Microwave-Assisted Extraction for Saponins and Antioxidant Capacity from Xao Tam Phan (Paramignya trimera) Root

The aim of this study was to determine the optimal microwave-assisted extraction (MAE) parameters for saponins and antioxidant capacity from the P. trimera root. The optimal MAE parameters were found to be 100% methanol, extraction time of 40 min and ratio of solvent to sample of 100 mL/g. Saponin content, saponin extraction efficiency, ABTS radical scavenging capacity, DPPH radical scavenging capacity, cupric ion reducing antioxidant capacity, and ferric reducing antioxidant power of the P. trimera root achieved under these parameters were 520.5 mg escin equivalents (EE)/g dried sample, 62.6%, 215.3, 93.2, 24.7, 121.7 mg trolox equivalents (TE)/g dried sample, respectively, which were higher than predicted values (488.8 mg EE/g dried sample, 58.8%, 213.7, 89.5, 24.0, 115.8 mg TE/g dried sample, respectively). Therefore, the optimal MAE parameters of 100% methanol, 40 min and 100 mL/g are recommended for obtaining saponin-enriched extracts from the P. trimera root for potential application in the food industry. Practical Application This study indicated that methanol concentration had the highest effect on the extractability of saponins and antioxidant capacity from P. trimera root, followed by ratio of solvent to sample and extraction time. Therefore, the application of the optimized MAE parameters allows obtaining the highest saponin yield as well as the greatest antioxidant capacity from P. trimera root for further investigation and application.