中文摘要：

以梯度提取的方法对硬枝树花进行石油醚（30–60）、二氯甲烷、乙酸乙酯提取,浸膏经过色谱柱层析分离纯化得到6个单体化合物,分别为松萝酸（1）、黑茶溃素（2）、巴尔巴地衣酸（3）、去甲环萝酸（4）、地弗地衣酸（5）、藻纹苔酸（6）,并且都是首次从硬枝树花中分离得到。通过对清除DPPH？和ABTS？＋能力的测定,对这6个化合物体外抗氧化活性进行评价。结果表明：藻纹苔酸在检测浓度范围内的？DPPH的清除率和终浓度呈现一定的量效关系,在55μmol/L时,藻纹苔酸的清除率为57.05%（P〈0.01）。黑茶溃素、巴尔巴地衣酸、去甲环萝酸在13.75–55μmol/L检测浓度范围内的DPPH自由基清除率与终浓度呈量效关系。松萝酸对DPPH？的清除能力较强,在3.4375μmol/L及27.5μmol/L时,DPPH自由基清除率达到74.78%（P〈0.01）及74.82%（P〈0.01）,接近对照组BHT浓度为55μmol/L的清除率。地弗地衣酸、藻纹苔酸、巴尔巴地衣酸的ABTS？＋自由基清除率与终浓度呈现一定的量效关系,在浓度为55μmol/L时,地弗地衣酸ABTS？＋自由基清除率为50.79%（P〈0.01）,藻纹苔酸为44.53%（P〈0.01）,巴尔巴地衣酸为44.34%（P〈0.01）,在13.75–55μmol/L浓度范围内,黑茶溃素ABTS？＋自由基的清除率随着浓度的增大而逐渐增大。硬枝树花中含有多样的苯骈呋喃类和缩酚酸类化合物及其衍生物,是具有开发利用潜力的抗氧化剂资源。

英文摘要：

The powder of Ramalina conduplicans thallus were extracted by petroleum ether（30–60）, dichloromethane and ethyl acetate. Six compounds were isolated and identified, they were usnic acid（1）, atranorin（2）, barbatic acid（3）, evernic acid（4）,diffractaic acid（5） and salazinic acid（6）. They were all for the first time found from Ramalina conduplicans. The antioxidant ac‐tivity of the six compounds were assessed based on the ability to scavenge DPPH and ABTS free radicals in vitro. The result showed that there was a dosage‐dependent effect between DPPH·removal effect and mass concentration of salazinic acid in the test concentration range. In 55μmol/L, the clearance rate of salazinic acid is 57.05%. In 13.75–55μmol/L, there was a dos‐age‐dependent effect between DPPH·removal effect and mass concentration of atranorin, barbatic acid and evernic acid. DPPH·removal ability of usnic acid is better. There was a dosage‐dependent effect between ABTS·＋ radical scavenging effect and mass concentration of diffractaic acid, salazinic acid and barbatic acid. When the concentration is 55μmol/L, ABTS·＋ free radical clearance rate of diffractaic acid is 50.79%, that of salazinic acid is 44.53%, and that of barbatic acid is 44.34%. In 13.75–55μmol/L, there was a dosage‐dependent effect between ABTS·＋ free radical clearance rate and mass concentration of atranorin. There are benzofuranone, depsides and its derivatives in Ramalina conduplicans, so the lichen can be developed an important source of potential antioxidants.