中文摘要：

目的研究铁皮石斛的化学成分。方法利用硅胶、凝胶柱色谱及制备高效液相色谱等方法进行分离,根据光谱数据和理化性质鉴定其结构。并利用1,1-苯基苦基苯肼（DPPH）自由基清除实验评价分得的化合物的抗氧化活性。结果从铁皮石斛的脂溶性部位分离得到了15个酚性化合物及2个二氢黄酮类化合物,分别鉴定为：N-p-香豆酰酪胺（1）,反-N-（4-羟基苯乙基）阿魏酸酰胺（2）,二氢松柏醇二氢对羟基桂皮酸酯（3）,二氢阿魏酰酪胺（4）,4-羟基-N-[2-（4-羟基苯基）乙基]苯丙酰胺（5）,丁香酸（6）,丁香醛（7）,香草酸（8）,对羟基苯丙酸（9）,对羟基桂皮酸（10）,阿魏酸（11）,对羟基苯甲酸（12）,灯盏花苷II（13）,二氢丁香苷（14）,3,5-二甲氧基-4-羟基苯基-1-O-β-D-葡萄糖苷（15）,柚皮素（16）及3′,5,5′,7-四羟基二氢黄酮（17）。其中化合物2、3、4、6、11及17具有抗氧化活性,但均弱于阳性对照抗坏血酸的活性。结论化合物1～17均为首次在铁皮石斛中分离得到,化合物的活性强弱与结构之间存在一定的相关性。

英文摘要：

OBJECTIVE To study the chemical constituents of Dendrobium candidum. METHODS The compounds were separated by column chromatography with silica gel,Sephadex LH-20,and prep-HPLC. Their structures were elucidated on the basis of spectroscopic data and physicochemical properties. The antioxidant activity of the compounds was evaluated by DPPH free radical scavenging assay. RESULTS 15 phenolic compounds and 2 flavanones were isolated and identified as paprazine （1）,moupinamide （2）,dihydroconiferyl dihydro-p-cumarate （3）,dihydroferuloyltyramine （4）,4-hydroxy-N-[2-（4-hydroxyphenyl）ethyl]benzenepropanamide （5）,syringic acid （6）,syringaldehyde （7）,vanillic acid （8）,p-hydroxy-phenylpropionic acid （9）,p-hydroxy cinnamic acid （10）,ferulic acid （11）,4-hydroxybenzoic acid （12）,erigeside II （13）,dihydrosyringin （14）,koaburaside （15）,naringenin （16） and 3＇,5,5＇,7-tetrahydroxyflavanone （17）. Compounds 2,3,4,6,11 and 17 showed medium antioxidant activity,and the activity was weaker than vitamin C. CONCLUSION All of the compounds were isolated from this plant for the first time,and the relationship between structure and activity was found.