明日叶的茎与叶主要抗氧化成分含量及抗氧化性比较

Comparison of antioxidant content and oxidation resistance of stems and leaves from Angelica keiskei Koidzmi

以明日叶茎杆与叶子为研究对象,在测定其乙醇提取物总酚酸及总黄酮含量的基础上,以芦丁为阳性对照,测定其乙醇提取物总抗氧化能力,铁离子还原/抗氧化力,以及对超氧阴离子自由基、羟基自由基、DPPH有机自由基的清除作用,并对茎杆与叶子乙醇提取物进行抗氧化活性比较。结果表明:叶乙醇提取物总酚酸和总黄酮的含量分别是茎乙醇提取物的2.2倍和5.2倍。在总黄酮质量浓度相同的条件下,叶乙醇提取物和茎乙醇提取物的抗氧化活性均与其总黄酮质量浓度呈正相关,且叶乙醇提取物的抗氧化性大于茎乙醇提取物。与芦丁相比较,芦丁对羟基自由基的清除能力大于叶乙醇提取物,其他抗氧化活性均小于叶乙醇提取物而大于茎乙醇提取物。结果表明,明日叶的叶乙醇提取物可以作为一种新型有效的天然抗氧化物质进行开发利用。

The contents of total phenols and total flavonoids of stem and leaf ethanol extracts from Angelica keiskei Koidzmi was determined. Taken Rutin as the positive control, total antioxidant capacity, iron ion reduction/ antioxi- dant capacity were investigated, the scavenging capability against superoxide anion free radicals, hydroxyl free radi- cals and DPPH free radicals were determined. The different antioxidant activities between stem ethanol extracts and leaf ethanol extracts were evaluated. Results indicated that total phenols and total flavonoids in leaves ethanol extracts were respectively 2.2 folds and 5.2 folds of stem ethanol extracts. Under the same conditions, the concentration of to- tal flavonoids, antioxidant activities of the ethanol extracts of leaves and stems were positive correlated with the mass concentration of total flavonoids. The antioxidant activities of leaves ethanol extracts were significantly higher than stem ethanol extracts. Compared with rutin, scavenging capability of rutin against hydroxyl free radicals were greater than leaves ethanol extracts, but other antioxidation activities of rutin were lower than the leaves ethanol extracts and higher than the stem ethanol extracts. Results showed that leaf ethanol extracts from Angelica keiskei Koidzmi can be used as a natural antioxidant for development and utilization in the future.