Separation and purification of alkaloids from Sophora flavescens Ait. by focused microwave-assisted aqueous two-phase extraction coupled with reversed micellar extraction

• FMAATPE combining focused microwave-assisted extraction (FMAE) aqueous two-phase extraction (ATPE).
• Optimized FMAATPE conditions for extraction of alkaloids from Sophora flavescens Ait. with orthogonal test.
• Reversed micellar extraction (RME) improved further purification of alkaloids with higher recovery.
• FMAATPE coupled with RME exhibited advantages of intensifying extraction, improving demixing and removing impurities.

Based on advantages of microwave-assisted extraction (MAE), aqueous two-phase extraction (ATPE) and reversed micellar extraction (RME), a novel method of extraction and purification of alkaloids from Sophora flavescens Ait. was put forward by using focused microwave-assisted aqueous two-phase extraction (FMAATPE) coupled with the reversed micellar extraction (RME). The aqueous two-phase system (ATPS) consisted of ethanol and ammonia sulfate was used as extracting solvent, FMAATPE conditions such as the compositions of ATPS, and the extraction temperature, extraction time and solvent-to-materials ratio were optimized by orthogonal test through HPLC analysis. Then alkaloids extracted by FMAATPE were further purified with reverse micelles of sodium dodecyl benzene sulfonate/isooctane/n-octanol. The relative purity of total alkaloids in the product was improved greatly by RME from 58.30% to 88.75% (w/w), and purification recovery was higher than that of solvent extraction, ion exchange resin and macroporous adsorption resin. Moreover, the reverse micelles used could be readily recycled by adding salt and water, keeping better extraction performance with about 80% (w/w) of recovery. Thus, the proposed method is easy to adjust, operate and enlarge for better application prospect; the purity of alkaloids obtained meets the requirements of the compound drug preparation.

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