【摘要】 对沱茶(Camelliasinensisvar.assamica)的水提取物、5 0 %甲醇提取物、甲醇提取物进行了DPPH自由基清除作用的研究,实验结果表明,水提取物和5 0 %甲醇提取物均具有较强的清除自由基作用,其半数抑制率(IC50 )分别为6 .0 7μg/mL和5 .0 1μg/mL ,而甲醇提取物清除自由基作用的活性则较弱,其半数抑制率(IC50 )为39.6 3μg/mL。利用层析等手段分别从抗自由基活性较强的水提取物的甲醇可溶部分分离获得了2 0种化合物,其中,10种化合物( 2、5、6、11、12、13、16、17、18、19)为首次从该植物中得到的化合物;DPPH自由基清除活性研究结果表明,其中化合物( 1、4、7、9、10、12、14、18)的活性强于阳性对照品抗坏血酸和咖啡酸。比较分析化合物的结构与其活性的关系,发现结构中苯环上有邻位羟基的化合物其清除自由基的活性较强,而且羟基越多活性越强更多还原

【Abstract】 The anti-free radical compounds in Tuocha(Camellia sinenses var.assamica)were extracted by water,50% MeOH and MeOH successively.The IC 50 of the anti-free radical activities of the extract of water and 50% MeOH are 6.07 μg/mL and 5.01 μg/mL,respectively,whereas the IC 50 of the anti-free radical activity of the extract of MeOH is 39.63 μg/mL.The extract of water was further fractionated by MeOH,20 compounds were obtained from the methanol solvable fraction,by chromatographic methods.Ten of them(Compound 2,5,6,11,12,13,16,17,18,19) were firstly found in Tuocha.The anti-free radical activities of eight compounds(Compound 1,4,7,9,10,12,14,18)are higher than those of positive controls,L-ascorbic acid and caffeic acid.It is found that the compounds possessing more hydroxyl groups on the benzene ring are more active than those possessing hydroxyl groups.更多还原