Coaxial Oil-Polymer-Salt Three-Liquid-Phase Centrifugal Platform for the Extraction of the Active Ingredients From the Natural Products.

Introduction: Platycladus orientalis (L.) Franco is a unique tree species in China with a long cultivation history and diverse medicinal values. Its dried branches and leaves, called Platycladi Cacumen (PC), contain bioactive compounds. However, conventional extraction methods such as leaching or steam distillation are often associated with high consumption of reagents, time, and energy.

Objectives: This study aims to develop an efficient and environmentally friendly approach for extracting flavonoids from PC by integrating the "oil-polymer-salt" three-liquid-phase system (OPS-TLPS) with coaxial liquid centrifugal technology.

Material and methods: The OPs-TLPS was constructed using di(2-ethylhexyl) phosphate (D2EHPA), polyethylene glycol (PEG), and sodium citrate. During the study, a stable OPs-TLPS was screened by varying the phase-forming substances of the salts and oil-phase reagents, and the effects of three-phase mass fraction and reaction conditions on the extraction of active components from PC were investigated.

Results: The D2EHPA-PEG-sodium citrate system demonstrated high stability and efficiency for flavonoid extraction. Key factors, such as D2EHPA concentration, mass fractions of PEG and sodium citrate, pH, and centrifugal time, significantly influenced yield. After 2 h of extraction, over 50% of flavonoids were successfully partitioned into the oil and PEG phases. The integration of OPS-TLPS with coaxial centrifugation notably reduced organic solvent usage and improved extraction efficiency, offering a more automated and greener alternative to conventional techniques for isolating natural products.

Conclusion: This method provides a novel, sustainable, and efficient strategy for extracting flavonoids from Platycladi Cacumen, with potential applications in natural product extraction.