Supramolecular solvent-based ultrasound-assisted extraction of fangchinoline and tetrandrine from the roots of Stephaniae tetrandrae.

A supramolecular solvent (SUPRAS) based ultrasound-assisted extraction method was developed for the extraction of fangchinoline and tetrandrine from Radix Stephaniae tetrandrae. SUPRASs were prepared in aqueous solutions containing hexafluorobutanol (HFB) and alkanols for the first time. HFB was used as a coacervation agent and density-regulating agent for the SUPRAS preparation. The biosurfactants, namely hexanol, octanol, and decanol were selected as the amphiphiles. The possible mechanism of the new SUPRAS formation was studied. The hydrogen-bond and hydrophobic interactions between HFB and alkanols are the main driving forces for the new SUPRAS formation. The crucial parameters influencing the extraction yields of FAN and TET, such as the type and content of amphiphile, type and content of coacervation agent, volume of SUPRAS, ultrasound time, and extraction temperature were investigated and optimized. HFB-hexanol SUPRAS was found to be the most effective extraction solvent for the extraction of fangchinoline and tetrandrine from Stephaniae tetrandrae. Under the optimized conditions, HFB-hexanol SUPRAS showed extraction yields of 7.11 and 13.89 mg g^-1 for FAN and TET, respectively. The values were higher than those obtained with other extraction methods. The developed method has a great potential for extracting alkaloids from natural plant materials.