Investigation the Distributions and Pharmacokinetics of Five Rhubarb Anthraquinones in Rabbits and Rats

Rhubarb (Dahuang in Chinese), a well-known chinese herbal medicine, has long been used in the world and is officially listed in Chinese Pharmacopoeia which containing three species, Rheum palmatum L., Rheum officinale Bail and Rheum tanguticum Maxim. ex Balf. [1]. It is also formally listed in European and Japanese Pharmacopoeia [2,3]. This important herbal medicine has been discerned for centuries in traditional medicine for its multiple pharmacological actions include antibacterial, laxative, antispasmodic and hemostatic [4,5]. The main effective components of Rhubarb are five anthraquinones, namely rhein, emodin, aloe-emodin, chrysophanol and physcion. Most of which are glycoside. More than 16 pure compounds which about 3-5% constituents of Rhubarb have been separated. These are the basis for the quality control of rhubarb and other plant drugs from Rheum, Cassia and Polygonum genera. The chemical structures of these AQs and internal standard (IS) are shown in Figure 1. We designed the experiment for tentative discussing the pharmacokinetic parameters and the excretion of Rhubarb AQs in vivo.