不同生长期马齿苋茎叶提取物的体外抗氧化活性比较

Comparison of antioxidant activity in different growth periods of purslane extract from stems and leaves in vitro

研究不同生长期马齿苋茎叶提取物的抗氧化活性。分别用70%乙醇和水浸提不同生长期马齿苋茎、叶部分,用分光光度法测定其醇提物和水提物中多糖和总黄酮的含量,进行体外抗氧化活性实验。盛花期马齿苋茎中的多糖和黄酮含量最高,但水提物高于醇提物。不论是水提物还是醇提物,不同生长期马齿苋茎中的多糖含量高于叶,而叶中的黄酮含量高于茎。在实验浓度范围内,两种溶剂提取物均有良好的抗氧化活性,随着提取物浓度的增加对羟基自由基（·OH）的清除能力增强,而对Ce（Ⅳ）的还原能力并不都是随浓度的增加而增强。在添加量为0.10~0.60 m L时,水提物对·OH的清除能力强于Vc,各个生长期马齿苋茎、叶水提物的抗氧化力强于醇提物,同一生长期茎对·OH的清除率都大于叶。添加量为0.50 m L时,水提物对Ce（Ⅳ）还原率最大的是花蕾期茎和盛花期叶达到79.64%。添加量为0.80 m L时,水提物对·OH的清除率最大的是花蕾期茎高达82.81%,醇提物对·OH的清除率最大的也是花蕾期茎为75.86%。

The antioxidant activities of extracts from stems and leaves of Portulaca oleracea L. in different growth periods were compared. The ＇stems and leaves of Portulaca oleracea L, were extracted with 70% ethanol water solution and ultrapure water extraction in different growth periods, respectively. The contents of polysaccharides and flavonoids in purslane alcohol and water extracts were determined using spectrophotometry, and their antioxidant activities were tested in vitro. The results showed that flowering stems of purslane polysaccharide and flavonoids content was the highest. The water extract of purslane polysaccharide and flavone content was higher than that of ethanol extract. Whether water extracts and alcohol extracts of different growth period, purslane polysaccharide content in stems was higher than that of leaves, and the content of flavonoids in leaves was higher than stems. In the experimental concentration range, two kinds of solvent extracts have finer antioxidant activity. With the increase of the concentration of extracts, the hydroxyl radical （＇OH） scavenging ability was enhanced. The Ce （IV） reduction ability was increased with the increase of concentration not all. When the additive amount of purslane water extracts adding amount was 0.10-0.60 mL, the water extract of .OH scavenging ability was more than Vc. In each growth period antioxidant capacity of purslane water extract from the stems and leaves was more than the alcohol extract. In the same period, the scavenging ability of purslane extract from stems on hydroxyl radicals was greater than that from leaves. When the additive dosage was 0.50 mL, the reduction rate of water extract from bud stem and flowering leaf on Ce （IV） was the largest, reached to 79.64%. When the adding amount was 0.80 mL, the scavenging ability of water extracts from the buds and stems to .OH was the strongest, which could be achieved to 82.81%. When using ethanol as extracting agent, bud stem on scavenging rate of .OH was the largest, up to 75.86%.