The Research Of Subcritical Water Extraction Anthraquinone Derivatives From Rheum

Rheum,as a traditional Chinese medicine,has been widely used in medicine,food,health products and other industries.So extraction and separation of anthraquinone derivatives get more and more attention.Subcritical water extraction,as an envirmentally friendly green and saving method,is a kind of new extraction method developed recently.HPLC as the determination method,aloe-emodin,rhein,emodin,chrysophanol and physcion as evaluation index,external standard method is used to calculate yield of five ingredients.Different extraction methods were compared according to yield of each ingredient.This dissertation consists of five Chapters.Chapter 1 briefly described rheum and its active ingredients,the application of subcritical water extraction and significance of this dissertation.In Chapter 2,we studied that subcritical water extracted rheum anthraquinones derivative under the condition of different temperatures,time and solid-liquid ratio,and comparison with conventional organic solvent extraction and acid hydrolysis organic solvent extraction method.And optimization of subcritical water extraction craft by Box-Behnken design of response surface methodology,obtained optimum parameters: Extraction time was13.4 min,solid-liquid ratio was 1: 12.5 g/mL,and extraction temperature was 255 ?.In Chapter 3,we discussed characteristics of acidic subcritical water under the condition of different acidic concentration,obtained optimum condition: Extraction time was 40 min,concentration of sulfuric acid was 0.06 mol/L,and temperature was 180 ?.Yield of total anthraquinone was 1.15 times of subcritical water extraction,the results showed that a little sulfuric acid can increase the total yield of anthraquinone.In Chapter 4,we investigated the influence of ultrasound power,ultrasound time,solid-liquid ratio and extraction temperature on yield by the ultrasound enhanced subcritical water extraction technology,obtained optimum condition: Ultrasound power was 120 W,ultrasound time was 5 min,solid-liquid ratio was 1: 8 g/mL and temperature was 250 ?.Yield of total anthraquinone was 1.15 times of subcritical water extraction,the results showed that this technology can bring down extraction temperature,reduce the amount of solvent and increased yield of active ingredient.Chapter 5 is the summation of this dissertation.