甘草药渣中黄酮类成分及其抗氧化活性的研究

Flavonoids and their anti-oxidant activities of the herb residues of Glycyrrhiza glabra L.

目的研究甘草药渣中黄酮类成分及其抗氧化活性,为其资源再利用提供依据。方法甘草药渣提取液中的黄酮成分采用硅胶、C18中压反相柱色谱和重结晶进行分离纯化,波谱分析进行结构鉴定,然后其抗氧化活性采用1,1-二苯基-2-苦肼基（DPPH）自由基清除及酪氨酸酶抑制实验来测定。结果从中分离鉴定出10个黄酮类化合物,分别为甘草查尔酮甲（1）、异甘草素（2）、甘草黄酮C（3）、甘草黄酮（4）、甘草异黄酮乙（5）、光甘草酮（6）、甘草素（7）、半甘草异黄酮B（8）、甘草异黄酮甲（9）、芒柄花素（10）。其中,化合物1、2、5、6清除DPPH自由基作用相对较强,IC50分别为27.9、61.0、18.2、26.0μg/m L;化合物1~3能较显著地抑制酪氨酸酶,IC50分别为60.3、4.9、54.9μg/m L。结论甘草药渣中仍含有多种具抗氧化活性的黄酮类化合物,应进一步开发利用。

AIM To study the flavonoids and their anti-oxidant activities of the herb residues of Glycyrrhiza glabra L. for the further application and development of them. METHODS Flavonoids from the herb residues of G. glabra were isolated by silica,ODS-C18medium-pressure column and recrystallization and identified by spectral analysis. The anti-oxidant activities of them were then evaluated by DPPH radical scavenging assay and inhibition of tyrosinase. RESULTS Ten flavonoids were isolated from these herb residues and identified as licochalcone A（ 1）,isoliquiritigenin（ 2）,licoflavone C（ 3）,licoflavone（ 4）,licoisoflavone B（ 5）,glabrone（ 6）,liquiritigenin（ 7）,semilicoisoflavone B（ 8）,licoisoflavone A（ 9）,formononetin（ 10）. Among them,compounds 1,2,5and 6 showed better DPPH radical scavenging activities,the IC50 values of which were 18. 2,26. 0,27. 9 and 60. 0μg /m L,respectively. Compounds 1- 3 could also significantly inhibit tyrosinase,the IC50 values of which were4. 9,54. 9 and 60. 3 μg / m L,respectively. CONCLUSION The herb residues of Glycyrrhiza glabra L. still contain a variety of flavonoids having anti-oxidant activities for further research.