Evaluation of the Antioxidant Activity of the Extracts from Eucommia Male Flower in vitro | 杜仲雄花提取物的体外抗氧化活性评价

Chinese. 以杜仲雄花乙醇提取物的石油醚萃取相、乙酸乙酯萃取相、正丁醇萃取相和水相（萃余相）为研究对象，在测定各相总酚含量的基础上，选用DPPH自由基清除率、羟自由基清除率、还原力和抗脂质过氧化活性4项指标评价杜仲雄花各萃取（余）相的抗氧化活性，并与抗氧化剂BHT和VC进行比较。结果表明：杜仲雄花中含有大量的酚类化合物，其中乙酸乙酯相（393．47mg・g-1）和正丁醇相（287．33mg・g-1）中的总酚含量显著高于石油醚相（105．42mg・g-1）和水相（114．74mg・g-1），对DPPH自由基的清除率分别为91．55％和80．32％，接近于BHT和VC；正丁醇相对羟自由基清除率较高（80．47％）；乙酸乙酯相的还原力高于BHT和VC；乙酸乙酯相、正丁醇相和水相的抗脂质过氧化活性显著高于VC。杜仲雄花提取物的还原力、DPPH自由基清除率和抗脂质过氧化活性与其总酚含量呈显著正相关（R2〉0．9），与萃取（余）相的质量浓度呈明显的量效关系，这说明杜仲雄花具有较强的抗氧化活性，可作为进一步生产保健品的原料。

English. The male flowers of Eucommia ulmoides were extracted by the solvents with different polarities, namely, petroleum ether, ethyl acetate, n-butanol, and water. The contents of total phenols in the obtained extracts were measured, and their antioxidant activities were examined in vitro and compared with those of BHT and VC, which were the two conventional reductants, from the aspects of scavenging rate of DPPH and hydroxyl free radicals, reducing power, and anti-lipid per-oxidation activity, respectively. The results indicated that Eucommia male flower was rich in phenols. The content of phenols in ethyl acetate extract （EE） （393.47 mg・g-1） and n-butanol extract （BE） （287.33 mg・g-1） were higher than those in water extract （WE） （114.74 tug・g-l） and petroleum extract （PE） （105.42 mg・g-1）. The rates of scavenging DPPH free radical of the EE and BE were 91.55% and 80. 32% , respectively, close to those of BHT and VC. The rate of scavenging hydroxyl free radical of BE was relatively higher （80. 47% ） , while the reducing power of EE was higher than those of BHT and VC. The activities of anti-lipid per-oxidation of EE, BE and WE were higher than that of VC. The reducing power, rate of scavenging DPPH free radical and activity of anti-lipid per-oxidation of the extracts were positively correlated to the content of total phenols （R2 〉 0.9）, and exhibited significant concentration dependent effect. The relatively higher antioxidant activity of Eucommia male flower demonstrated that it could be developed as a health care beverage.