Liposome-integrated ultrasound coupling subcritical water extraction for enhanced the efficiency and stability of Phyllanthus emblica polyphenols

Ultrasound coupling subcritical water extraction (USWE) was developed to extract polyphenols from Phyllanthus emblica pomace (PPEPs), and extraction parameters affecting the yield of PPEPs were systematically optimized. USWE was comprehensively evaluated in terms of extraction parameters, yield, antioxidant capacity, major bioactive components, and infrared characteristics of PPEPs, and compared with four other extraction methods. Microstructural changes in the pomace were examined using scanning electron microscopy (SEM) to elucidate the interactions between the extraction process and the plant matrix. Finally, to address the issues of the instability of PPEPs and their low bioavailability, liposomal encapsulation was performed and the physicochemical properties were evaluated. Results demonstrated that the yield of PPEPs from USWE was 1.8-fold and 1.35-fold higher than those from solvent extraction (SE) and subcritical water extraction (SWE), respectively. Furthermore, PPEPs from USWE exhibited the strongest antioxidant activity and higher levels of six major bioactive compounds. SEM analysis revealed a significant increase in porosity and enlarged pores in USWE-treated pomace. Additionally, Phyllanthus emblica polyphenol liposomes (PPEPL) were prepared by thin-film dispersion technique. PPEPL showed a high encapsulation efficiency of 83.07 ± 0.09 % and retained structural integrity after 4 weeks of storage at 4 °C. PPEPL exhibited enhanced antioxidant activity compared to free PPEPs. The IC₅₀ values for scavenging DPPH·, ABTS·⁺, and hydroxyl radicals were 3.2-, 3.3-, and 1.6-fold lower, respectively. In summary, integrating USWE with liposome technology provides an efficient strategy for obtaining stable, high-quality bioactive PPEPs.