Comparison of the micro-mechanism alterationIn order to elucidate the micro-mechanism alteration duringthe different extraction techniques and to investigate the extrac-tion mechanism, the untreated and treated S. baicalensis sampleswere examined by scanning electron microscopy (SEM). As shownin Fig. 4, different extraction techniques produced distinguishablemicro-mechanism alteration in the sample.In the untreated samples, the disruption of cells was seen rarely(Fig. 4a). In WaterHRE, the solvent was transferred into the sampleand the compounds were extracted by permeation and solubil-isation processed. Hence, the microstructure of the sample waslittle destructed, and a few of slight ruptures took place on thesurface of the sample (Fig. 4b). While in WaterMAE (5 min only),cells and cell walls have been partly affected by the broken effectof microwave [33], thus leading to exposure of the target to theextraction solution. Hence, the extraction yields of the four tar-get analytes obtained using the WaterMAE were higher than thoseusing the WaterHRE.