Optimization of the Extraction of Antioxidant Components from <i>Curculigo orchioides</i> Gaertn Rhizomes by Ultrasound-Assisted Enzymatic Extraction

This study investigated the application of ultrasound-assisted enzymatic extraction (UAEE) to obtain bioactive compounds from C. orchioides. The major natural compounds, including phenolics, alkaloids, saponins, flavonoids, and terpenoids, were identified in the extracts. Cellulase concentration, temperature, and material/solvent ratio were determined to be the main factors affecting the extraction efficiency. Using Response surface methodology (RSM), the optimal conditions were established to maximize the bioactive compounds. The major natural compounds, including phenolics, alkaloids, saponins, flavonoids, and terpenoids, were identified in the extracts. The optimal parameters included a cellulase concentration of 2.63%, an extraction time of 10 minutes, a solvent ratio of 75.36, and a temperature of 38.86°C. The total polyphenol content was 48.571 mg GAE/g DW (R²=0.9903) and the total flavonoid content was 16.664 mg QE/g DW (R²=0.9842). The antioxidant activity assessed by DPPH, ABTS, FRAP, and RP assays showed lower values than the positive controls ascorbic acid and trolox. These findings indicate that although the antioxidant potential of C. orchioides extracts is modest, they are still promising as a source of natural bioactive compounds for potential applications in functional foods and pharmaceuticals.