A sustainable and integrated natural surfactant mediated microwave-assisted extraction technique enhances the extraction of phytochemicals from plants

Natural surfactant mediated microwave-assisted extraction (NSM-MAE) technique was developed and performed for the simultaneous extraction of hydrophilic and hydrophobic phytochemicals from plant matrix, such as phenolic acid, coumarin, bisepoxy lignan and phenylpropanoid from Acanthopanax senticosus stems. The natural surfactant soapnut saponin (SS) ethanol solution was chosen as the best solvent for the efficient extraction of active constituents from plant matrix after screening ten different types of the surfactants. The relevant key experiment parameters during the extraction process were optimized by Box-Behnken design (BBD) and single factor test. Extraction process with the optimized relevant parameters: liquid solid ratio 43 mL/g, 0.8% (g/mL) SS, extraction time 15 min, microwave power 470 W, and system temperature 60 ℃, extraction yields of the eleutheroside E, protocatechuic acid, isofraxidin, chlorogenic acid and eleutheroside B finally reached 1658.38, 312.71, 631.62, 16,282.17 and 3215.39 μg/g, respectively. The extraction yields was 1.34 fold higher than that of conventional ethanol based ultrasound-assisted extraction (Et-UAE) method. Furthermore, ABTS and DPPH free radical scavenging ability were used to investigate effects of different extraction methods. Moreover, foam separation technique was used to enrich and recycle soapnut saponin from extraction solvents. The present study indicated that the integrated NSM-MAE method was a safe, green and effective technique for the extraction and enrichment of targeted active phytochemicals from plant matrix and this method could be considered as a novel promising extraction technique to be scaled up in the industry production.