Karonen Maarit, Leikas Anne, Loponen Jyrki, Sinkkonen Jari, Ossipov Vladimir, Pihlaja Kalevi
Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku, FI-20014 Turku, Finland.
Phytochem Anal. 2007 Sep-Oct;18(5):378-86. doi: 10.1002/pca.992.
Mountain birch leaves contain large amounts of structurally variable polymeric proanthocyanidins. Their isolation procedure was enhanced by the addition of liquid-liquid extractions prior to column chromatography over Sephadex LH-20. Isolated polymeric proanthocyanidins were depolymerised by acid-catalysis in the presence of benzyl mercaptan or phloroglucinol in order to study their composition. The resulting degradation products, flavan-3-ols and flavan-3-ol adducts, were analysed with reversed-phase high-performance liquid chromatography using UV photodiode array detection for quantification and electrospray ionisation mass spectrometry for identification. The results showed that polymeric proanthocyanidins contained (epi)gallocatechins and (epi)catechins as the extension units and, mainly, (+)-catechin as the terminal unit. The mean degree of polymerisation was found to be 26 based on thiolysis and 31 based on phloroglucinol degradation.
高山桦树叶含有大量结构多变的聚合原花青素。在通过葡聚糖LH - 20柱色谱法之前，通过添加液 - 液萃取增强了它们的分离程序。为了研究其组成，分离出的聚合原花青素在苄基硫醇或间苯三酚存在下通过酸催化解聚。使用反相高效液相色谱法对所得降解产物黄烷 - 3 - 醇和黄烷 - 3 - 醇加合物进行分析，采用紫外光电二极管阵列检测进行定量，并采用电喷雾电离质谱法进行鉴定。结果表明，聚合原花青素含有（表）没食子儿茶素和（表）儿茶素作为延伸单元，并且主要含有（+） - 儿茶素作为末端单元。基于硫解，发现平均聚合度为26，基于间苯三酚降解为31。
