Wei Shu-Dong, Zhou Hai-Chao, Lin Yi-Ming
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005, China; E-Mails:
Int J Mol Sci. 2011 Feb 15;12(2):1146-60. doi: 10.3390/ijms12021146.
The polymeric procyanidins extracted from Acacia confusa stem bark were fractionated with a step gradient of water, methanol and acetone on a Sephadex LH-20 column. The antioxidant activity of the collected fractions was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing/antioxidant power (FRAP) assays. All fractions possessed potent antioxidant activity with the highest activity observed for fraction F9. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and reversed-phase high performance liquid chromatography (RP-HPLC) analyses suggested that the collected fractions consisted primarily of oligomeric and polymeric procyanidins, with different polymer ranges and most abundant polymer size. For each fraction, catechin and epicatechin were present as both terminal and extension units, and epicatechin was the major component in the extended chain. The mean degree of polymerization (mDP) of each fraction differed, ranging from 1.68 (fraction F2) to 17.31 (fraction F11). There was a relationship between antioxidant activity (IC50/DPPH and FRAP) and mDP (R(2) (DPPH) = 0.861, P = 0.006 and R(2) (FRAP) = 0.608, P = 0.038), respectively. However, the highest antioxidant activity of fraction (F9) was not coincident with the maximum mDP of fraction (F11).
从台湾相思树茎皮中提取的聚合原花青素，在葡聚糖LH - 20柱上采用水、甲醇和丙酮的梯度洗脱进行分离。通过2,2 - 二苯基 - 1 - 苦基肼（DPPH）自由基清除法和铁还原/抗氧化能力（FRAP）测定法研究收集馏分的抗氧化活性。所有馏分均具有较强的抗氧化活性，其中F9馏分的活性最高。基质辅助激光解吸/电离飞行时间质谱（MALDI - TOF MS）和反相高效液相色谱（RP - HPLC）分析表明，收集的馏分主要由低聚和聚合原花青素组成，具有不同的聚合物范围和最丰富的聚合物尺寸。对于每个馏分，儿茶素和表儿茶素既作为末端单元又作为延伸单元存在，并且表儿茶素是延伸链中的主要成分。每个馏分的平均聚合度（mDP）不同，范围从1.68（F2馏分）到17.31（F11馏分）。抗氧化活性（IC50/DPPH和FRAP）与mDP之间分别存在相关性（R(2)（DPPH）= 0.861，P = 0.006和R(2)（FRAP）= 0.608，P = 0.038）。然而，馏分F9的最高抗氧化活性与馏分F11的最大mDP并不一致。
