紫花地丁化学成分分析及其体外抗氧化活性考察

目的:对堇菜科堇菜属植物紫花地丁中的化学成分及其抗氧化活性进行研究。方法:取紫花地丁5 kg,加3倍量95%乙醇回流提取3次,合并提取液,过滤,减压浓缩得总浸膏,上60~100目硅胶柱色谱,用石油醚、二氯甲烷、二氯甲烷-甲醇(50∶1,10∶1,5∶1,2∶1)及甲醇洗脱,得到7个相应馏分。各部位依次运用正相硅胶柱色谱,十八烷基硅烷键合硅胶(ODS)柱色谱,LH-20型羟丙基葡聚糖凝胶(Sephadex LH-20)柱色谱和制备型高效液相色谱(HPLC)等方法进行分离纯化,得到的化合物经核磁共振波谱(NMR),质谱(MS),红外光谱(IR)等波谱学方法进行鉴定。同时,对从紫花地丁分离得到的部分化合物进行清除1,1-二苯基-2-三硝基苯肼(DPPH)自由基实验。结果:从紫花地丁95%乙醇提取物中分离得到14个化合物,分别为N-acetyl-1-ethyl ester glutamic acid(1),N-acetyl glutamic acid-1-ethyl-5-methyl ester(2),橙黄胡椒酰胺(3),rel-(2α,3β)-7-O-methylcedrusin(4),齐墩果酸(5),α-tocopherol-quinone(6),杨芽黄素(7),异莨菪亭(8),七叶内酯(9),24-ethylcholesta-4,24(28)Z-dien-3-one(10),stigmasta-4,25-dien-3-one(11),β-sitostenone(12),β-谷甾醇(13),豆甾-5-烯-3β-醇-7-酮(14)。结论:化合物2为新的天然产物,化合物1,4,6,7,10~12为首次从堇菜属植物分离得到。化合物9具有显著的抗氧化活性,化合物2,6,8具有一定的DPPH自由基清除活性。

Analysis of Chemical Constituents in Violae Herba and Investigation of Its Antioxidant Activity in Vitro

Objective: To investigate the chemical constituents and antioxidant activities of Violae Herba from the Violaceae. Method: The 5 kg of Violae Herba was refluxing extracted with 3 times the amount of 95% ethanol for three times,then the extracting solution was combined,filtrated,concentrated under vacuum to get the total extract. Seven corresponding fractions were eluted with petroleum ether,dichloromethane,dichloromethane-methanol(50∶1,10∶1,5∶1,2∶1)and methanol by silica gel column chromatography(60-100 mesh)on the total extract. Each fraction was isolated and purified by normal phase silica gel column chromatography,octadecylsilane chemically bonded silica(ODS)column chromatography,Sephadex LH-20 column chromatography and preparative high performance liquid chromatography(HPLC),respectively. The structures of the obtained compounds were identified by spectroscopic methods of nuclear magnetic resonance(NMR),mass spectroscopy(MS)and infrared spectroscopy(IR). Meanwhile,some of these compounds isolated from Violae Herba were carried on the 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging experiment. Result: Fourteen compounds were isolated from the 95% ethanol extract of Violae Herba,including N-acetyl-1-ethyl ester glutamic acid(1), N-acetyl glutamic acid-1-ethyl-5-methyl ester(2),aurantiamide(3),rel-(2α,3β)-7-O-methylcedrusin(4),oleanolic acid(5),α-tocopherol-quinone(6),tectochrysin(7),isoscopoletin(8),esculetin(9),24-ethylcholesta-4,24(28)Z-dien-3-one(10),stigmasta-4,25-dien-3-one(11),β-sitostenone(12),β-sitosterol(13),(24 R)-3β-hydroxy-ethylcholest-5-en-7-one(14).Conclusion: Compound 2 is a new natural product,compounds 1,4,6,7,10-12 are isolated from the genus Viola for the first time. Compound 9 has significant antioxidant activity,while compounds 2,6 and 8 have certain DPPH free radical scavenging activity.