A Study On Extraction Procession Of Astragalosid IV

Extracting techniques is experimentally studied by using methods of water-extraction, alcohol-extraction, and microwave-assisted extraction (MAE) for Astragalus. According the content of Astragaloside IV that is extracted from Astragalus measured by the HPLC-ELSD method, the extracting yield is gained. And the extracting effect infected by the technical parameters of each method is discussed.Through series experiments designed according orthogonal test method, the effects of temperature, extracting time and pH of extracting solution on Astragaloside IV yield are studied in water-extraction method. The results show that the pH of extracting solution is the most effective factor. In alcohol-extraction experiment, alcohol concentration and pH of extracting solution are the main influential factors by comparing the effects of alcohol concentration and pH of extracting solution with that of alcohol dosage. In MAE experiment, the effects of microwave power, actuation time, pretreatment time, alcohol concentration, alcohol dosage and pH of extracting solution on the Astragaloside IV yield are analyzed, microwave power and actuation time are found to be remarkable influence factors. According to the orthogonal experiment results, the univariate experiments are carried out to analysis individually the main factors influencing the Astragaloside IV yield, as a result, the suitable process conditions of water-extraction, alcohol-extraction and MAE are obtained respectively. Furthermore the results of these experiments indicate that both grinding and pre-soakage can improve the Astragaloside IV yield considerably.By comparing extraction yield of the above three extraction methods, the MAE method is considered as the optimal one due to the higher extraction efficiency and composition yield as well as lower energy consumption. After the row material is grinded and pre-soaked, the extracting process include two times of extracting: in the first time, MAE extraction is adopted which is followed by alcohol extraction. Both extracting time are 20 minutes, and other conditions are selected as pH 12 of extracting solution, 60% alcohol concentration, 6 times amount of alcohol and 70W·g-1 of microwave power.