大花罗布麻不同部位酚类物质含量及其抗氧化活性比较研究

目的：比较大花罗布麻根、茎、叶、花4 个部位中游离态和结合态酚类物质的含量和抗氧化活性的差异，并分析含量与抗氧化活性之间的相关性。方法：采用Folin-Ciocalteu法、NaNO2-Al(NO3)3法分析罗布麻的根、茎、叶、花4 个部位的游离态和结合态总多酚、总黄酮含量，采用DPPH自由基清除能力、ABTS+·清除能力和铁离子还原能力3 种方法评价其体外抗氧化能力差异。结果：大花罗布麻总酚含量次序为：叶＞根＞花＞茎，各样品间存在显著性差异（P＜0.05）。各部位游离酚、结合酚和总多酚含量分别介于3 560.19～6 273.23、13.45～22.01和3 582.2～6 286.68 mg GAE/100 g干质量，其游离态多酚占总酚含量百分比平均为99.60%；游离态黄酮、结合态黄酮和总黄酮含量分别介于1 080.30～2 488.21、9.69～28.59、1 106.81～2 516.80 mg RE/100 g 干质量，其游离态黄酮占总黄酮含量的百分比平均为98.64%。大花罗布麻叶提取物清除DPPH 自由基、ABTS+·能力和总还原力最强，抗氧化活性与总酚含量之间具有良好的线性关系（r＞0.950 0）。结论：大花罗布麻各部位中含有较丰富的酚类物质，具有较强的抗氧化活性。

Comparison of Antioxidant Activity and Phenolic Content of Different Parts of Poacynum hendersonii Woodson

Objective: The roots, stems, leaves and flowers of Poacynum hendersonii Woodson were compared for
differences in the contents of free and bound phenolics and antioxidant activity, and the correlation between phenolic content
and antioxidant activity was analyzed. Methods: The contents of free and bound phenolics were measured by Folin-Ciocalteu
assay, and the content of total flavonoids by NaNO2-Al(NO3)3 assay. The antioxidant properties were evaluated by 2,2-diphenyl-
1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical
scavenging and reducing power (FRAP, ferric reducing ability of plasma) assays. Results: The total phenolic content in different
parts of Poacynum hendersonii Woodson decreased in the following order: leaves ＞ roots ＞ flowers ＞ stems, with significant
differences among these parts (P ＜ 0.05), and the contents of free, bound and total phenolics ranged from 3 560.19 to 6 273.23,
13.45 to 22.01 and 3 582.20 to 6 286.68 mg gallic acid equivalents (GAE) per 100 g dry weight (md), respectively. The average
percent contribution of free to total phenolics was 99.60%. The contents of free, bound and total flavonoids in the roots, stems,
leaves, and flowers ranged from 1 080.3 to 2 488.21, 9.69 to 28.59 and 1 106.81 to 2 516.8 mg of rutin equivalents (RE)/100 g md
respectively. The average percent contribution of free to total flavonoids was 98.64%. The phenolic extract of the leaves showed
more significant antioxidant activity in radical scavenging and reducing power assays than those of three other parts. There was a
good linear relationship between total phenolics and antioxidant activities (r ＞ 0.950 0). Conclusion: Various parts of Poacynum
hendersonii Woodson are rich in phenolics and possess high antioxidant activity.