核桃楸单宁提取及其抗氧化性

Extraction and Antioxidant Activity of Tannic in Juglans mandshurica Maxim

采用超声法提取核桃楸单宁,紫外分光光度法测定单宁含量。通过正交试验法考察丙酮体积分数、超声温度、超声时间及料液比等4个因素对超声法提取核桃楸单宁的影响,并得出最佳提取条件。核桃楸外果皮单宁最佳提取条件为:丙酮体积分数40%、超声温度40℃、超声时间40 min、料液比1∶15。核桃楸叶单宁最佳提取条件为:丙酮体积分数50%、超声温度60℃、超声时间30 min、料液比1∶20。核桃楸外果皮及叶单宁对羟基自由基、亚硝酸根离子及超氧阴离子均有较强的清除能力。核桃楸叶单宁对三种自由基的清除能力整体上强于核桃楸外果皮单宁。这表明核桃楸单宁具有较强的抗氧化性,是很好的天然抗氧化剂,具有潜在的药用价值。

Juglans mandshurica Maxim. tannins was extracted by ultrasonic method. Tannins content was determined by UV spectrophotometry. The effects of the volume fraction of acetone, ultrasonic temperature, ultrasonic time, and ratio of material to liquid on tannins were evaluated by orthogonal test method in the ultrasonic experiment. The optimal extraction conditions for the tannins in green peel of J. mandshurica were the volume fraction of acetone of 40%, ultrasonic temperature of 40℃, extraction time of 30 min, and solid-liquid ratio of 1：15. The optimal extraction conditions for the tannins in leaves of J. mandshurica were the volume the fraction of acetone of 50%, ultrasonic temperature of 60℃, extraction time of 40 min, and solid-liquid ratio of 1：20. The tannins in both green peel and leaves had excellent scavenging capacity for hydroxyl radical, nitrite ions and superoxide anion. The ability of scavenging three kinds of free radicals of the tannins in leaves was stronger than that of the green peel. J. mandshurica tannins had strong antioxidation, and the tannins was with potential pharmaceutical value as a good natural antioxidant.