OBJECTIVETo study the toxicity-attenuating effect and the dose-toxicity relationship of rhubarb by processing based on correspondence.

METHODThe effects of different processed materials of rhubarb on the hepatic and renal functions of mice was researched in a way of parallel comparison, as well as the chemical alteration induced by processing was observed. Correspondence analysis, a kind of multivariate statistical analysis, was performed to explore the dose-toxicity relationship of processed materials of rhubarb.

RESULTNo obvious toxic effect was found in mice after single intragastric administration of crude drug of rhubarb at dosage of 76 g x kg(-1), while some lesions to liver and kidney tissues were observed in mice after repeated administration of rhubarb and its processed materials for 14 days at the same dosage. In the correspondence analysis diagram, it could be deduced that there was definite dose-toxicity relationship of processed rhubarb as the distance between trial groups and control group increased along with the dosage and the toxicity. The distance of the processed rhubarb showed as the following consequence: crude drug of rhubarb > vinegar-processed rhubarb > alcohol-processed rhubarb > steamed rhubarb > carbonized rhubarb > Qingning pian. Theerefoer, the toxicity of processed rhubarb was much lower than that of crude drug and the extent of toxicity attenuation was related to the processing intensity. Meanwhile, the toxicity-attenuating effect of processed rhubarb was related to the decline of the contents of both anthraquinone glycosides and tannins, and the former was contributed remarkably to toxicity.

CONCLUSIONThe toxicity-attenuating effect of processed rhubarb was verified in this study and the toxicity of steamed rhubarb attenuated notably while the pharmacological substances degraded little. The correspondence analysis would be useful to assess the pharmacological and toxic effects with multiple indexes of traditional Chinese medicines.