益智仁总黄酮超声辅助提取工艺优化及其抗氧化活性

为优化益智仁总黄酮的超声辅助提取工艺，通过单因素试验考察乙醇体积分数、液料比、超声时间和超声功率对总黄酮得率的影响，在单因素试验的基础上，通过Box-Behnken试验设计，获得益智仁总黄酮超声辅助提取的最佳工艺；以总抗氧化能力、清除1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl radical，DPPH）自由基能力、清除超氧阴离子自由基能力、螯合铁离子能力为指标，评价了益智仁总黄酮的抗氧化活性。结果表明：超声辅助提取益智仁总黄酮的最佳工艺条件为乙醇体积分数65%、液料比40∶1（mL/g）、超声时间35 min、超声功率360 W，在此条件下益智仁总黄酮得率为0.50%；益智仁总黄酮具有较好的抗氧化活性，总抗氧化能力、清除DPPH自由基能力、清除超氧阴离子自由基能力和螯合铁离子能力均与黄酮质量浓度表现出一定的量效关系；益智仁总黄酮清除DPPH自由基、清除超氧阴离子自由基和螯合铁离子能力的半数有效浓度（EC50）分别为（2.85±0.20）、（0.87±0.05）g/L和（2.45±0.30）g/L。

Optimization of Ultrasonic-Assisted Extraction and Antioxidant Activities of Total Flavonoids from Alpinia oxyphylla Fruits

The ultrasonic-assisted extraction of total flavonoids from Alpinia oxyphylla fruits was optimized by response
surface methodology. One-factor-at-a-time experiments were carried out to investigate the effects of ethanol concentration,
solvent-to-solid ratio, ultrasonic treatment time and power on the extraction yield of total flavonoids. This was followed
by mathematical modeling based on a Box-Behnken design and response surface analysis. Antioxidant activities of
total flavonoids from Alpinia oxyphylla fruits were evaluated by in vitro antioxidant assays: total antioxidant capacity,
1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, superoxide anion radical scavenging activity and ferrous
ion chelating ability. The results showed that the optimal extraction parameters were determined as 65%, 40:1 (mL/g), 35 min
and 360 W for ethanol concentration, solvent-to-solid ratio, ultrasonic treatment time and power, respectively. The yield
of total flavonoids from Alpinia oxyphylla fruits could be up to 0.50% under these conditions. Total antioxidant capacity,
DPPH radical scavenging activity, superoxide anion scavenging activity and ferrous ions chelating ability of total flavonoids
from Alpinia oxyphylla fruits were concentration dependent. The median effective concentrations (EC50) for DPPH radical
scavenging activity, superoxide anion scavenging activity and ferrous ion chelating ability were (2.85 ± 0.20), (0.87 ± 0.05) and
(2.45 ± 0.30) g/L respectively.