Optimization of Extraction Technology of Free Anthraquinones from Rheum

Objective To study the optimum extraction technology of free anthraquinones from Rheum by thermal reflux with dichloromethane.Methods The L9(34) orthogonal table was employed to optimize the extraction technology with the yields of rhein,archen and aloe-emodin as evaluation indexes.The influence factors including extraction time,the amount and concentration of sulfuric acid was investigated.Results The optimum extraction conditions for archen were as follows: Rheum powder 100 g,reflux for 2.5 h,150 mL sulfuric acid of 20 %.Conclusion Rhein,archen and aloe-emodin can be successfully extracted by this method and the cost and toxicity in extraction process both are reduced,so this method can be used for the extraction of anthraquinones from Rheum in laboratory.