小红柳化学成分及体外抗氧化活性研究

Constituents and Antioxidant Activity in vitro of Salix microstachya var. bordensis

目的：研究小红柳的化学成分及其体外抗氧化活性。方法：采用柱色谱技术进行分离,通过光谱方法及理化性质进行结构鉴定;以常用抗氧化剂Vc和BHT为阳性对照,通过DPPH·法测定分离得到的单体化合物清除自由基的能力,并计算各单体IC50。结果：从小红柳中分离得到8个化合物,分别鉴定为：山柰酚（1）、槲皮素-3-O-β-D-葡萄糖苷（2）、鼠李素（3）、山柰酚-4＇-甲醚（4）、阿魏酸甲酯（5）、myricarin A（6）、山柰酚-7,4＇-二甲醚（7）、槲皮素（8）;在一定浓度范围内,该8个化合物的自由基清除能力与浓度呈量效关系;由IC50得出化合物1、2、6、8对DPPH·自由基清除能力相当,弱于Vc,稍强于BHT。结论：化合物1~8均为首次从该植物中分离得到;抗氧化试验说明化合物1、2、6、8具有很强抗氧化活性,均可作为有效的天然自由基清除剂。

Objective： To explore the chemical constituents of Salix microstachya var. bordensis and their antioxidant activities.Methods： Column chromatography was used for separation,NMR,UV and MS spectroscopic methods were used for structure identification. Using Vc and BHT as positive controls,free radical scavenging ability of eight components from Salix microstachya var. bordensis was determined by DPPH· method and IC50 of each compound was calculated. Results： Eight compounds were isolated and identified as kaempferol（1）,quercetin-3-O-β-D-glucoside（2）,rhamnetin（3）,kaemferol-4＇-methylether（4）,ferulic acid methyl ester（5）,myricarin A（6）,kaempferol-7,4＇-dimethylether（7） and quercetin（8）. Scavenging ability of eight compounds had dose-effect relationship with concentration in a certain concentration range; Scavenging ability on DPPH· radical of myricarin A,kaempferol,quercetin and quercetin-3-O-β-D-glucoside were equal,lower to Vc,but slightly stronger than BHT. Others were lower than BHT,and ferulic acid methyl ester was the lowest deriving from the IC50. Conclusion： Compounds 1 ~ 8 are all isolated from Salix microstachya var. bordensis for the first time. Myricarin A,kaempferol,quercetin and quercetin-3-O-β-D-glucoside,having strong antioxidant activities,can be used as effective natural free radical scavenger and have great prospects for development and utilization.