Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, Padova 35121, Italy.
Molecules. 2012 Feb 8;17(2):1686-97. doi: 10.3390/molecules17021686.
The bark of several coniferous species, a waste product of the timber industry, contains significant amounts of natural antioxidants. In our ongoing studies of Nepalese medicinal plants, we examined the bark from Abies spectabilis as the starting material for extracting antioxidant compounds. In vitro antioxidant activity evaluated by means of three antioxidant methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), Briggs-Rauscher oscillating reaction (BR) and Trolox Equivalent Antioxidant Capacity (TEAC) and total phenol contents with the Folin-Ciocalteau reagent; the ferrous iron chelating capacity was also assessed. The methanol extract of A. spectabilis showed significant antioxidant activity and polyphenol contents (IC(50) 4.13 µg/mL, 0.20 μg/mL eq. resorcinol, 4.22 mM eq. Trolox, 3.9 µg/g eq. gallic Acid in the DPPH, BR, TEAC and Folin-Ciocalteau tests, respectively) and weak Fe(2+) chelating capacity. Phytochemical studies were also carried out with 1D- and 2D NMR experiments and DI-ESI-MS, HPLC-DAD and LC-MSn measurements. Oligomeric C-type proanthocyanidins, mainly trimeric gallocatechin derivatives, were the most abundant compounds (16% of extract expressed as procyanindin B1). Gallocatechin oligomers (up to six units) and prodelphynidin-gallocatechin polymers were also identified in the extract. Prodelphynidin B4, cyclograndisolide and trans-docosanil ferulate were also isolated and characterized by NMR and MS spectroscopy.
几种针叶树的树皮，木材工业的一种废料，含有大量的天然抗氧化剂。在我们对尼泊尔药用植物的持续研究中，我们以Abies spectabilis 的树皮作为提取抗氧化化合物的起始材料。通过三种抗氧化方法，即 2,2-二苯基-1-苦基肼基（DPPH）、Briggs-Rauscher 振荡反应（BR）和 Trolox 等效抗氧化能力（TEAC）和 Folin-Ciocalteau 试剂测定总酚含量，评估了体外抗氧化活性；还评估了亚铁离子螯合能力。Abies spectabilis 的甲醇提取物显示出显著的抗氧化活性和多酚含量（DPPH 中的 IC50 为 4.13 µg/mL、0.20 µg/mL 间苯二酚当量、4.22 mM Trolox 当量、3.9 µg/g 没食子酸当量，BR、TEAC 和 Folin-Ciocalteau 试验）和较弱的 Fe（2+）螯合能力。还进行了 1D 和 2D NMR 实验以及 DI-ESI-MS、HPLC-DAD 和 LC-MSn 测量的植物化学研究。低聚 C 型原花青素，主要是三聚没食子酰基儿茶素衍生物，是最丰富的化合物（以原花青素 B1 表示，提取物的 16%）。在提取物中还鉴定了没食子酰基寡聚物（多达六个单元）和原儿茶素-没食子酰基聚合物。还通过 NMR 和 MS 光谱学分离和表征了原儿茶素 B4、环格兰地二醇和反式二十二烷酰基阿魏酸。
