Sustainable Mechanochemical-Assisted Extraction of Active Saponins from Plants with Solid Acid and Alkalis

Saponins, as a kind of glycoside with abundant activity, exist in large quantities in plants. With the development of green chemistry and simpler cost-effective processes, a sustainable mechanochemical-assisted extraction (MCAE) method with edible solid acid and alkalis was developed for eco-friendly extraction of four saponins from Panax ginseng C. A. Meyer (ginseng). The factors influencing MCAE efficiency were optimized by single-factor experiments and the response surface methodology. The optimal MCAE process for saponins was to mill ginseng with malic acid (195.00 mg/g) and sodium carbonate (100.00 mg/g) for 6 min and extract with 28 mL of water per 1 g of ginseng powder for 5 min. Additionally, scanning electron microscopy, particle size analyzer, Fourier transform infrared spectrometer, X-ray diffraction, and mass spectrometry have demonstrated the possible extraction mechanism and effectiveness of the mechanochemical composites. Furthermore, the greenness profile was evaluated by the CHEM21 Toolkit, Analytical Eco-scale, Green Analytical Procedure Index (GAPI), and Analytical GREEnness (AGREEprep) metric, which demonstrated that this research provides a green, safe, and efficient saponin extraction method and shows the potential of the MCAE in green sustainable extraction of bioactive compounds from natural products.