An eco-friendly extraction and purification method of nuciferine from Folium nelumbinis with p-sulfonatocalix[6]arenes

Introduction Folium nelumbinis is used as vegetable, functional food and herbal medicine in Asia. p-Sulfonatocalix[6]arene (SC6A) is a water-soluble supramolecular macrocycle and has never been applied to the extraction of herbal products. Objective In this study, SC6A-assisted extraction of nuciferine from Folium nelumbinis has been carried out to develop an eco-friendly extraction process with high extraction efficacy and easy operation. Methods Single-factor experiments were adopted to obtain the optimal conditions for the SC6A-assisted extraction of nuciferine from Folium nelumbinis, and then nuciferine and SC6A were separated easily by one-step alkalization. The host-guest complexes between nuciferine and SC6A were analyzed by competitive fluorescence titration, DSC, FT-IR and H-1-NMR. Results The optimal SC6A/Folium nelumbinis/solution ratio for extraction was 0.4:1:20 (g/g/mL), with a granulometric fraction below 180 mu m and an extraction time of 1 h with soaking. The purity and recovery of nuciferine extracted with SC6A were increased 29.24 and 35.73 times compared with extraction with aqueous solution, respectively. Moreover, a good reusability of SC6A in the extraction of nuciferine was demonstrated. Competitive fluorescence titration, DSC, FT-IR and H-1-NMR characterization indicated that SC6A could form host-guest complexes with nuciferine at a ratio of 1:1. Conclusion The study provided an eco-friendly, safe and effective nuciferine extraction method, which can be used for the development of nutrition supplements containing nuciferine.