[Dose-toxicity-effect relationship between licorice combined with rhubarb in purgation]

The dose-toxicity-effect relationship between licorice combined with rhubarb in purgation was studied. A total of 108 ICR mice were divided into control group,model group,positive group,low,medium and high-dose rhubarb groups,and low,medium and high-dose rhubarb-liquorice decoction group. After 6 days of continuous administration of loperamide hydrochloride,the constipation model of mice was replicated,and each group was given lactulose,different doses of rhubarb and rhubarb-liquorice decoction for 14 days. After administration,the defecation characteristics,blood biochemistry,liver,kidney and colon pathological changes in each group were compared. Based on the objective weight given by factor analysis,the dose-toxicity-effect relationship was comprehensively analyzed by multi-index scoring method. Two common factors were extracted by factor analysis,representing effect and toxicity respectively. The results showed that rhubarb could exert a diarrhea effect at the dosage of 1/2,2 and 8 times of the high limit set forth in the Chinese Pharmacopoeia,increase the defecation volume and the intestinal tract propulsion rate,reduce the time of anal and the oral transmission,and increase the water content of feces. The combination with licorice could alleviate its diarrhea effect,especially at the dosage of 1/2 times of the high limit set forth in the Chinese Pharmacopoeia. However,rhubarb showed obvious hepatic and colon toxicities at the dosage of 2 and 8 times of the high limit set forth in the Chinese Pharmacopoeia,and the combination with licorice could significantly reduce its toxicity. It shows that licorice has a " mediating" effect on rhubarb by alleviating the purgation property and reducing the toxicity.