金钗石斛中联苄类和酚酸类成分的抗氧化活性研究

 目的研究金钗石斛体积分数60%乙醇提取物中联苄类和酚酸类成分的抗氧化活性,探讨其抗氧化活性与结构的关系。方法综合运用现代色谱学和光谱学方法对金钗石斛体积分数60%乙醇提取物中的化学成分进行分离鉴定;采用1,1-苯基苦基苯肼(DPPH)自由基清除法和氧自由基清除能力法两种体外活性测试方法评价分得的16个化合物的抗氧化活性。结果从金钗石斛体积分数60%乙醇提取物中分离得到3个新的联苄类化合物和13个酚酸类化合物,将它们的结构鉴定为nobilinA(1),nobilinB(2),nobilinC(3),丁香酸(syringicacid)(4),2-羟基苯丙醇(2-hydroxyphenylpropanol)(5),香草醛(vanil-lin)(6),罗布麻宁(apocynin)(7),松柏醛(coniferylaldehyde)(8),丁香醛(syringaldehyde)(9),丁香乙酮(syringylethanone)(10),对羟基苯甲醛(p-hydroxybenzaldehyde)(11),3-羟基-4-甲氧基苯乙醇(3-hydroxy-4-methoxyphenylethanol)(12),α-羟基丁香丙酮(α-hydroxysyringylethanone)(13),二氢松柏醇(dihydroxyconiferylalcohol)(14),对羟基苯甲酸(p-hydroxybenzoicacid)(15),对羟基苯丙酸(p-hydroxyphenylpropionicacid)(16)。1-二苯基-2-苄基苯肼(DPPH)法活性测试中,化合物4的活性明显强于维生素C(VitC),化合物1,2,12,14显示出弱于VitC但强于2,6-二羟丁基对甲酚(BHT)的活性,化合物3和8只显示很弱的活性;氧自由基清除能力法(ORAC)法测试结果表明,化合物2～4,7～10,15显示出强于VitC的活性,化合物12,14,16活性较弱。结论金钗石斛中的联苄类和酚酸类化合物大多具有不同程度的抗氧化活性,活性的强弱与分子结构之间存在一定的相关性。

Studies on Antioxidant Activity of Bibenzyls and Phenolic Components from Dendrobium nobile

OBJECTIVE To study the antioxidant activity of bibenzyls and phenolic components isolated from the 60% EtOH extract of Dendrobium nobile,and discuss the structure-activity relationship.METHODS Compounds were isolated from the 60% EtOH extract of Dendrobium nobile through various chromatographic techniques and identified by spectral data.The antioxidant activity of 16 compounds was evaluated by DPPH free radical scavenging assay and oxygen radical absorbance capacity assay.RESULTS Three new bibenzyls and thirteen phenolic compounds were obtained.Their structures were characterized as nobilin A(1),nobilin B(2),nobilin C(3),syringic acid(4),2-hydroxyphenylpropanol(5),vanillin(6),apocynin(7),coniferyl aldehyde(8),syringaldehyde(9),syringylethanone(10),p-hydroxybenzaldehyde(11),3-hydroxy-4-methoxyphenylethanol(12),α-hydroxysyringylethanone(13),dihydroxyconiferyl alcohol(14),p-hydroxybenzoic acid(15),and p-hydroxyphenylpropionic acid(16),respectively.In the DPPH assay,compound 4 exhibited significant scavenging activity,compared with vitamin C.Compounds 1,2,12 and 14 showed higher activity than BHT and weaker activity than vitamin C.The activity of compounds 3 and 8 was very weak.In the ORAC assay,compound 2～4,7～10,and 15 displayed stronger peroxyl radical scavenging activity than vitamin C,and compound 12,14,16 showed weak activity.CONCLUSION Most of the bibenzyls and phenolic components exhibited antioxidant activity in different levels,and the relationship between structure and activity was found.