College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
PLoS One. 2018 Aug 14;13(8):e0202368. doi: 10.1371/journal.pone.0202368. eCollection 2018.
Ultrasonic-assisted extraction (UAE), using aqueous ethanol as the solvent, was firstly applied to extract phenolic compounds from Terminalia chebula Retz. fruits (T. chebula fruits). In this study, ethanol concentration (%), ultrasonic intensity (W/cm2), particle diameter (mm), extraction temperature (°C), ultrasonic time (min), liquid-solid ratio (mL/g) and extraction cycle were investigated by single-factor experiment and then optimized using a Box-Behnken design. The optimized result for UAE was 68% ethanol concentration, ultrasonic intensity of 3.6 W/cm2, solid-liquid ratio of 23 mg/mL, particle size of 0.18 mm and ultrasonic time of 20 min for 2 times at 70 °C. The yield of total phenolic was 448.7 ± 2.15 mg GAE/g DW under the above optimum conditions, which agreed with the predicted value (447.8 mg GAE/g DW). Compared to conventional solvent extraction (CSE), UAE extracts showed excellent DPPH radical, DPPH, ABTS scavenging activities and reducing power in a dose-dependent manner, and better than that of CSE extracts. Additionally, the extract of the T. chebula fruits was analyzed by HPLC-ESI/MS. In summary, UAE could effectively extract phenolic compounds from T. chebula fruits. In addition, the extract could be used as a potential source of natural antioxidants.
超声辅助提取 (UAE) 法，使用水乙醇作为溶剂，首次应用于从诃子果实（Terminalia chebula Retz.）中提取酚类化合物。本研究通过单因素实验考察了乙醇浓度（%）、超声强度（W/cm2）、粒径（mm）、提取温度（°C）、超声时间（min）、液固比（mL/g）和提取次数对提取的影响，然后采用 Box-Behnken 设计对其进行优化。UAE 的优化结果为 68%乙醇浓度、超声强度 3.6 W/cm2、固液比 23 mg/mL、粒径 0.18 mm、超声时间 20 min，2 次，70 °C。在此最佳条件下，总酚的得率为 448.7±2.15 mg GAE/g DW，与预测值（447.8 mg GAE/g DW）相符。与传统溶剂提取（CSE）相比，UAE 提取物对 DPPH 自由基、DPPH、ABTS 清除活性和还原能力具有优异的剂量依赖性，且优于 CSE 提取物。此外，对诃子果实提取物进行了 HPLC-ESI/MS 分析。综上所述，UAE 可以有效地从诃子果实中提取酚类化合物。此外，该提取物可作为天然抗氧化剂的潜在来源。
