Optimization of extract conditions for emodin from Chinese rhubarb

In this experiment,the yield of emodin was determined by UV spectrophotometry.Taking yields of the pure emodin as a reference,benzene,the extract solvent of emodin,was initially identified by using the single-factor method.Then,the optimum extraction condition was selected with the orthogonal design,and levels(such as the dosage of solvent,dosage of acid,temperature and time) of extraction technology on the yield of emodin were studied.As a result,the best extracting conditions were as follows: the weight of Chinese rhubarb powder: benzene: 20% sulphuric acid=1∶6∶1(m∶v∶v),then percolated 3 times for 3 hours at 65 ℃.Under this condition,we could get the highest content of emodin.