Hop (Humulus lupulus L.) proanthocyanidins characterized by mass spectrometry, acid catalysis, and gel permeation chromatography.
Hop (Humulus lupulus L.) proanthocyanidins characterized by mass spectrometry, acid catalysis, and gel permeation chromatography.
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DOI：
10.1021/jf0340409
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发表时间：
2003-06
影响因子：
6.1
通讯作者：
Alan W. Taylor;E. Barofsky;J. Kennedy;M. Deinzer
中科院分区：
文献类型：
--
作者：
Alan W. Taylor;E. Barofsky;J. Kennedy;M. Deinzer
从啤酒花(Humulus lupulus L.cv.)威拉米特)进行Sephadex LH-20柱层析，使用甲醇、水和丙酮的阶梯梯度。采用酸催化、电喷雾电离和基质辅助激光解吸电离飞行时间质谱仪(MALDI-TOF-MS)和凝胶渗透色谱(GPC)对产物进行分析。原花青素以儿茶素和表儿茶素为单体，以末端和延伸单元形式存在。表没食子儿茶素为延伸单位。粗原花青素的平均聚合度(MDP)为7.8，但七聚体是整个图谱中可见的最大齐聚物。在最后一次洗脱的组分(MDP=22.2)中，MALDI-TOF-MS检测到了大至20-MERS的聚合物，证明了预先分离在改善MS检测方面的有效性。GPC数据与酸催化结果有很好的相关性，证实了MS没有检测到的大分子聚合物的存在。
Proanthocyanidins extracted from hops (Humulus lupulus L. cv. Willamette) were subjected to Sephadex LH-20 column chromatography using a step gradient of methanol, water, and acetone. The resulting fractions were analyzed by acid catalysis, electrospray ionization and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and gel permeation chromatography (GPC). The proanthocyanidins contained catechin and epicatechin as monomers and as terminal and extension units. Epigallocatechin was found as extension units. The mean degree of polymerization (mDP) of the crude proanthocyanidins was 7.8, but heptamers were the largest oligomers visible in mass spectra of the whole. In the last-eluted fraction (mDP = 22.2), polymers as large as 20-mers were detected by MALDI-TOF-MS, demonstrating the effectiveness of prior separation in improving MS detection. GPC data correlated well with acid catalysis results, confirming the presence of large polymers that were not detected by MS.