OBJECTIVETo investigate the difference and causes of purgative activity in three species of certified rhubarb, so as to lay steady foundations of further research on assessing purgative activity impersonally by using measurable indexes.

METHODThe potencies of three species were comparied with purgative ED, of mice as quantitative index which were calculated, and activities of Na+ K + -ATP ase in mouse colonic epithelial cell membrane were also investigated . The related purgative contents (conjunct and free rhein, chrysophanol, chrysophanic acid, sennoside A) were detected by HPLC and contents (total anthraquinones, anthraglucosennin; conjunct and free anthraquinones) were detected by UV.

RESULTThere were different purgative activities among three spieces of certified rhubarb. Each purgative ED, of mice was Rheum tanguticum ( ED50 = 0. 37 g x kg (-1)) , R. officinale ( ED50 = 0. 99 g x kg(-1) ) and R. palrnatum from Gansu (ED50 = 1. 83 g x kg(-1)) , the ratio of potency of those was 4. 94: 1. 85: 1. In the meanwhile, the difference of the inhibitory effect on Na+ -K + -ATP ase in mouse colonic epithelial cell membrane and relative purgative components also existed in the three species of certified rhubarb.

CONCLUSIONIt disclosed that there was notable diference of purgative activity and components among three spieces of certified Rhubarb, which probably resulted in the ultimate diference in clinical prescription and the production of Chinese patent medicines.