Influence of extraction methods on the recovery of astragaloside IV from the roots of Astragalus mongholicus in Soxhlet- and Twisselmann-type apparatus

Abstract: Astragalus mongholicus, commonly used in Traditional Chinese Medicine (TCM), contains significant amounts of triterpene saponins – astragalosides, which possess a wide variety of pharmacological actions, including the treatment of cardiovascular and respiratory diseases. The present study was performed to develop a fast and effective extraction method of saponins from crude plant material using Twisselmann-type apparatus. Moreover, a detailed comparison between Soxhlet and Twisselmann apparatus was performed to explain the advantages and disadvantages of their applications. The content of astragaloside IV – the major saponin of A. mongholicus extracts and chosen as an extraction efficiency marker ‒ was determined by means of RP-HPLC-ELSD chromatography in an herein optimized method. Twisselmann extraction shortened its duration from 4 to 2 hours in comparison with the Soxhlet method ‒ a generally accepted method preparation for this extract. The effectiveness of both apparatus was alike (3.24 ± 0.44 mg and 3.48 ± 0.26 mg of astragaloside IV/ 4g of powdered root for 2 hours in Twisselmann and 4 hours in Soxhlet apparatus). Compared with a pharmacopoeial method, the application of Twisselmann apparatus enabled a decrease in analysis time of 50%, which is of high significance, especially for large, scaled-up industrial scale.