Green extraction of propolis using SFE, UAE, and MAE: bioactive recovery and applications

Propolis is a resinous bee product rich in phenolics, flavonoids, hydroxycinnamic acids, terpenes, and other bioactive compounds with antioxidant, antimicrobial, anti-inflammatory, and immunomodulatory activities. Conventional extraction methods such as maceration and Soxhlet extraction are widely used but are limited by long extraction time, high solvent consumption, poor selectivity, and possible degradation of thermosensitive compounds. This review critically evaluates three major green extraction technologies for propolis: supercritical fluid extraction (SFE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE). SFE improves selectivity through pressure- and temperature-dependent CO2 solvent density, with reported yields ranging from 1.32% to 53.5% and flavonoid recovery up to 60.11 mg QE/g. UAE enhances mass transfer through acoustic cavitation, producing total phenolic contents up to 459.92 mg GAE/g, flavonoid contents up to 519.77 mg QE/g, and antioxidant activity increases up to 95.55% compared with maceration. MAE promotes rapid internal heating and matrix disruption, achieving extraction yields up to 73.84% and total polyphenols of 81.78 mg GAE/g. Despite these advantages, scalability, energy demand, solvent optimization, propolis variability, and bioactive stability remain key challenges. Future research should integrate pretreatment, hybrid extraction, encapsulation, and standardized green metrics to support industrial application.