蓝莓花、茎、叶酚类物质含量及抗氧化活性比较

比较蓝莓花、嫩茎、嫩叶及老叶总多酚、总黄酮、原花青素的含量,并研究其抗氧化性能差异。结果表明:嫩叶中总多酚含量最高,为43.77 mg GAE/g(以干质量计,下同),分别是花、嫩茎和老叶的3.45、1.42、1.12倍;老叶中总黄酮、原花青素含量最高,为68.01 mg RE/g、23.29 mg CAE/g,分别是花的2.57倍和4.61倍、嫩茎的1.79倍和1.23倍、嫩叶的1.03倍和1.98倍。抗氧化性能中,老叶的铁还原能力最大,其次是嫩茎和花,嫩叶较差;清除·OH的能力为嫩茎嫩叶花老叶;清除DPPH自由基能力和总抗氧化能力均为嫩茎嫩叶老叶花甲醇提取物,均高于对照品;蓝莓各部分提取物对DPPH自由基的清除能力最强,总抗氧化能力次之,清除·OH能力和铁还原能力较差。

Comparison of Antioxidant Activity and Phenolic Contents of Blueberry Flowers,Stems and Leaves

Total phenolic content (TPC), total flavonoid content (TFC) and total proanthocyanin content (TAC) were determined in blueberry flowers, tender stems, tender leaves and old leaves. Antioxidant activities of acidified methanol extracts from different parts of blueberry were evaluated by ferric reducing antioxidant power (FRAP) and hydrolxyl, DPPH and ABTS+ free radicals scavenging capacity assays. Results indicated that tender leaves contained the highest level of TPC (43.77 mg gallic acid/g md), which was increased by 3.45, 1.42 and 1.12 folds as compared to flowers, tender stems and old leaves, respectively. Old leaves contained the highest levels of TFC (68.01 mg rutin/g md) and TAC (23.29 mg catechinic acid/g md), which were 2.57 and 4.61, 1.79 and 1.23, and 1.03 and 1.98 folds higher than those in flowers, tender stems, and tender leaves, respectively. The FRAP activity of the extract from old leaves was the highest, followed by tender stems, flowers, and tender leaves. The hydroxyl radical scavenging activity was in the following order: tender stems > tender leaves > flowers > old leaves. Both the DPPH radical scavenging capability and total antioxidant capacity (TAC) were in the following order: tender stems > tender leaves > old leaves > flowers > VC. In summary, the DPPH radical scavenging was the strongest of the antioxidant activities for all the blueberry extracts, followed by TAC, and their antioxidant activities were the weakest in terms of hydroxyl radical scavenging capacity and FRAP activity.