteristic peak, peak team and peaks height but also benefits for the chemotaxonomy research as well as the exploitation of genus Rheum.