Study on Optimization of the Extraction Process of Total Flavonoids from Yao Medicine <i>Gnetum</i> <i>p</i><i>arvifolium</i> and Their Antioxidant Activity

Objective: To optimize the extraction protocol for total flavonoids from Gnetum parvifolium, determine their content, and investigate their in vitro antioxidant activity. Methods: Using rutin as a standard, key influencing factors were identified through single-factor experiments. An orthogonal experimental design was then employed to establish the optimal extraction protocol for total flavonoids from Gnetum parvifolium. The in vitro antioxidant activity was evaluated via a DPPH radical scavenging assay. Results: Scientific analysis of the experimental data indicated that the optimal conditions were ultrasound-assisted extraction with 90% ethanol as the solvent, a sample-to-solvent ratio of 1:60 (w/v), and a total of three extraction cycles. Under these conditions, the highest extraction yield of total flavonoids from Gnetum parvifolium was achieved, reaching 47.79 mg/mL. Moreover, the Gnetum parvifolium total flavonoid extract demonstrated significant radical scavenging activity, with a DPPH radical scavenging rate of 79% in the concentration range of 0.6 - 3.0 μg/mL. Conclusion: This study provides a scientific basis for the further extraction, utilization, and development of total flavonoids from Gnetum parvifolium.